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VIMOS User Manual

1. ID X IMAGE Y_IMAGE A IMAGE B IMAGE THETA IMAGE MAG MAGERR 1 233 036 549 141 66 651 4 305 8 9 9 7 4464 0 0001 2 891 844 360 569 53 105 7 911 87 4 7 9803 0 0002 3 100 238 84 054 60 828 24 763 10 0 11 2455 0 0053 4 601 006 67 561 428 910 9 910 0 6 9 9766 0 0027 5 1708 843 51 041 104 712 12 829 SO 99 0000 99 0000 6 978 752 48 620 12 126 4 303 12 4 12 7846 0 0047 7 1209 031 74 048 28 632 6 684 SA 53 10 1976 0 0008 8 1212 790 59 548 18 403 5 147 9 9 10 3681 0 0007 9 1127 769 61 476 21 994 6 201 CBI 8 5845 0 0002 10 1146 020 73 446 10 094 8 440 3 6 7 9 5569 0 0003 11 797 370 124 978 4 882 3 866 87 6 10 2443 0 0003 12 456 249 66 226 35 585 7 872 3 8 10 2253 0 0010 13 993 617 51 635 19 266 10 830 16 2 99 0000 99 0000 14 2036 250 59 659 58 085 8 955 0 7 10 4253 0 0012 15 281 472 76 981 10 187 7 927 ESSO 10 6445 0 0008 16 412 076 102 149 4 210 3 252 89 7 11 2830 0 0006 17 882 229 477 262 35 568 3 459 89 9 8 0405 0 0001 18 179 795 30 820 1 176 0 901 8 0 17 1447 0 0356 19 1205 669 89 548 4 645 2 893 6 0 11 3859 0 0007 20 1527 264 133 530 3 779 3 458 Do 10 6818 0 0003 21 871 428 246 348 9 820 4 277 89 1 9 4710 0 0002 22 1458 521 103 164 20132 20018 22 0 13 4509 0 0025 23 310 929 123 950 2 785 2 643 99 8 11 4401 0 0005 24 472 827 106 763 2 265 2 148 53 4 2 7780 0 0014 25 934 416 137 586 S201 26952 5252 0887 0 0004 26 385 186 121 721 2 487 2 315 SEO a 2
2. INS REF1 DIMX 30 INS REF1 DIMY 30 INS SLIT1 TYPE RECTANGLE INS SLIT1 ID 27467 INS SLIT1 OBJ RA 244 0057983398438 INS SLIT1 OBJ DEC 6 09309196472168 INS SLIT1 X 108 INS SLIT1 Y 2175 15 INS SLIT1 DIMX 58 INS SLIT1 DIMY 4 88 INS SLIT2 TYPE RECTANGLE INS SLIT2 ID 27313 INS SLIT2 OBJ RA 243 9036865234375 INS SLIT2 OBJ DEC 6 095680713653564 INS SLIT2 X 161 INS SLIT2 Y 394 478 INS SLIT2 DIMX 44 INS SLIT2 DIMY 4 88 INS SLIT3 TYPE RECTANGLE INS SLIT3 ID 26930 INS SLIT3 OBJ RA 243 9173889160156 INS SLIT3 OBJ DEC 6 101338863372803 INS SLIT3 X 263 INS SLIT3 Y 633 422 INS SLIT3 DIMX 38 INS SLIT3 DIMY 4 88 INS SLIT4 TYPE RECTANGLE INS SLIT4 ID 26695 INS SLIT4 OBJ RA 243 9308166503906 INS SLIT4 OBJ DEC 6 104647159576416 INS SLIT4 X 312 INS SLIT4 Y 867 445 INS SLIT4 DIMX 56 INS SLIT4 DIMY 4 88 INS SLIT5 TYPE RECTANGLE INS SLIT5 ID 26710 INS SLIT5 OBJ RA 243 9892578125 INS SLIT5 OBJ DEC 6 10461950302124 INS SLIT5 X 312 INS SLIT5 Y 1886 62 INS SLIT5 DIMX 56 INS SLIT5 DIMY 4 88 INS SLIT38 TYPE CURVE INS SLIT38 ID 1294 INS SLIT38 OBJ RA 54 63366317749023 INS SLIT38 0BJ DEC 35 58836364746094 INS SLIT38 X 1934 2 VIMOS User Manual VLT MAN ESO 14610 3509
3. INS SLIT38 Y 1748 86 INS SLIT38 DIMX 72 6812 INS SLIT38 DIMY 72 68 INS SLIT38 BEZIER DY 3 41463 INS SLIT38 BEZIER AX 0 INS SLIT38 BEZIER BX 0 INS SLIT38 BEZIER CX 72 6812 INS SLIT38 BEZIER XX 1897 86 INS SLIT38 BEZIER AY 0 INS SLIT38 BEZIER BY 0 INS SLIT38 BEZIER CY 37 0329 INS SLIT38 BEZIER YY 1734 33 INS SLIT46 TYPE RECTANGLE INS SLIT46 ID 26017 INS SLIT46 OBJ RA 243 9325103759766 INS SLIT46 0BJ DEC 6 108108043670654 INS SLIT46 X 381 9 INS SLIT46 Y 897 INS SLIT46 DIMX 18 78 INS SLIT46 DIMY 9 89 90 VIMOS User Manual VLT MAN ESO 14610 3509 6 5 User check list You can use this list to go step by step through the process and tick off each step one by one Step 0 most crucial Prepare you catalog s and image s You have prepared carefully your catalog s and have the corresponding VIMOS pre images ready You thought carefully of the objects in your catalog only objects you do not mind having a slit allocated to them are in there VIMOS pre image and contributed catalogs have common objects you did not modify your VIMOS pre image Step 1 Chose the right task to start with According to your input catalog you go to Step 2 1f you have a VIMOS pre image and contributed catalog to Step 3 if you have a VIMOS catalog Step 2 From VIMOS pre image and contributed catalog create a VIMOS catalog Skip this step if you have alr
4. 91 92 VIMOS User Manual VLT MAN ESO 14610 3509 Norm T Norm T 0 8 0 6 0 4 Norm T 0 2 Norm T Hit A EP A al ias prepa aa or pata Ly ds 1 1 1 360 380 400 TITO PTA 1 10 1 360 Wavelength nm 1 380 400 ny i 1 pa era rere 450 Wi nm La 550 Wi nm 600 600 550 Wl nm Figure Al U B V filter transmission curves VIMOS User Manual VLT MAN ESO 14610 3509 Norm T 0 8 E 0 6 S z 0 4 600 Wavelength nm poclisa iss tii hh Me ic le gen AP PEO PIES a Er e Pe E Fa 700 800 900 700 800 900 Wl nm Wi nm T T q T T T Va 1 1 1 1 1 1 800 300 1000 800 900 1000 Wavelength nm Figure A2 R Lz filter transmission curves 93 94 VIMOS User Manual VLT MAN ESO 14610 3509 0 8 0 6 3 Z 0 4 HH tt TO 20 4 A A A es ee 500 600 700 Wl nm ria PEE 400 0 8 E 0 6 2 04 lcd a Ta E A SA 400 500 600 700 Wi nm Z 04 fa ta EE ts E o et a Wl nm adri 600 700 800 900 100900 AA 600 700 800 900 1000 Wl nm Figure A3 OS blue OS red transmission curves VIMOS User Manual VLT MAN ESO 14610 3509 0 8 E E 0 6 5 20 4 0 pa pers
5. e Curved slits you picked the object and are now clicking madly in the Curved Slit window to determine the fancy curved slit but no little dots appear We have not found out why this happens every now and then but we know that even if you do not see them they are there spooky Try defining a few virtual points and click View Fit that should work e There are occasions in which the subroutine algorithm used to optimize the slit positioning SPOC does not converge In such cases you will see a core dump message If this happens for some of your masks please contact ESO s User Support at usd help eso org for a possible workaround 6 3 3 Other problems e There are reports of a possible bug the image is displayed but a pop up message appears stating ER ROR Fits file VIMOS image after which one can not proceed with the cross correlation If that happens the user can try to load the image again using the Open sub menu of the File menu in the skycat main window If that does not work please contact ESO s User Support at usd help eso org VIMOS User Manual VLT MAN ESO 14610 3509 6 4 Examples of catalogs 6 4 1 A contributed catalog The following shows an example of a contributed catalog Note that all mandatory columns 1D RA DEC are in as well as a couple of optional reserved columns X IMAGE Y IMAGE and a few user columns VL_color V_MAG All these will be carried over to the output of the Cross
6. 3 4 2 Rotator on sky Because of the atmospheric dispersion effects Sect 3 1 the orientation on sky for MOS and pre imaging observations is not a parameter set by the user but is forced by the system to be 90 All service and visitor mode users who have particular constraints for the orientation of their fields should request a waiver 3 4 3 VIMOS Mask Preparation Software VMMPS The use of VMMPS Chapter 6 is compulsory for the creation of the so called ADP Aperture Definition in Pixels files which are subsequently loaded into p2pp when preparing Observation Blocks ADP files will be used in Paranal to manufacture the masks ADP files should never be edited by hand Here are some general features of VMMPS for a quick reference guide Consult the VMMPS web page for instructions on how to retrieve the package and the documentation e VMMPS allows to define a mask in two situations From a contributed catalogue consisting of list of targets with accurate relative astrometry better than 0 3 rms Input catalog is a list of RA DEC coordinates This catalogue needs to have with the same relative astrometric accuracy coordinates of bright objects stars in the field of view These objects stars after detection on the pre images will be used to register the target coordinates to the VIMOS coordinate reference frame Some of these bright stars will be used as reference for acquisition From a catalog of target positions
7. CO Y Yu Y Y CO CO Y CO CO Dos ARAN AIJADONO NENENNERBEN TA TA TA TA TA TA TA A TA TA TA A Modify Flags NewRef Comp Forb Automatic Slit Assignment Here we have chosen to select according to the R magnitude say we changed our mind and decided to allow slits only for objects brighter than 22 5 despite the fact that our VIMOS catalog contains objects down to 66 VIMOS User Manual VLT MAN ESO 14610 3509 R 24 Notice the two new fields in the upper part of the window saying Min R MAG and Max R_MAG Enter there the values on which you want to select the catalog and hit return or click on Search below the data field The catalog display will be updated as well as the overlay on the image They will now show only objects fulfilling the new selection criteria And only these objects will be used for assigning slits in the next step VIMOS User Manual VLT MAN ESO 14610 3509 67 6 2 6 Step 5 First pass defining special objects Alright if you made it to here you are ready to assign some slits to some objects You are doing well so far In VMMPS you will first assign all special objects before the rest of the space will be filled automatically with objects We have 5 types of special objects e reference objects cyan diamonds e new reference objects cyan diamonds e compulsory objects blue triangles e forbidden objects yellow crosses e curved slits green squares They are all
8. 0 00022477421 PRO CCD MASK X_1_1 5 4715579e 07 PRO CCD MASK X_1_2 5 5136728e 10 PRO CCD MASK X_1_3 1 8931227e 13 PRO CCD MASK X_2_0 8 3582309e 08 PRO CCD MASK X_2_1 3 428154e 10 PRO CCD MASK X_2_2 4 1386207e 13 PRO CCD MASK X_2_3 1 420323e 16 PRO CCD MASK X_3_0 6 977006e 12 PRO CCD MASK X_3_1 5 0065001e 14 PRO CCD MASK X_3_2 8 499529799999999e 17 PRO CCD MASK X_3_3 2 9409612e 20 PRO CCD MASK YO 126 018852108 PRO CCD MASK YY 0 11921683 PRO CCD MASK YX 7 9496414e 05 PRO CCD MASK Y_0_0 0 20919197 PRO CCD MASK Y_0_1 0 00026838485 PRO CCD MASK Y_0_2 6 4661712e 08 PRO CCD MASK Y_0_3 1 2921672e 11 PRO CCD MASK Y_1_0 0 00039152516 PRO CCD MASK Y_1_1 1 644576e 07 PRO CCD MASK Y_1_2 7 9799032e 11 PRO CCD MASK Y_1_3 6 9466793e 14 PRO CCD MASK Y_2_0 2 9800619e 07 PRO CCD MASK Y_2_1 4 8490222e 11 PRO CCD MASK Y_2_2 1 4704649e 13 PRO CCD MASK Y_2_3 6 7603913e 17 PRO CCD MASK Y_3_0 8 9077175e 11 PRO CCD MASK Y_3_1 7 827672800000001e 15 PRO CCD MASK Y_3_2 3 7850445e 17 PRO CCD MASK Y_3_3 1 8410463e 20 INS REF1 TYPE SQUARE INS REF1 ID 22595 INS REF1 OBJ RA 243 9472351074219 INS REF1 OBJ DEC 6 144344329833984 INS REP Dex LOTT 37 INS REF1 Y 1153 78 87 VIMOS User Manual VLT MAN ESO 14610 3509
9. ES EUROPEAN SOUTHERN OBSERVATORY Organisation Europ ene pour des Recherches Astronomiques dans H misph re Austral O Europ ische Organisation fiir astronomische Forschung in der stidlichen Hemisph re ESO European Southern Observatory Karl Schwarzschild Str 2 D 85748 Garching bei Miinchen Very Large Telescope Paranal Science Operations VIMOS User Manual Doc No VLT MAN ESO 14610 3509 Issue 85 0 Date 01 09 2009 G Marconi S Bagnulo M Rejkuba F Selman Prepared A A hen Sew Approved dl O Hainaut Released da o Att Red q Date Signature il VIMOS User Manual VLT MAN ESO 14610 3509 This page was intentionally left blank VIMOS User Manual VLT MAN ESO 14610 3509 111 Change Record Issue Rev Date Section Parag af Reason Initiation Documents Remarks fected draft Oct 24 2002 all Draft delivered by VIRMOS Consortium 1 0 Feb 11 2003 all first release for P71 phase II and P72 Phase I 1 1 July 14 2003 all release for P72 phase II and P73 Phase I 1 2 Jan 12 2004 all release for P73 phase II and P74 Phase I 1 3 Jun 14 2004 all release for P74 phase II and P75 Phase I 5 0 Nov 26 2004 all release for P75 phase II and P76 Phase I 76 0 Mar 21 2005 2 7 3 5 7 3 6 6 release for P76 Phase I 3 7 7 76 1 June 30 2005 2 1 2 2 2 3 2 6 3 4 3 533 6 3 7 4 6 release for P76 Phase IT 77 0 Aug 31 2005 3 6 1 3 7 2 release for P77 Phase
10. TS 08 39 09 19 58 93 41 54 79 32 32 99 24 84 VIMOS User Manual VLT MAN ESO 14610 3509 6 4 2 A VIMOS pre image catalog The VIMOS pre image catalog was obtained by running our favorite source detection algorithm on the original VIMOS pre image processed by the ESO pipeline The output was just plain x y detector coordinates we added manually a unique ID That list together with the transformation matrix in the header of the pre image will be transformed into ra dec and cross correlated with the contributed catalog This will in turn allow to determine the best transformation from ra dec of the contributed catalog to x y in pixel coordinates ID X_IMAGE Y_IMAGE 1 76 554 497 854 2 78 566 258 963 3 100 714 83 548 4 445 282 69 524 3 1589 924 51 424 6 767 057 126 705 7 1391 149 121 832 8 229 290 ESP RO 9 800 180 151 801 10 1010 375 156 611 11 1351 326 177 466 12 980 319 184 649 13 548 496 LIZ LOY 14 1534 235 204 140 15 1310 024 208 284 16 823 662 233 845 17 209 727 220 367 18 706 188 228 008 19 1797 688 243 397 20 1936 794 250 302 21 1996 330 245 786 22 1046 128 251 701 23 1737 622 249 215 24 2018 013 246 191 25 1851 735 266 140 VIMOS User Manual VLT MAN ESO 14610 3509 85 6 4 3 A VIMOS catalog The following shows an example of a VIMOS catalog
11. VIMOS User Manual VLT MAN ESO 14610 3509 35 IFU on the sky is with the North up and the East to the right The increasing positive position angle on the sky east of north corresponds to the positive rotator angle Therefore the value of this keyword should be equal to the desired position angle PA on the sky see Fig 2 5 Optional additional offsets in alpha and delta Alpha Offset and Delta offset with respect to the coordinates of the object The coordinates at the center of the IFU are the coordinates specified in the Target Package plus the offsets here specified This can be useful e g to define small offsets between the initial pointings on the same field over several OBs e Get Guide Star From Two options are offered for this parameter CATALOGUE This is the default option for which the guide star will be searched through a catalog and will be selected at the telescope by the Telescope Operator If this option is selected the subsequent fields Guide Star RA DEC will be ignored Given that the quasi total Nasmyth field of view is accessible to choose a guide star in IFU mode the users can safely use this option SETUPFILE If this option is selected the guide star that will be used is the one for which the coordinates are defined in the Guide Star RA DEC fields As indicated above it is unlikely that this option is required in IFU mode Note that Guidecam tool is not intended to be used to select guid
12. common to all quadrants 1 slit A pixel multiplex LR blue OS Blue 400 670 nm 220 5 3 4 LR red OS Red 590 915 nm 260 7 3 4 MR GG475 490 1015 nm 720 2 5 1 HR blue None 415 620 nm 2550 0 51 1 HR orange GG435 525 740 nm 2650 0 6 1 HR red GG475 645 870 nm 3100 0 6 1 Note new HR red VPHG grisms have been installed fon October 5 2005 pseudo slits With the high resolution grisms the spectral coverage is determined also by the fixed positions of the pseudo slits in the focal plane but it varies slightly from quadrant to quadrant The spectral coverage for each quadrant derived from the automatic reduction of standard star observations with VIMOS pipeline is listed in the Table 2 8 2 4 4 Spectral resolution In IFU mode spectral resolution is fixed by the combination grism fiber size the fiber FWHM is about 3 2 pixels corresponding to 0 67 The spectral resolution is about 1 25 times the spectral resolution obtained in MOS mode with a 1 slit width The spectral resolution for various grism filter combinations is given in Table 2 7 2 4 5 Multiplex characteristics The same multiplex capability described in MOS mode is also used in IFU mode With the low resolution grisms there are 4 pseudo slits of fibers along the dispersion direction With intermediate and high resolution grisms only the central pseudo slit is used in practice by masking the entrance field of the IFU so that the other pseudo slit
13. coordinate in pixels on the VIMOS pre image e Y_IMAGE the y coordinate in pixels on the VIMOS pre image The optional columns whose names are reserved are FLAG shall be one off C compulsory R reference F forbidden S select able no blank entry is supported any other flag will be replaced by S select able e X WORLD e Y WORLD the coordinates of the object in the world coordinate system not used by VMMPS A IMAGE the semi major axis in pixels e B IMAGE the semi minor axis in pixels THETA IMAGE the position angle in degrees positive x axis is O positive counter clockwise of the object e X RADIUS the object size in the x spatial direction of the detector A IMAGE B IMAGE and THETA IMAGE are used to compute X RADIUS The column X RADIUS is used when one or more of A IMAGE B IMAGE THETA IMAGE are not given otherwise it is overwritten If X RADIUS and any one of A IMAGE B IMAGE THETA IMAGE is missing the object size in x is set to 10 pixels If X RADIUS gt 45 pixels the object is automatically flagged as forbidden by the software 2 Any other columns can be added with any names The catalog later allows to constrain with any number of criteria on any number of columns the select able objects So typically you might want to add color magni tude or may other columns that you might want to use as selection criteria to the catalog An example is given in Section 6 4 The reason for this is that the
14. from the pointing position along the slit then the second exposure is taken 2 up along the slit with respect to the previous exposure and the third exposure is taken at the same position as the second VIMOS User Manual VLT MAN ESO 14610 3509 39 4 6 3 VIMOS ifu_obs_Offset This template is to be used for observation with the Integral Field Unit The parameters of this template are e Exposure time in seconds This is the integration time in seconds per exposure e Filter The available filters are U B V R I z OS blue OS red GG435 GG475 and no filter Only standard filter grism combinations are allowed as indicated in Table 2 3 Other combina tions should be requested with a waiver e Grism The available grisms are LR_blue LR_red MR HR_blue HR_orange HR_red In order to produce a valid OB the filter and the grism in the first observation template following the acquisition template should be the same as the one selected in the acquisition template e IFU Magnification This parameter defines the sampling and correspondingly the field of view of the IFU The 2 available samplings are 0 67 arcsec fiber and 0 33 arcsec fiber To produce a valid OB the magnification should be the same in every template of the OB e IFU Shutter This parameter is only meaningful when using the LR grisms In LR spectroscopy there are 4 rows of fibers along the dispersion direction whereas in MR and HR modes only one slit
15. green with the arrow pointing to the N a circle of 11 arcminutes radius green corresponding to the unvignetted telescope focal plane Beyond this radius there is vignetting by the tertiary mirror of the telescope a circle of 13 5 arcminute radius red corresponding to the maximum search radius for guide stars 45 46 VIMOS User Manual VLT MAN ESO 14610 3509 XA guidecanLile Release 1 25 1 2 Le File View Graphics Object dss179 4 X 453 0 Y 1215 0 Value 3525 12 30 31 319 5 30 09 24 39 Equinox J2000 Min 2000 Max 19231 Bitpix 16 Low fria High asos Auto Set Cut Levels Es zz Si zit E let Figure 5 1 Guidecam main panel skycat Superimposed to the DSS image of the field is in yellow the projected shadow of the Telescope Guide Probe in green the VIMOS field of view rectangle and in green and red the 11 and 13 5 arcminute radii corresponding respectively to the unvignetted Nasmyth field of view and to the maximum search radius for guide stars e in blue the rotation axis of the Guide Probe arm e the position of the USNO stars selected in the USNO at ESO panel figure 5 3 The stars are indicated with white circles 5 3 The USNO at ESO panel The USNO at ESO panel figure 5 3 provides for the following entries e Search radii min and max The default value for the maximum radius is 12 arcminutes with a max imum permitt
16. in pixel coordinates extracted from a VIMOS image e VMMPS maximizes the number of slits that can be assigned to the targets in the input catalogue in one or more masks depending on user s choice Upon realization of a first mask definition VMMPS allows manual interaction to unselect targets define curved slits tilted slits etc However note that manual modification of the mask definition should be done only by experienced users and with care e VMMPS allows to define some objects as compulsory e VMMPS requires that some bright stars are defined as reference targets for acquisition purposes Figure 3 2 shows the VMMPS Graphical User Interface 24 VIMOS User Manual VLT MAN ESO 14610 3509 INGC2243 259 0 2428 0 E 7 107 59 57 125 1 10 40 07 01 inox 2000 259 65535 ix 16 5000 High rsooo Auto Set Cut Levels d Grid E Figure 3 2 VMMPS Graphical User Interface Example of ADP file superimposed to field of view VIMOS User Manual VLT MAN ESO 14610 3509 25 3 4 4 Finding charts Finding charts for service mode OBs need to be prepared with VMMPS and show all targets with slits over plotted 3 4 5 Visitors using MOS Visitors using the MOS mode are requested to prepare Observation Blocks ahead of their scheduled visitor run and upon completion of their pre imaging observations like in service mode This is to guarantee that visitors will have a suff
17. of fibers is used hence the variation of field of view between LR and MR and HR modes In case the object of interest is of limited size in LR mode and if only the central 1 4 x 1 4 of the field of view is needed it is possible with the IFU Shutter option to mask the outer part of the IFU always masked in MR and HR modes This allows to avoid second order overlap due to sky and or background objects between the 4 adjacent slits along the dispersion direction True means that the shutter is in place and masks the external part of the IFU False the default value means that the mask is not in place and the full IFU field of view is available To produce a valid OB the mask shutter option should be the same in every template of the OB This parameter is ignored when MR or HR grisms are used e Return to Origin T F This parameter defines whether or not after a dithered set of ob servations the telescope will return to the reference position This parameter is in general to be left in the default value T in service mode If another value is desired in service mode a waiver should be requested e Number of Telescope Offsets This parameter defines the number of telescope offsets dur ing the template The number of exposures taken at each telescope position is determined by the next parameter Number of exposures per telescope offset The pattern of offset is defined in the List of offsets arcsec CORRECT LABEL and List of offsets arc
18. offset and read out noise are constant along the entire CCD In spectroscopic mode the full CCDs 2048 x 4096 pixels are read out in imaging mode readout is win dowed to 2048x2400 pixels In fact in both spectroscopic mode and in imaging mode the CCDs are vignetted by some hardware In spectroscopic mode the illuminated area is about 1970x4096 pixels and in imaging mode the illuminated area is about 1970x2300 pixels The actual values depend on the individual CCDs The default readout modes are indicated in Table 2 10 VIMOS User Manual VLT MAN ESO 14610 3509 17 Table 2 10 Detector Readout Modes and Characteristics VIMOS Mode Size Speed Binning Gain Port Windowing Readout time Imaging 4x2kx2k 225kpxs 1x1 Low 1 port Not supported 1m Spectroscopy 4x2kx4k 225kpxs 1x1 High 1 port Not supported 1m 2 5 2 Controllers The 4 CCDs are controlled by two FIERA controllers The detectors of channel 2 and 3 are controlled by FIERA A VIMOSA the detectors of channel 1 and 4 by FIERA B VIMOSB 2 5 3 Read out noise and conversion factor Table 2 11 indicates the readout noise and gain values for the 4 chips Note that these values are subject to change and are indicated here only for reference Exact values have to be found in the image headers Table 2 11 Detector read out noise and conversion factors For reference only subject to change Chip Re
19. 0 and bottom right panels refer to the situation with rotator at 90 The corresponding positions of the detectors on sky are shown in the left panels The gap between the quadrants is approximately 2 The pointing coordinates correspond approximately to the center of the gap 2 2 2 Image Quality For the most updated information please have a look at the Quality Control and Data Flow Operations Web pages The focal plane of VIMOS is not strictly flat because of the complexity of the optical elements involved This results in slight focus variations across the field which translates in a variable PSF from the center to the periphery The sky concentration effects are in any case small and negligible for flat field and photometric calibrations 2 2 3 Imaging Filters VIMOS provides positions for 10 broadband filters in any of the four channels Presently installed filters inside the instruments are U Bessel BVRI Gunn z and some order separation filters Only the U BVRIz filters are available for imaging programmes The special U is not a standard Bessel filter see Figure A1 With the Bessel J and Gunn z filters the CCDs show fringes of approximately 7 The complete list of filters together with the transmission curves are presented in Appendix 7 see Table A1 and Figs Al to A4 ESO will not accept requests for user s supplied filters for VIMOS 2 3 Multi Object Spectroscopy MOS A variety of grisms with differ
20. 2 Fiber arrangement and spatial characteristics o oo 13 Do Special TARO salas a ac am sai A Sa a a 13 244 Spectral resolution sss s srame ee ae A ee ee a ee 15 249 Mualhplex Chatacienshos 14 004 ebb a ee a Ss da e vd gua wed 15 Zo DISCOS ooo viga Raa Oe da ORS we bere dd Sak a bare Baa Ba Se eA ee ES 15 25 Detector read outmodes o oe e sace bbb each bee ed ee ee eed 16 25 2 COMO is arte oe ase eR wn de Hh ly o aay ae ee we A 6 DD 17 vi VIMOS User Manual VLT MAN ESO 14610 3509 25 3 Read out noise and conversion factor ss coco src ae See a 17 2298 FONDIDE o ciora eo ka eb ee ER ee bp ee ee ae ee SS 17 ey SUBES a kB Sle ah Ee AA a ae a 17 25 6 More TOMAN iss bbe ee a Pe ed a Se ee i 17 20 Calbration UMES es pes ag a ae ee een ee ee GR ee ad 18 20 FERES cs baka Paka Re OORT do direto do Yo pe SO toe be eh et O eae ea ee 18 3 Observing with VIMOS 19 30 1 Interactions with the telescope i coe aoc coue Se ee eee a 19 3 0 2 Guide stars and Guidecam software tool 2 2 oo o ee 19 2303 COMUN OHSAS acs ae oe Pa ea Baha Hee eed ae ai RG E oe Ho 20 3 0 4 Telescope and Instrument Focus o o e eee eee 20 3 1 Atmosphere Dispersion cocos dae e ee BR a da oes 20 A oa ao AA 20 Imagine IMG ida e ae aw di ij E a 21 Jad AIN 21 3312 CINCO IMARIOS a acom a daa a a A 22 3 3 3 IMG mode calibration plan 26 46 pras Yaka Bary a OU Ga Bede Bo 22 3 3 4 IMG mode pipeline 2 2 2
21. 2D input micro lens is coupled to an optical fiber The output of the fibers is re arranged on a linear set of micro lenses to produce an entrance slit to the spectrograph at the mask focal plane location Each IFU mask one for each channel of VIMOS has a set of 4 fibre slits or pseudo slits for a total of 6400 fibers 12 Table 2 4 MOS spectral resolution and spectral ranges observed using the mask for spectrophotometric standard stars VIMOS User Manual VLT MAN ESO 14610 3509 Grism Default Order Spectral Number Spectral Res Dispersion Spectral sorting filter range of pixels 1 slit A pixel multiplex LR blue OS Blue 370 670 nm 550 180 5 3 4 LR red OS Red 550 950 nm 550 210 7 3 4 MR GG475 480 1000 nm 2000 580 2 5 2 MR OS red 550 970 nm 2000 580 2 5 2 HR blue Free 415 620 nm 4096 2050 0 51 1 HR orange GG435 520 760 nm 4096 2150 0 6 1 HR red GG475 630 870 nm 4096 2500 0 6 1 1 With HR blue grism the spectral range in quadrant 1 for a standard star is 400 620 nm 2 With HR orange grism the spectral range in quadrant 1 for a standard star is 505 745 nm 3 With HR red grisms the spectral range in quadrant 1 for a standard star is 650 865 nm 4 New HR_red VPHG grisms have been installed from October 5 2005 Table 2 5 Spectral coverage AA for three positions of the slit in field of view MOS mode Grism Order sorting AA AA AA filter CCD center CCD botto
22. 3 5 6 IFU mode pipeline See http www eso org qc pipeline status html for the information concerning the latest status of the ESO pipeline 3 5 7 IFU mode Exposure Time Calculator The approximate limiting magnitudes in IFU mode can be obtained from the exposure time calculator available on the ESO WEB pages http www eso org observing etc 3 6 VIMOS overheads The current overall efficiency of VIMOS is around 65 70 depending which mode is used The way in which some functions are operated may change at any time Consequently we cannot give here an estimate of the overheads that is reliable on the long term The user is referred to the current Call for Proposals and to the VIMOS web pages for the most updated estimate of the overheads http www eso org sci facilities paranal instruments vimos overview html 28 VIMOS User Manual VLT MAN ESO 14610 3509 Chapter 4 VIMOS templates 4 1 Introduction This section describes the VIMOS templates Templates are to be used during phase II for service and visitor programmes Templates are characterized by signatures to be filled in by the users with P2PP Templates are grouped to gether to build an Observation Block OB which typically consists of one acquisition template and one or more observing or calibration templates At the telescope OBs are passed to the instrument and executed according to the user defined parameter values Unless specified otherwise the informa
23. 37 01136 25300 36 53 01405 00700 34 40 01569 Modify Flags Ref NewRef Comp Forb Curved UnSel Automatic Slit Assignment lad gt There are reports of a possible bug loading the image in some circumstances See Section 6 3 64 VIMOS User Manual VLT MAN ESO 14610 3509 Let s focus on the catalog window We dragged it a little wider to see all columns That window displaying your catalog might look like this a File Edit Options Search Options Object Name E Equinox 2000 NE 35 37 06 855 SS T Max Radius 5 450 10000 Select Area Set From Image Search Results 134 RADTU loo pa IMA 33000 01062 82000 E 01240 13000 e 01452 20000 i 01488 00110 00111 00391 00007 01679 01361 01284 DENZIJRAON OO RE O A A o y H Hl vana vv nan NN S Sia 3 3 J 3 3 3 Se 3 Si Pot Modify Flags NewRef Comp Forb Automatic Slit Assignment Your catalog has internally been transformed into skycat format and is now displayed with the standard skycat catalog window This window shows all objects in given radius 5 45 arcmin by default from the center of your pre image The data section in the middle of the window allows you to look at your catalog check values for given objects etc A click on an object in the image display will highlight that object
24. 4M ade Figure 4 2 P2PP Example of a MOS OB 4 5 2 VIMOS mos acq Mask This template is used for the acquisition of a field to be observed in MOS mode Note that the acquisition image covers only the central 2048 x 2400 pixels of each of the 4 CCDs whereas the spectroscopic images use the full CCD size 2048 x 4096 pixels Preparing a MOS acquisition template requires that masks have been prepared with VMMPS The output of VMMPS are Aperture Definition Files in Pixels ADP files Information concerning the target coordinates and equinox are taken from the ADP files and are automatically loaded in the P2PP target package when including the first ADP file in the template Figure 4 2 shows the P2PP window with an example of a MOS Acquisition The parameters specific to this template are e Exposure time in seconds This is the integration time for the acquisition image that will be taken through the mask to check the position of the reference stars and of the science target A typical value is 60s depending on the brightness of the reference stars defined with VMMPS Filter This filter is the one to be used for the acquisition image It is mandatory to choose the same filter as the one used for the pre imaging Waiver is requested in order to allow the selection of a different filter but see Sect 3 3 1 of this manual The available filters are U B V R I z OS blue OS red GG435 GG475 and no filter Optional addi
25. As mentioned under Grism the value set are giving you the maximum spectral length 500 pixels in LR mode 2000 pix in MR mode 4000 pix in HR mode centered around the zero deviation wavelength of the grism The software will guarantee that length for all spectra On the other hand this will constrain the physical region on the mask in which it can place slits E g if you pick the full range in HR mode only sources in a narrow band in the middle of the detector will be picked It is thus a good idea to reduce the range to the strict minimum you need This will allow to select more objects e The Number of Masks you can produce one or more masks for a given field If more than one mask is selected the reference objects will be placed in al masks the other special objects allocated in order of priority The task will fill the first masks with slits then the second with objects that have not been allocated yet and so forth e The Main Name of your ADP this name will be extended by the quadrant number the mask number and the grism name when your ADP files get written on disk Once you have set up all the above parameters you can Assign Slits at the bottom of the window This will produce a log shown in the middle sub panel telling you how many select able stars were found in the catalog the number of special objects the total of different placed slits If you are satisfied with the results click Close and Save and m
26. Grism The available grisms are LR blue LR red MR HR blue HR orange HR red IFU Magnification This parameter defines the sampling and correspondingly the field of view of the IFU The 2 available samplings are 0 67 arcsec fiber and 0 33 arcsec fiber To produce a valid OB the magnification should be the same in every template of the OB IFU Shutter This parameter is only meaningful when using the LR grisms In LR spectroscopy there are 4 rows of fibers along the dispersion direction whereas in MR and HR modes only one slit of fibers is used hence the variation of field of view between LR and MR and HR modes In case the object of interest is of limited size in LR mode and if only the central 1 4 x 1 4 of the field of view is needed it is possible with the IFU Shutter option to mask the outer part of the IFU always masked in MR and HR modes This allows to avoid second order overlap due to sky and or background objects between the 4 adjacent slits along the dispersion direction True means that the shutter is in place and masks the external part of the IFU False the default value means that the mask is not in place and the full IFU field of view is available To produce a valid OB the mask shutter option should be the same in every template of the OB This parameter is ignored when MR or HR grisms are used 44 VIMOS User Manual VLT MAN ESO 14610 3509 Chapter 5 Guidecam Tutorial This chapter contains the in
27. Guide stats POLEN lt esos a Be o ede a A Be SE A Sk a ae a 48 6 VMMBPS Tutorial 51 6 1 The VMMPS philosophy s ca 2 65 G6 be rena nad ee a 51 6 1 1 What does VMMPS dO o e s cee ce eee Bow eee Se wa ee ewe 51 6 1 2 This is not FIMS you have little chance for interaction 51 6 1 3 The importance of your catalos cuca PR ee Se eee ee we 51 6 1 4 The different catalogs that you can come with oo o 52 6 2 SlepeDV slep guide coco hae as eRe Pe ea a a aaa a 53 6 2 1 Step O most crucial Getting ready preparing your catalogs 53 6 2 2 Step 1 What is your starting point ee ee 58 6 2 3 Step 2 Transforming your contributed catalog into a VIMOS catalog 60 6 2 4 Step 3 Starting VMMPS for mask definition o o 63 6 2 5 Step 4 optional Re arranging your VIMOS catalog 65 6 2 6 Step 5 First pass defining special objects o ooo oo 67 6 2 7 Step 6 The automatic slit assignment your first ADP draft 73 6 2 8 Step 7 optional Fine tuning last corrections o ooo o 76 6 2 9 Step 8 Writing your final ADP you have succeeded 79 VLT MAN ESO 14610 3509 viii VIMOS User Manual 6 2 10 Loading verifying previously defined mask 6 3 Troubleshooting and known problems 6 3 1 Cross correlationtask 6 3 2 Automatic slit assig
28. HR blue HR orange HR red Number of exposures per telescope offset This parameter defines how many ex posures are taken for each offset position 1 or 4 quadrants This determines whether the standard star will be positioned in one or four of the quadrants of the instrument As many exposures as defined in Number of exposures per telescope offset will be taken at each telescope position 1 or 4 Slit Width Define which of the slits available in the masks will be used The width of the available slits are 0 8 1 0 1 2 1 5 1 8 2 0 2 5 5 0 Once the user select the slit width the rest is totally automatic the star will be offset from the acquisition box to the selected slit in the first quadrant and then moved to the same slit in the other quadrants 42 VIMOS User Manual VLT MAN ESO 14610 3509 4 7 5 VIMOS ifu cal Specphot This template is used for the observation of a spectrophotometric standard star in IFU mode It is to be used in a OB with the VIMOS ifu acg Preset acquisition template The parameters of the template are e Exposure time seconds This is the integration time in seconds per exposure Filter The available filters are U B V R I z OS blue OS red GG435 GG475 Grism The available grisms are LR_blue LR_red MR HR_blue HR_orange HR_red In order to produce a valid OB the filter and the grism in the first observation template following the acquisition template should be the same
29. I 77 2 Dec 01 2005 Appendix release for P77 Phase II 78 0 Mar 01 2006 none release for P78 Phase I 78 1 Jun 06 2006 all release for P78 Phase IT 79 0 Aug 23 2006 front page and release for P79 Phase I fonts 79 1 Dec 13 2006 Added clarifica tions about instrument FoV release for P79 Phase IT Phase II 80 0 Feb 28 2007 Calibration plan on release for P80 Phase I and II sky 81 0 Aug 31 2007 release for P81 Phase I and II 82 0 Mar 05 2008 release for P82 Phase I 82 1 Mar 05 2008 release for P82 Phase I and II 83 0 Aug 31 2008 Pre imaging validity comment and release for P83 Phase I 84 0 Feb 28 2009 Fixed broken links for new ESO pages Merged VMMPS and Guidecam manuals 84 1 March 11 2009 4 5 1 4 6 1 4 6 2 Clarified offsets description Modified reference ob 4 6 3 ject position recommendation 84 2 March 26 2009 4 5 1 4 6 1 Fixed wrong description of offsets and created new Figs 4 4 and 4 5 84 3 March 26 2009 4 5 1 4 6 1 Minor fixes 84 4 July 1 2009 3 4 3 4 6 x Further offsets description and other minor fixes for Phase II 85 0 Sep 1 2009 1 5 3 4 3 4 7 7 Added VIMOS IFU TwFlat template description Normal update for P85 Phase I 1v VIMOS User Manual VLT MAN ESO 14610 3509 This page was intentionally left blank Contents 1 Introduction 1 Li BOONE sara palma ta aaa ia bees tae beh bed wee 1 1 2 More Information on VIMOS oo 544 6544 22 24 ea 24 baa Sedaka ee ada e
30. Manual VLT MAN ESO 14610 3509 Chapter 9 Template Signature Files for Observation and Acquisition A1 Acquisition Templates The following tables list the parameters of the VIMOS acquisition templates VIMOS img_acq_Preset Keyword Range Label in p2pp INS FILT NAME UBVRIz Filter TEL ROT OFFANGLE 180 180 Rotator on sky TEL TARG OFFSETALPHA 3600000 3600000 Alpha Offset TEL TARG OFFSETDELTA 3600000 3600000 Delta Offset TEL AG GUIDESTAR SETUPFILE CATALOGUE Get Guide Star From TEL GS1 ALPHA 0 240000 Guide Star RA TEL GS1 DELTA 900000 900000 Guide Star Dec TEL GS1 PPOS POS NEG Guide Probe Position TEL TARG ALPHA RA of the Field Center TEL TARG DELTA DEC of the Field Center TEL TARG EQUINOX 2000 3000 Equinox TEL TARG EPOCH 2000 3000 Epoch TEL TARG PMA 10 10 proper Motion Alpha TEL TARG PMD 10 10 proper Motion Delta TEL TARG ADDVELALPHA 15 15 Additional Velocity RA TEL TARG ADDVELDELTA 15 15 Additional Velocity DEC A2 Observation Templates A3 Template Signature Files for Calibrations 103 104 VIMOS User Manual VLT MAN ESO 14610 3509 VIMOS_mos_acq Mask Keyword Range Label in p2pp DET WIN1 UIT1 1 1000000 Exposure time seconds INS FILT NAME UBVRIz Filter TEL AG GUIDESTAR SETUPFILE CATALOGUE Get Guide Star From TEL GS1 ALPHA 0 240000 Guide Star RA TEL GS1 DELTA 900000 9
31. are oriented S and the y axes are oriented E bottom panels Note that position angle increases as rotator angle 8 VIMOS User Manual VLT MAN ESO 14610 3509 Table 2 2 VIMOS Imaging characteristics and performance Field of view 4x7 x 8 separated by 2 gaps illuminated CCD area 2048 x 2350 pix slightly vignetted on the corners outside 8 Pixel scale 0 205 pixel Image Quality 80 encircled energy in 0 4 within the whole field Filters U Bessel BVRI Gumn z see section 7 F ratio 1 88 Limiting Magnitudes in 1h V 27 7 1226 6 50 detection for a point source V 26 5 1225 4 50 detection in 3 for a galaxy Orientation ON SKY VIMOS FoV IMAGING MOS MODE Rotator angle PA 0 IFU Figure 2 3 Orientation of the VIMOS field of view on sky for position angles 0 and 90 in IMG and MOS mode VIMOS User Manual VLT MAN ESO 14610 3509 9 VIMOS FoV ORIENTATION ON SKY ON DETECTOR Rotator angle PA 0 Rotator angle PA 90 E N Q2 Ql Q2 Q3 y gt a N l l Figure 2 4 A comparison of the orientation of the VIMOS field of view as seen on sky left panels and on detector right panels for position angles 0 and 90 in IMG and MOS mode 10 VIMOS User Manual VLT MAN ESO 14610 3509 Figure 2 4 shows the instrument FoV keeping fixed the detectors with x axes increasing to the right and y axes increasing to the top Top right panels refer to the situation with the rotator at
32. as the one selected in the acquisition template IFU Magnification This parameter defines the sampling and correspondingly the field of view of the IFU The 2 available samplings are 0 67 arcsec fiber and 0 33 arcsec fiber To produce a valid OB the magnification should be the same in every template of the OB IFU Shutter This parameter is only meaningful when using the LR grisms In LR spectroscopy there are 4 rows of fibers along the dispersion direction whereas in MR and HR modes only one slit of fibers is used hence the variation of field of view between LR and MR and HR modes In case the object of interest is of limited size in LR mode and if only the central 1 4 x 1 4 of the field of view is needed it is possible with the IFU Shutter option to mask the outer part of the IFU always masked in MR and HR modes This allows to avoid second order overlap due to sky and or background objects between the 4 adjacent slits along the dispersion direction True means that the shutter is in place and masks the external part of the IFU False the default value means that the mask is not in place and the full IFU field of view is available To produce a valid OB the mask shutter option should be the same in every template of the OB This parameter is ignored when MR or HR grisms are used Number of exposures per telescope offset This parameter defines how many ex posures are taken for each offset position 1 or 4 quadrants Th
33. being the top priority These objects will be allocated slits immediately after reference objects have been defined on the mask i e VMMPS will make sure that they get slits allocated if not blocked by a reference object If two compulsory object block each other VMMPS will allocate one in this mask and the other in the next mask of the series if applicable To flag an object as compulsory select the button Comp after having clicked on the object in the image display The FLAG of the object will be set to C Compulsory in the catalog If you added a column FLAG in your input catalog this flag can be used to set high priorities Forbidden objects You can exclude individual objects from the automatic slit assignment task To do so select the button Forb after having clicked on the object in the image display If the FLAG of an object is set of F Forbidden that object will not be considered for slit assignment This has the same effect as removing the object from the catalog The cases in which you might need this are rare it application useful when you use the same catalog for different purposes E g imagine that you use a single catalog to prepare masks for two different grisms and that you have a few objects for which blue spectra are useless These objects could be flagged manually forbidden when preparing the masks for the blue grisms and save you the time to duplicate the catalog VIMOS User
34. correlation task i e stored in the resulting VIMOS catalog that will serve as input to VMMPS ID o JOS 0140 NRP O0O0O Joc WN FP WNHNNNNNNNNN NF FF FR PR RPP CO O JOS ABR WNHNEFR CO O Y Y Y y Y Y COCO WWW y Y y Y y Y Y Y Y LY ww WwW RA 1 46 1 49 130 135 6551 54 01 53 1 56 LB 27 NNN NNN NH N 222 222 222 222s 222 222 222 222 222 zzz SACA 1 58 TS Bu 02 03 03 03 03 04 05 06 08 08 08 0 65 05 02 31 69 98 33 18 29 03 23 47 22 Ll 2 22 11 92 i222 1 22 84 P22 1 221 AA 2281 2221 22 sl ODA OB WN y 28 39 AB 66 96 99 20 s93 DEC 3 1413443 3 Pala 37 15 04 3 7 40029 37116 22 3 7132263 1 37 11 34 37 13 54 37 05 41 370852 Lo 37 08 08 TELAS 38 1807201 I TA LOS 3 8 3 10002135 37 20 40 37 05437 3 206739 37213406 37 14 42 372 162 31 37227240 SB MAME 252 4 BELO S35 L3G HITA 3 71513 32 373100939 37 15 47 El ia OP DANOANAT OWA OH Ja Paso J Jooo0pPs OoqGqQgqw0an0a JN VI _color 1 751 948 174 2099 927 063 198 3 12 399 924 8833 V MAG 2 3 4 ASA DiS 23 23 2 3 234 83 23 22 2 3 23 23 5 23 22 23 23 85 22 Ls 23 LI 23 22 230 23 Koo 23 22 234 22 22 22 26 39 33 17 Sih 26 44
35. ee ee ea eS 23 3 3 5 IMG mode Exposure Time Calculator o e a 23 3 4 Multi Object Spectroscopy MOS o 23 A ii AA A ek a ee go ew ad 23 Sie ROMOrOnSky A 23 3 4 3 VIMOS Mask Preparation Software VMMPS o o o o o e 23 344 Fmding chants A ee bee he ee eee Ee oa Ba es 25 34 5 Visitors using MOS 2 cee eh dba eee a ee a a 25 34 6 MOS mode grismrrilter settip so cs se mea a ee ee 25 3 4 7 MOS mode attached night time calibrations o a 25 3 4 56 MOS mode calibration pla soe e 4 40 a ee ern e ee Re a 25 Sa MOS Mode pipelines 2 wk Cae a Poe oe Ba toe he eee ede a eee de He 25 3 4 10 MOS mode Exposure Time Calculator o o ee eee 26 3 3 Integral Field Unit EU sam sima di a A A A 26 25l ACQUISINOMACCUMEY lt a eee Ra a a EE DADE a S ee ee a 26 de Ditherneiiier patteri ose socii a A a a A SO ae 26 30 3 IFU mode grsm E filter setups o s e menos es oe li oa AE 26 3 5 4 IFU mode attached night time calibrations o a 26 35 5 TEU mode calibration plat 6 ead e ba cd va bd da a Yo 27 33 6 TFU mode pipelh sc xo ee eee eee ee eee E 27 3 5 7 IFU mode Exposure Time Calculator o o e 27 36 VIMOS overheads ceci a a E do a ee o 27 4 VIMOS templates 29 4 A 29 4 2 Template Memes s o scra ak a a ee td A DS a 29 VIMOS User Manual VLT MAN ESO 14610 3509 Vil ao Things to know gt Remind
36. has been identified you can take note of its position by pressing the Get Guide Star Coords of the Guide Probe Settings panel This popups an information panel con taining the RA and DEC of the selected guide star and indicating whether the position of the guide probe is positive or negative alternate position These coordinates as well as the guide probe position should be noted and further entered manually into P2PP in the corresponding fields Guide Star RA Guide Star DEC and Guide Probe Position of the VIMOS_img_acq_Preset template 48 VIMOS User Manual VLT MAN ESO 14610 3509 K USNO at ESO File Edit Options Catalogs Archives ImageServers DO Figure 5 3 GuideCam the USNO at ESO panel Finally the Get Guide Star From should be set to SETUPFILE see VIMOS Template Refer ence Guide 5 5 Generating Finding Charts Guidecam should be used to generate finding charts for VIMOS imaging and pre imaging modes Under the File menu selectthe Make finding charts option A new pop window will appears to be filled with Run ID P I name and OB name s Click on Draw to obtain a preview of a finding chart compliant with the rules defined for phase 2 proposal preparation Then press Save to produce a postscript file Detailed and updated instructions are given at http www eso org observing p2pp P2PP FC cookbook html 5 6 Guide Stars Policy Starting from P72 ESO applies the following policy regarding gu
37. illustrated in the example below FE Zoom Object NGC2243 1153 0 2440 5 Bitpix Low ooo High 15000 Auto Set Cut Levels sidi 68 VIMOS User Manual VLT MAN ESO 14610 3509 The way to assign one of these is the same for all types e in the image display click on the object you want to assign a special type That object must be in the catalog i e have a white circle around it exception new reference objects The white circle will be highlighted e in the catalog window under Modify Flags click on the button corresponding to the type you want to assign to the object e g you just clicked in the image on a object that you want to be a reference so click now on the button Ref curved slit is a special case described in more details below e in the catalog window the object will be highlighted You can check whether in the column FLAG the type was changed from S select able to the new type e g R for reference e repeat the above steps as often as you need After this operation you will have updated the FLAG column in you catalog You are ready to pass to Step 6 Be reminded that at this point all objects with X RADIUS gt 45 pix will be flagged as forbidden Note that instead of doing this interactively inside VMMPS you could have created earlier in the input catalog the column FLAG and assigned the right types except for curved sl
38. in X and Y according to the list of offsets 1 1 X Figure 4 5 Illustration of the VIMOS_img obs_Offset template The black dots represent the position of a star which was originally at the center of the field In this example the SKY option is selected and the telescope is moved in RA and DEC in the opposite direction of the offsets in the list so that the star moves in RA DEC according to the offset list 38 VIMOS User Manual VLT MAN ESO 14610 3509 4 6 2 VIMOS mos obs Offset The parameters of this template are Exposure time in seconds This is the integration time in seconds per exposure Filter The available filters are U B V R I z OS blue OS red GG435 GG475 and no filter The standard grism filter configurations are given in Table 2 3 Only standard filter grism combinations are allowed as indicated in Table 2 3 Other combina tions should be requested with a waiver Grism The available grisms are LR blue LR red MR HR blue HR orange HR red Return to Origin T F This parameter defines whether or not after a dithered set of ob servations the telescope will return at the position at beginning of the template This parameter is in general to be left in the default value T in service mode If another value is desired in service mode a waiver should be requested Number of Telescope Offsets This parameter defines the number of telescope offsets dur ing the template The number o
39. in this mask with yellow squares special objects are not marked any longer as such M Zoom Object NGC2243 x 136 0 2431 0 339 07 59 55 412 Ro 65535 Bitpix 16 Low 5000 High 15000 Auto Set Cut Levels 0 O You can use the button Plot Slits and Clear Slits to overlay the actual slits and expected spectral range 78 VIMOS User Manual VLT MAN ESO 14610 3509 F Zoom Object NGC2243 259 0 2428 0 E EE 327 07 59 57 125 10 40 07 01 2000 in 259 4 65535 16 000 SSS E Auto Set Cut Levels 4 Grid H Once you have made the last modifications you can move on to the next mask of the series as described above Choose Mask and once you are through with all masks proceed to Step 8 You are almost there VIMOS User Manual VLT MAN ESO 14610 3509 79 6 2 9 Step 8 Writing your final ADP you have succeeded Once you are happy with all slits in all masks for this quadrant click on Make final X ADPs where X indicates the number of masks you have defined and for which ADP files will be written A last pop up window will appear Choice i What do you want to do now Next Quadrant Exit VMMPS and ask you whether you want to restart a VMMPS pass e g with the next quadrant exit VMMPS after saving all results go back t
40. might become less precise than with a well prepared catalog including reference stars on the same system as your scientific targets The procedure to pick new reference stars is a little different than the one described above since obviously you cannot click on a highlighted object in the image display In order to select new reference stars just click on the button New Ref This will pop up a Pick New Object window see below Move the cursor in the image display onto the object you want to select and click Then select ENTER in the panel below to enter the object in the catalog E Pick New Object 1 Area of image to be examined Image Statistics Image X 797 8 Image Y 1600 7 o 08 00 04 627 db 10 42 56 76 Equinox 2000 70 VIMOS User Manual VLT MAN ESO 14610 3509 And you have the opportunity to change from the default values all other entries for all columns Enter Object 1 ALPHA VIMOS 08 00 04 627 DELTA VIMOS 10 42 56 716 ALPHA SKY O DELTA SKY O XIMAGE 797 8 0 YIMAGE 1600 7 0 A IMAGE po B IMAGE po THETAIMAGE O ssid El gt The new object appears at the bottom of your object list in the catalog window Note that the task is called New Ref because this is the only case we consider useful but in principle once the object is in the catalog you could change its flag to any allowed value Compulsory objects You can flag a few objects as
41. the following lamps e Flatfield lamps QTH1O0 halogen lamp for imaging screen flats in VRIz and MOS spectroscopic screen flats in LR red and blue QTH50 halogen lamp for imaging screen flats in U B MOS screen flats in MR HR red and blue and all IFU screen flats e Arc lamps He Ar Ne In the web an updated atlas of spectral lines for the different grisms can be found 2 7 Flexures The passive flexure compensation of VIMOS is optimized to reach a reasonable compromise in every position of the Nasmyth rotator An astatic compensator system is installed in quadrants 2 3 and 4 Image motion due to instrument flexures under gravity are currently within approximately 2 pixels for the channels 2 3 and 4 and 3 pixels for channel 1 for the whole rotator range Notice that these flexures can affect image quality spectral resolution wavelength accuracy sky subtraction etc See Sect 3 2 for recommendations on how to deal with fringing and flexures Chapter 3 Observing with VIMOS All observations with VIMOS are done via observing blocks OBs OBs consist of one acquisition template including target information followed by observing templates related to the observing mode The users will fill out the parameter fields keywords of the templates e g grisms filters etc All the preparations are done with the Phase II proposal preparation tool p2pp In addition VIMOS masks ha
42. time MOS Flat 5 All used masks Screen Arcs 1 Daily Day time Dispersion coeff 0 3 pix All used masks Screen Arcs 1 Attached to science Dispersion coeff 0 3 pix All used masks OB with HR or LR blue Specphot 4 See text Night time Response 10 All grism filter Standard Star quadrants function setups used 1 Internal accuracy not considering instrument flexures see Sect 2 7 IMPORTANT NOTE The execution time for all attached night time calibrations screen flats and arcs is subtracted from the total allocated time 3 4 10 MOS mode Exposure Time Calculator The approximate limiting magnitudes in MOS mode can be obtained from the exposure time calculator avail able on the ESO WEB pages http www eso org observing etc 3 5 Integral Field Unit IFU 3 5 1 Acquisition accuracy In IFU mode acquisition is blind i e limited by the accuracy of the telescope pointing 3 accuracy 3 5 2 Dithering jitter pattern With the large field of view of the VIMOS IFU techniques equivalent to shift and add classically used in imaging are a possible mode of operations Dithering jitter pattern is a list of differential pointing positions around a central position Several short images with exposure times set to have sky background limited exposures are taken at each position of a dithering pattern which are combined to reconstruct an image with the total required exposure time This allows to el
43. two catalogs the better the result of the cross correlation i e the transformation from RA DEC to pixels will be Since the objects will be used for cross correlation their position in pixel coordinates shall be as good as possible Therefore make sure that you selected bright S N gt 10 unsaturated if possible point like objects on the VIMOS pre image This comparatively short list of objects shall be written in an ASCII file with the mandatory columns in upper case and in the following order e ID an identifier which must be unique and integer number e X IMAGE the x coordinate in pixels on the VIMOS pre image e Y IMAGE the y coordinate in pixels on the VIMOS pre image Any other column is allowed but will be ignored and not carried over to the output catalog of the cross correlation see Step 2 The example of a VIMOS pre image catalog is given in Section 6 4 56 VIMOS User Manual VLT MAN ESO 14610 3509 Getting your VIMOS catalog into the right format Assuming that you are in case 2 you only need to preparea VIMOS catalog The VIMOS catalog can e either be obtained as an output of the cross correlation task in which case you do not have to worry it will have the right format e or be produced directly by the user that s you from the VIMOS pre image The mandatory columns are in upper case and in the following order e ID an identifier which must be unique and integer number e X_IMAGE the x
44. written and you could proceed without changes to Step 8 Optionally if you have the feeling that you should modify a few slits proceed with this Step but be careful you are about to try to optimize an optimization The window lists all objects that have been allocated slits in this mask You can now do the final careful fine tuning by unselecting some slits Unsel and or adding some slits New Slit following the procedure that should start to be familiar to you by now interacting with the display finish by pressing Enter in the Pick Object window The new slit will be created with default values the slit width will be the one that you defined in Step 6 during the automatic slit assignment the slit length defined by the X_RADIUS of the new object added to the minimum sky region defined in Step 6 Note that in low resolution slits that overlap in dispersion direction get common slit width in Step 6 to facilitate sky subtraction with second order contamination but this is not automatically done here Also there is no check for slit overlap so be extremely careful You can edit modify the values for the new object A new row with that object will appear at the end of the catalog in main catalog window and the entries for this object can be modified by you To do this click on the row with the new object that gets highlighted then and go to the pull down menu Edit to choose Edit selected object This open
45. 0 arc seconds acquisition box in quadrant 1 and then centered by the Night Time Support Astronomer IMPORTANT the user have to provide coordinates accurate enough to have the selected standard visible in the acquisition box Note differently to the MOS science acquisition where the coordinate of the field come from the ADP files produced by VMMPS the coordinates of the standard star should be set by the user in the target sub window Note the rotator angle is fixed for this template at 90 corresponding to the set of slits in the masks being oriented N S The parameters of the template are e Exposure time seconds This is the integration time for the acquisition image that will be 34 VIMOS User Manual VLT MAN ESO 14610 3509 taken through the mask to check its positioning Filter This filter is the one to be used for the acquisition image It is recommended to choose the right combination filter exptime to avoid the saturation of the star in the acquisition image The available filters are U B V R I z OS blue OS red GG435 GG475 and no filter Optional additional velocity moving targets in alpha and delta Additional Velocity RA and Additional Velocity DEC This velocity should be expressed in arcsec sec These parameters are mostly intended for imaging and possibly IFU programs of moving targets and a priori unlikely to be of much use in MOS mode If no additional velocity is needed these parameters should be le
46. 00000 Guide Star Dec INS ADP1 file name Name of 1st quadrant ADP File INS ADP2 file name Name of 2nd quadrant ADP File INS ADP3 file name Name of 3rd quadrant ADP File INS ADP4 file name Name of 4th quadrant ADP File TEL TARG EQUINOX 2000 3000 Equinox TEL TARG EPOCH 2000 3000 Epoch TEL TARG PMA 10 10 proper Motion Alpha TEL TARG PMD 10 10 proper Motion Delta TEL TARG ADDVELALPHA 15 15 Additional Velocity RA TEL TARG ADDVELDELTA 15 15 Additional Velocity DEC VIMOS ifu acg Preset Keyword Range Label in p2pp DET WIN1 UIT1 1 1000000 Exposure time seconds INS FILT NAME UBVRIz Filter OS red OS blue GG435 GG475 INS GRIS NAME LR_blue LR_red MR HR_blue Grism HR_orange HR_red TEL TARG ALPHA RA of the Field Center TEL TARG DELTA DEC of the Field Center TEL TARG EQUINOX 2000 3000 Equinox TEL TARG EPOCH 2000 3000 Epoch TEL TARG PMA 10 10 proper Motion Alpha TEL TARG PMD 10 10 proper Motion Delta TEL ROT OFFANGLE 180 180 Rotator on sky TEL TARG OFFSETALPHA 3600000 3600000 Alpha Offset TEL TARG OFFSETDELTA 3600000 3600000 Delta Offset TEL AG GUIDESTAR SETUPFILE CATALOGUE Get Guide Star From TEL GS1 ALPHA 0 240000 Guide Star RA TEL GS1 DELTA 900000 900000 Guide Star Dec INS IFUE NAME 0 33 0 67 IFU magnification in arcsec fiber INS IFUS MODE FT IFU Shutter TEL TARG ADDVELALPHA 15 15 Additional Velocity RA TEL TARG ADDVELD
47. 1251 0 0008 27 1317 302 113 621 LLO DIAS 3 6 2 4142 0 0010 28 926 796 142 882 3 188 2 830 635 9 0968 0 0004 29 832 140 129 522 27100 Za F138 17 4 4509 0 0005 30 975 537 113 508 2 163 2 068 10 8 3 0277 0 0017 86 VIMOS User Manual 6 4 4 Example of an ADP file Your final ADP file should look something like this It starts with a few PAF INS keywords defining the file itself In then adds the crucial telescope pointing parameters before describing for which instrument config uration the ADP has been created It then gives the most important part the CCD to Mask transformation Only then comes the part describing first the reference objects and then all slits defined for this mask with all curved slits appearing at the very end and an example is appended here O Q H a ANNnNNNN N HO OH WH WH H H 22222 24 H FU TP DA TE PAF PAF PAF PAF PAF PAF PAF PAF PAF PAF PAF PAF PAF m TA T Ta mn Ti m mn Ta mn mr mr mn 4 CRTE NAME vmmps 3 22 CRTE DAYTIM 2004 05 12T15 50 59 001 LCHG NAME LCHG DAYTIM CHCK NAME CHCK DAYTIM CHCK CHECKSUM 954768746 HDR END INSTRUME VIMOS CON QUAD 1 FOCU1 TEMP 12 31496 ADF TYPE MOS ADF VERSION 3 22 ADF UNIT PIXEL ADF ID wfil6_vm_LR_Red_M101 adp ADF COMMENT MASK1 ID 1 1 FILE DIRNAME SINS_ROOT SINS_USER ADEF HDR START TYPE param
48. 3 Mask 4 Channel 3 Channel 4 IFU head View from the telescope Modules of the lines B C D for mask IFU head details of the fiber modules Low transmission fiber blocks are marked with white rectangles For rotator angle 0 North is to the right East to the top Mask 2 Mask 1 Line D Sac IAS ton ae al me Ps a of the 80 For all modules of thel Hs 4 mask 1 Sie dae oe AA gt Line A EBEE ER ap eae or wae AA For all modules of the 80 For all modules of thel mask 3 80 mask 4 LM DT sas Sa sa r lneB Lite C 7 3 Tas Tila TE nel Line D3 3 ee ee Mask 4 Mask 3 View from the telescope Figure 2 7 IFU mode fibers numbering on the masks VIMOS User Manual VLT MAN ESO 14610 3509 15 Table 2 6 Integral Field Unit spatial characteristics Spatial sampling Field of view Number Pseudo slits Grism Shutter arcsec fibre arcsec of fibres per quadrant LR blue LR red OFF 0 67 fibre 54 x 54 80 x 80 4 LR blue LR red ON 0 67 fibre 27 x 27 40 x 40 1 LR blue LR red OFF 0 33 fibre 27 x 27 80 x 80 4 LR blue LR red ON 0 33 fibre 13 x 13 40 x 40 1 MR HR blue HR orange HR red ON 0 67 fibre 27 x 27 40 x 40 1 MR HR blue HR orange HR red ON 0 33 fibre 13 x 13 40 x 40 1 Table 2 7 Spectral characteristics in IFU mode Grism Default Order Spectral range Spectral Res Dispersion Spectral sorting filter
49. ARG EQUINOX 20007 ILLAR MANL ME INS ADF GRISM NAME PMA IMS DF GRISM SPECT EN IS 12 INS ADF SICYPALG 2 INS REF MO 2 ny Enter ilu nwn ti etree fnras ser mil NI ats INS SHUNO 2 IMSS HUT PO SL U INS SHIN PO SH 21 RIF INS SHIP POS PIAM IMS SHU2PO SH 21107 Ds Upzzba Care LEP PIO LLC SILO SY IPE 11 RI TJURRA L e PRO CCD MASK TEMP 40259544 fo PR CO SKA O 132 3336671 03 ler ert a fin PAC REA AEN AO Figure 4 3 P2PP VIMOS ADP browser window e ADP files 1toADP file 4 These 4 parameters are the names of the ADP files produced by VMMPS The files 1 to 4 correspond to the 4 quadrants of the instrument and should be set in the right order When selecting an ADP file entry in P2PP a browser window opens up allowing to locate the file on the local disk This window is presented in Figure 4 3 4 5 3 VIMOS_mos_acq_Standard This template is used for the acquisition in mode MOS using the specially designed set of calibrations masks provided by Paranal This set of masks contains a series of slits of different width that can be used for all calibrations that requires the use of a standard star i e spectrophotometric radial velocity or metallicity standard Since the template is using a pre defined set of masks no ADP need to be provided by the user No reference stars are used for the acquisition The standard star whose coordinate are provided by the user in the template will be offset in the 10x1
50. ELTA 15 15 Additional Velocity DEC VIMOS User Manual VLT MAN ESO 14610 3509 105 VIMOS img obs Offset Keyword Range Label in p2pp DET WIN1 UIT1 1 100000 Exposure time seconds INS FILT NAME UBVRIz Filter SEQ NEXPO 1 1000000 Number of exposure per telescope offset SEQ NOFF 1 1000000 Number of telescope offsets SEQ RETURN FT Return to Origin T F SEQ OFFSET COORDS SKY DETECTOR Offset Coordinates SEQ OFFSET1 LIST List of offsets arcsec in X or RA SEQ OFFSET2 LIST List of offsets arcsec in Y or DEC SEQ CATG PRE IMAGE SCIENCE Observation Category VIMOS mos obs Offset Keyword Range Label in p2pp DET WIN1 UIT1 1 100000 Exposure time seconds INS FILT NAME UBVRIz Filter OS red OS blue GG435 GG475 INS GRIS NAME LR_blue LR_red MR HR_blue Grism HR orange HR red SEQ NEXPO 1 1000000 Number of exposure per telescope offset SEQ NOFF 1 1000000 Number of telescope offsets SEQ RETURN FT Return to Origin T F SEQ OFFSET1 LIST List of offsets along the slit arcsec SEQ OFFSET2 LIST List of offsets perpendicular to the slit arcsec VIMOS ifu obs Offset Keyword Range Label in p2pp DET WIN1 UIT1 1 100000 Exposure time seconds INS FILT NAME UBVRIz Filter OS red OS blue GG435 GG475 INS GRIS NAME LR blue LR red MR HR blue Grism HR orange HR red INS IFUE NAME 0 33 0 67 I
51. FU magnification in arcsec fiber INS IFUS MODE FT IFU Shutter SEQ NEXPO 1 1000000 Number of exposure per telescope offset SEQ NOFF 1 1000000 Number of telescope offsets SEQ RETURN FT Return to Origin T F SEQ OFFSET COORDS SKY LENSLET Offset Coordinates SEQ OFFSET1 LIST List of offsets arcsec in X or RA SEQ OFFSET2 LIST List of offsets arcsec in Y or DEC 106 VIMOS User Manual VLT MAN ESO 14610 3509 VIMOS_img_cal_Photom Keyword Range Label in p2pp DET WIN1 UIT1 1 100000 Exposure time seconds INS FILT NAME UBVRIz Filter SEQ NEXPO 1 1000000 Number of exposure per telescope offset SEQ CAL FLAG 14 1 or 4 quadrants VIMOS img cal Astrom Keyword Range Label in p2pp DET WIN1 UIT1 1 100000 Exposure time seconds INS FILT NAME UBVRIz Filter SEQ NEXPO 1 1000000 Number of exposure per telescope offset SEQ CAL FLAG 14 1 or 4 quadrants VIMOS_mos_cal_NightCalib Keyword Range Label in p2pp SEQ FLATFIELD FT Night Flat Field SEQ ARC FT Night Arc SEQ FLATFIELD NEXPO 1 1000000 No of scrrenflats VIMOS mos acg Standard Keyword Range Label in p2pp DET WIN1 UIT1 1 1000000 Exposure time seconds INS FILT NAME UBVRIz Filter TEL TARG EQUINOX 2000 3000 Equinox TEL TARG EPOCH 2000 3000 Epoch TEL TARG PMA 10 10 proper Motion Alpha TEL TARG PMD 10 10 prope
52. Manual VLT MAN ESO 14610 3509 71 Curved slits You have the possibility to define curved or tilted slits To do so click on the button Curved This will pop up the Curved Slit window essentially a Pick Object skycat window with several special features Slit Width arcsec 10 DID Rotate Angle degree 0 LT Image Statistics Image X 12683 Image Y 1237 4 08 00 11 180 d 104411 29 Equinox 2000 Once you clicked on the object in the image it appears in the Curved Slit window and you can define the curved slit To do this click in the little display to define the points through which the curved slit should pass start with a point centered on your object maybe Once you have defined a few points click on View Fit and the slit will appear Note that at any given x the Ay is kept constant to warranty constant slit width dispersion along the slit You can modify the slit width by using the slit width bar or type in directly the value in the associated box and click View Fit again 72 VIMOS User Manual VLT MAN ESO 14610 3509 If you wished a straight slit just click Straighten Rotate after having clicked View Fit If you wish to give the slit a given position angle use the Straighten Rotate Angle bar or type in directly the value in the associated box and click on Rotate Remember that in normal pre imaging North is left x on detecto
53. Toulouse France e Osservatorio Astronomico di Capodimonte Napoli Italy e Istituto di Fisica Cosmica e Tecnologie Relative Milano Italy e Osservatorio Astronomico di Brera Milano Italy e Istituto di Radioastronomia Bologna Italy e Osservatorio Astronomico di Bologna Bologna Italy VIMOS User Manual VLT MAN ESO 14610 3509 Chapter 2 Instrument Characteristics FOLDING MIRROR PUPIL RELAY LENS WAAAY NN co SN SA CAMERA ug VIMOS Scale 0 09 ESO 04 Jul 02 Figure 2 1 VIMOS Optical layout 2 1 Overview VIMOS is the Visible Multi Object Spectrograph for the Very Large Telescope VLT of the European Southern Observatory ESO This instrument has been built to provide the ESO community with a wide field spectrograph with high throughput and multiplex dedicated to deep surveys VIMOS operates in the 0 37 1 0 um domain in three main observing modes direct imaging IMG multi slit spectroscopy MOS and integral field spectroscopy IFU Because of the large field of view VIMOS optical path is split into four channels The four quadrants of the instrument are operated in parallel i e it is not possible to mix modes or filters or grisms between quadrants The field of view of the four channels is 4 x 7 x 8 in IMG and MOS and up to 54 x 54 in IFU mode in low resolution spectroscopy It provides an image scale of 0 205 pixel in MOS and 0 67 resolution element in IFU mode Each of the 4 ch
54. Version 79 1 Substantial chances to the description of the instrument field of view Changes by S Bagnulo and M Rejkuba Dr S L Morris is acknowledged for having improved Fig 2 6 An error in Table 5 has been corrected 1 5 4 Version 80 0 Some changes in the night time calibration plan 1 5 5 Version 84 0 VMMPS and Guidecam documents were merged into this manual All the links have been updated to reflect the 2008 changes in the ESO web 1 5 6 Version 85 0 This manual is for P85 preparation As of this writing 1 Sep 2009 there is an ongoing project that aims to upgrade the instrument It is forseen that the detectors will be changed by new deep depletion e2v detectors which will increase the red response and reduce fringing The changes to the instrument will imply that once VIMOS is upgraded current MOS OBs might need to be redone with new pre image Also the ETC for the current detectors will give discrepant results specially redward of 700nm Please look for information in the instrument web pages We apologize for the problems that this project will generate to the users during P85 VIMOS User Manual VLT MAN ESO 14610 3509 1 6 Acknowledgments The following institutes have participated to the development of VIMOS e Laboratoire d Astrophysique de Marseille Marseille France e Observatoire de Haute Provence Saint Michel 1 Observatoire France e Laboratoire d Astrophysique de l Observatoire Midi Pyr n es
55. ad out Mode RON e rms K e7 adu CCD 1 225kpxs low gain IMG mode 5 3 1 70 CCD 2 225kpxs low gain 5 2 1 86 CCD 3 225 kpxs low gain 5 3 1 95 CCD 4 225kpxs low gain 4 9 1 80 CCD 1 225kpxs high gain MOS and IFU modes 4 3 0 51 CCD 2 225kpxs high gain 4 6 0 56 CCD 3 225kpxs high gain 4 7 0 57 CCD 4 225kpxs high gain 4 3 0 52 RON and conversion factor monitoring is available through the QC1 WEB pages 2 5 4 Fringing With the z Gunn and Bessel J filters the fringing amplitude is around 7 in imaging and in spectroscopy the amplitude of fringing is of the order of 7 8 at maximum Despite this relatively strong fringing it is important to note that the structure is quite stable and dithered images taken in a sequence can easily remove the structure see Sect 3 2 2 5 5 Shutters The shutter one for each CCD camera guarantees uniform illumination of the CCD to the 1 level or better for exposure times as short as 1 sec the shortest possible exposure time 2 5 6 More information More updated information on detector characteristics cosmetics and performance on sky at http www eso org projects odt http www eso org observing dfo quality 18 VIMOS User Manual VLT MAN ESO 14610 3509 2 6 Calibration Units VIMOS has three calibration units illuminating a calibration screen at the back of the Nasmyth shutter closing the Nasmyth tunnel Each unit has
56. age catalog ascii Select VIMOS Pre image File fits Cross Correlate This window asks you to input in that order the catalogs and the image Just click from top to bottom and follow the instruction Once you have filled the last item e that window will look as shown below e the selected VIMOS pre image will appear in the display K VIMOS Cross Correlation sequence Select Contributed catalog ascii home mkissler VIMOS VMMEPS exp n1316 contributed cat Select VIMOS Pre image catalog ascii fhome mkissler VIMOS VMMPS_exp n1316_preimage cat Select VIMOS Pre image File fits v home mkissler VIMOS VMMPS_exp n 1316_image fits Cross Correlate and after you have clicked on the button Cross correlate e the above window will disappear and e the window vmmps_cross will pop up VIMOS User Manual VLT MAN ESO 14610 3509 61 You will then get something like this K Skycat version 2 6 5 fomaxQ1 fits 1 Object Equinox Min Max Bitpix Low High Zoom 35 37 59 49 Auto Set Cut Levels B nati 8 WS Grid Scale ma Z 2 S 2iul 8 vmmps cross Markus Target 1484 0 963 0 148601 03 38 24 581 Contributed cat E fhome mkissler VIMOS VMMPS OId vmmps_testfornax_contribu VIMOS Pre image cat home mkisslerVIMOS VMMPS Old vmmps_test fornax_preimag VIMOS Pre image home mkissler VIMOS VMMPS Old vmmp
57. all dither positions for offset patterns used in the OBs must fit inside a 30 x 30 size box If larger offsets are necessary users need to prepare separate OBs and use appropriate guide star for each of them 3 0 4 Telescope and Instrument Focus The telescope focus is automatically set by the active optics system No intervention is required by the ob server Defocusing of the telescope is not possible during the observations The instrument focus is corrected automatically for the different thickness of the various filters and for temperature variations autofocus 3 1 Atmospheric Dispersion VIMOS is not equipped with Atmospheric Dispersion Corrector in none of its modes The impact of atmo spheric dispersion will be mostly noticed in MOS mode In imaging some image elongation may be noticed at high airmasses in the U or B band In IFU the effect will mostly be noticed with the LR_blue grism and with the 0 33 fiber sampling In MOS mode the effects can lead to severe slit losses if some precautions are not taken To minimize atmospheric dispersion effects at high airmass and assuming that the observations are performed close to meridian the slits need to be oriented N S forcing the rotator angle to be set at 90 This rotator angle is the default one to be used for pre imaging and the same rotator angle will be used during spectroscopic follow up The VIMOS operational scenario foresees to carry out MOS observations as close as p
58. and e EITHER for each quadrant a VIMOS catalog e ORacontributed catalog it can be one catalog including objects on all 4 quadrants or be four catalogs one per quadrant together with for each quadrant a VIMOS pre image catalog The format of the catalogs All catalogs accepted by VMMPS have plain ASCII format The file name should not use the extension dat as this causes the program to crash Use of cat or data should work Some example are given in Section 6 4 The input format is e a header line with column names in upper case There is no preferred order for the columns but see below for mandatory and reserved columns and names The first line is interpreted as the header line Header entries are separated by any number of blanks or tabs A lt return gt marks the end of the header line e the data sorted in columns Columns on a given row are separated by any number of blanks tabs The number of columns and their order is defined by the number of entries and their order in the header No empty field is allowed you will get a friendly warning if some are present The first row after the header line defines the beginning of the data the last row defines the end of data Each row must end with a lt return gt Note that no blank lines are allowed in the catalogs and you will get a friendly warning if any is present 54 VIMOS User Manual VLT MAN ESO 14610 3509 Getting your contributed catalog into the r
59. annels has a 2048 x 4096 pixels EEV CCD 44 82 backside illuminated single layer coating with the 4k pixels being used along the dispersion to maximize the spectral coverage VIMOS is installed on the Nasmyth B focus of UT3 Melipal The VIMOS mechanical and optical characteristics are 5 VIMOS User Manual VLT MAN ESO 14610 3509 Table 2 1 VIMOS opto mechanical characteristics Instrument Location Opto mechanical layout Wavelength coverage Detectors Spectral Resolution Filters Nasmyth B VLT UT3 Melipal 4 beams each a complete focal reducer F 1 88 output 0 37 to 1 microns 4 x 2048 x 4096 15 um pixel R 180 to 2500 1 arcsec slit 10 per channel U BVRIz OS red OS blue GG435 GG475 170mm diameter Grisms 6 per channel LR red LR blue MR HR blue HR orange HR red 1 Flexures Passive compensation motion of 2 pixels over 360 rotation Masks 10 masks simultaneously loaded in instrument practical maximum per channel 2 Slits of any position and shape width gt 0 6 length lt 30 Multiplex 840 simultaneous slits 10 long at R 200 210 simultaneous slits 10 long at R 2000 2500 Integral Field Unit 54 x 54 field 6400 fibers with 0 67 sampling 27 x 27 field 6400 fibers with 0 33 sampling 11 From October 2005 a set of four new and more efficient HR red VPHG grisms is installed and available in the 4 channels 2 Some restrictions apply in operations curren
60. arcseconds The offsets refer to the target so that the target is offset by the requested amount by moving the telescope in the direction opposite to the offset values Examples are provided further down in the description of the templates e Only some combinations of filters and grisms are allowed See Sect 2 3 and Table 2 3 4 4 List of templates Table 4 1 lists the VIMOS templates Table 4 1 Science and Nighttime Calibration Templates Type Name VIMOS _img_acq_Preset Acquisition VIMOS mos acq Mask templates VIMOS mos acq Standard VIMOS ifu acg Preset Science VIMOS img obs Offset templates VIMOS mos obs Offset VIMOS ifu obs Offset VIMOS img cal Photom VIMOS img cal Astrom Calibration VIMOS mos cal NightCalib templates VIMOS mos cal Standard VIMOS ifu_cal_NightCalib VIMOS ifu cal TwFlat VIMOS ifu_cal_Specphot 4 5 Acquisition templates 4 5 1 VIMOS img acq Preset This template is used for acquisition of a field in imaging mode for both imaging and pre imaging OBs Figure 4 1 shows the P2PP window with an example of a pre imaging Observing Block OB The coordinates of the target have to be entered in the Target window at the bottom of the P2PP window The parameters for this template are the following e Filter This filter should be the same as for the subsequent imaging template The available filters are U B V R I z e Rotator on sky This parameter defines the orientation
61. as well In the USNO at ESO pane the maximum number of objects can be changed to either limit or increase the number of stars to be displayed whenever a value is changed and entered a new search takes place and the results are displayed on the images while the updated list of stars appears on the Search Results panel Pressing the Search button after changing more than one value will also start a new search and display the results 5 4 Selecting the Guide Star To select a guide star Click with the left mouse button on one of the white circles identifying the USNO stars This opens a small panel asking Move to the selected guide star Pressing Accept will move the guide probe to the star Vignetting of the VIMOS field of view takes place whenever the guide probe yellow intercepts the VIMOS field of view green rectangle If there is vignetting it is possible to select another star and to repeat the operation until a suitable guide star is found The guide probe can be positioned on a given guide star in 2 positions called positive and negative POS and NEG This is referenced to as Alternate position By selecting the corresponding button inthe Guide Probe Settings panel figure 5 2 and pressing the Apply button the guide probe will be positioned on the same star on its alternate position This option may allow to reduce or even remove the vignetting that may be present in the other position Once a suitable guide star
62. ctor for each grism and default order sorting filter for the slits located at three different positions in the field of view With low resolution grisms the spectral coverage is independent of the position of the slit VIMOS User Manual VLT MAN ESO 14610 3509 11 Table 2 3 Standard grism filter combinations for MOS and IFU modes Grism Filter Default Allowed LR blue OS blue Free LR red OS red Free MR GG475 OS red OS blue HR blue Free HR red GG475 HR orange 66435 The grism filter configuration MR OS blue is not supported by the pipeline 2 3 2 Spectral resolution The spectral resolution obtained with a 1 slit width with the various grisms is given in Table 2 4 2 3 3 Multiplex characteristics A particular feature of the MOS mode is the possibility of stacking multiple layers of slits along the dispersion direction This is only possible with the low resolution grisms up to four slits along the dispersion direction and the intermediate resolution grisms up to two slits for which the spectra are short enough in number of pixels to allow stacking With the high resolution grisms only one slit can be placed along the dispersion direction However please note that in the multi layer mode there is some order overlap the second order of one slit may overlap with the first order of the adjacent slit There is also 0 order contamination between different layers of sli
63. e T in service mode If another value is desired in service mode a waiver should be requested e Number of Telescope Offsets This parameter defines the number of telescope offsets dur ing the template The number of exposures taken at each telescope position is determined by the next parameter Number of exposures per telescope offset The pattern of off sets is defined in the parameters List of offsets arcsec in X or RA and List of offsets arcsec in Y or DEC Offsets are defined relative to the previous position 36 VIMOS User Manual VLT MAN ESO 14610 3509 e Number of exposures per telescope offset This parameter defines how many expo sures are taken at each offset position e Offset coordinates This parameter defines the coordinate system used to define telescope offsets If the SKY option is selected telescope offsets are in RA and DEC if DETECTOR is selected telescope offsets are in X and Y on the detector In both cases the offsets are given in arcsec e List of offsets arcsec in X or RAandList of offsets arcsec in Y or DEC List of offsets between exposures Offsets are defined relative to the previous position The off sets are defined in RA DEC or X Y on detector depending on which option is selected for the Of fset coordinates field If the first image is to be taken at the preset coordinates the first set of offsets should be 0 0 If there are less offset values than t
64. e VIMOS calibrations consists of using a pinhole mask to determine accurately the transformation between millimeters on mask and coordinates on the CCD we know at which mm we cut the holes in the mask and we measure the x y coordinates of the holes on the image processed by the ESO pipeline This transformation is stored and updated on the instrument workstation Now when your VIMOS pre image gets taken this transformation valid at that particular moment is stored in the header of your VIMOS pre image Thus with the help of that transformation you or rather VMMPS know how to go from the x y coordinates of that image to position in mm on the mask i e position on the focal plane The combination of the transformation in that header and the coordinates in that image allows to determine the precise mm coordinates for the mask Should you use transformation and x y from different images the result would not be correct anymore Thus the importance to derive the coordinates from exactly the image that will be fed to VMMPS and from which the transformation will be taken 58 VIMOS User Manual VLT MAN ESO 14610 3509 6 2 2 Step 1 What is your starting point Are your sure you fulfilled Step 0 If you have not suffered at least a little bit while preparing your catalog if you have not thought twice whether you had the right objects in there there is a good chance that you will suffer a serious headache before Step 8 So take your time re thinkin
65. e advantage is that these latter coordinates can now be transformed into mm in the focal plane i e mm coordinates on the mask by using the CCD to Mask transformation present in the header of the pre image VIMOS User Manual VLT MAN ESO 14610 3509 63 6 2 4 Step 3 Starting VMMPS for mask definition At the beginning of this step make sure that your display is blank safest way by selecting Clear in the File pull down menu of skycat or be sure that the image displayed is indeed the pre image that you want to use for this step You have your VIMOS catalog ready Then go ahead and selected in the main window from the pull down menu VIMOS MPS the task Assign slits from a Vimos catalog produce ADP You will be asked to select your VIMOS catalog and the associated VIMOS pre image The latter will appear in the display and all objects in your catalog will be marked as white circles The VIMOS catalog will be shown in a separate window Your screen will look like this Search Options Object Name Equinox 2000 03 38 16 835 d 35 37 06 85 Min Radius 0 0 Max Radius 5 45 Max Objects 10000 Select Area Set From Image Search Results 134 VIMOS DELTA VIMOS 76600 ISR 00128 91300 37 02 00137 97800 36 19 00438 13400 Sonido 00507 12800 40 54 00506 50200 40 54 00587 94300 39 56 00732 85400 41 15 00905 89000 35 32 01087 72400 36
66. e stars for the IFU mode but only for the IMG and MOS mode of VIMOS Guide Star RA and Guide Star DEC Coordinates of the guide star when the SETUPFILE option of the Get Guide Star From field is selected Optional additional velocity moving targets in alpha and delta Additional Velocity RA and Additional Velocity DEC This velocity should be expressed in arcsec sec If no additional velocity is needed these parameters should be left to their default values 4 6 Science templates 4 6 1 VIMOS img obs Offset This template is used for Imaging mode observation both for Science and Pre imaging The parameters of this template are the following e Exposure time in seconds This is the integration time in seconds per exposure e Filter The available filters are U B V R I z In order to produce a valid OB the filter in the first observation template following the acquisition template should be the same as the one selected in the acquisition template For pre imaging the use of R filter is mandatory e Return to Origin T F This parameter defines whether or not after a dithered set of ob servations the telescope will return to the position at the beginning of template As an example this parameter should be set to T when the aim of the OB is to execute multi color imaging observations with the same pattern of offsets on the same field using different templates This parameter is in general to be left to its default valu
67. eady a VIMOS catalog Step 3 Starting VMMPS for mask definition O Step 4 optional re arranging your VIMOS catalog Step 5 First pass defining special objects Have you been careful and defined at least 3 reference objects per quadrant Step 6 The automatic slit assignment your first ADP draft Spend some time thinking of your parameters Tip select only the wavelength range you really need O Step 7 optional Fine tuning last corrections Only go through this step if you are sure to know what you are doing Step 8 Writing your final ADP And remember never to edit this file by hand Make finding charts after pressing Plot Slit button by selecting File gt Make Finding Chart menu YOU ARE DONE Appendix Chapter 7 VIMOS Filters Table Al lists the characteristics of the VIMOS filters The transmission curves are given in the following figures Table Al Characteristics of the VIMOS filters Updated filter characteristics can be found in http www eso org sci facilities paranal instruments vimos inst imaging html Filter Ay nm FWHM nm U 370 50 B BESS 430 97 0 V_BESS 546 89 0 R_BESS 648 5 130 0 I 830 80 0 z GUNN 950 160 GG475 edge filter high pass gt 475 nm GG435 edge filter high pass gt 435 nm OS red box filter band pass 550 950 OS blue box filter band pass 370 670
68. ed value of 13 5 Below 11 arminutes i e within the green circle the Nasmyth field of view is vignetted by the tertiary mirror M3 of the telescope Therefore the aberrations of the telescope cannot be measured with the same accuracy In some cases this may degrade the image quality Magnitude range The default minimum and maximum values are 11 and 13 5 whereas the minimum and maximum permitted values are 10 and 14 With the faintest guide stars some degradation of the active optics correction might take place depending on seeing airmass Moon possible extinction by thin cirruses and position of the guide star in the field of view vignetting beyond 11 arcminutes To VIMOS User Manual VLT MAN ESO 14610 3509 47 Note Guide Probe Settings E Show State Guide Star F Automatic Image Load A Catalog Selection RA F Show Probe Dec F Show Detector FT Show Fields 3 Altemate Position Instrument Instrument Selection Currently Selected vimostovIMOS Telescope Guide Probe Preset RA 0 00 00 0 0 00 00 0 RA Preset Dec 0 00 00 0 0 00 00 0 Dec Rot on sky deg foo 90 0 Adapter deg Tum Table deg nninninn nnn J2000 Apply Get Guide Star Coonds Close Figure 5 2 Guidecam the Guide Probe Settings panel the extent this is possible stars brighter than 13 5 magnitude should be chosen Too bright objects may result in poorer correction
69. emission line galaxies will probably not allow you to do a nice cross correlation with the VIMOS pre image catalog you might want to add a few V 12 16 mag stars Run your favorite source detection algorithm on the original pipeline processed VIMOS pre image Make sure that you retain only point source with S N gt 20 or so and store all this in a VIMOS pre image catalog Make sure that you prepared the three above ingredients according to Step 0 and move now to Step 2 VIMOS User Manual VLT MAN ESO 14610 3509 59 Your catalog comes from a VIMOS pre image the VIMOS catalog case e Jump to Step 3 If you are sure that you have a VIMOS catalog for each quadrant fulfilling the requirements of Step O just identify the corresponding associated VIMOS pre image for each of the 4 quadrants You are ready to jump right into the mask definition move to Step 3 60 VIMOS User Manual VLT MAN ESO 14610 3509 6 2 3 Step 2 Transforming your contributed catalog into a VIMOS catalog This is a necessary step but quite painless if you followed the instructions of Step 0 From the pull down menu VIMOS MPS see Step 1 select the task Cross correlate Contributed and VI MOS pre image catalogs You will see popping up the following VIMOS Cross Correlation sequence window here under KDE Linux K VIMOS Cross Correlation sequence Select Contributed catalog ascii Select VIMOS Pre im
70. ent wavelength ranges and dispersions is available in MOS mode Order sep arating filters are available to eliminate the overlap for a given slit between orders 1 the order used for science and order 2 always present on the detector This is done by restricting the wavelength range of a particular grism to less than one octave in wavelength The Oth order contamination is present only in multi layered mode i e when observing with the LR and the MR grisms Table 2 3 indicates the recommended and allowed grism filter combinations Any other combinations of grisms and filters should be requested with a waiver Defining in the OBs combinations not allowed and for which a waiver was not requested will result in these OBs being rejected by the User Support Department ESO will not accept requests for user s supplied grisms or filters for VIMOS Transmission curves are available in Appendix 7 for the filters and Appendix 8 for the grisms Table 2 4 shows the spectral range covered in MOS modes by the various grisms as obtained by the automatic pipeline when reducing the spectrophotometric standard star This spectral range is valid for slits close to the center of the field 2 3 1 Spectral range In MOS mode slits can be positioned at any position in the imaging field of view With high resolution grisms the observed spectral range changes slightly according to the position of the slit Table 2 5 shows the spectral ranges covered by the dete
71. er oras era ba ca Cada hee eae oad a Swe be 29 44 Listottemplates os ca 444844 2 4 ed ba babe ba hee eee eb ee aS 30 45 Acquisition templates o dou da eat es he a ee AA we 30 ds VIMOS me acg Prest soam ke e Pa a Se O UE a 30 4 5 2 VIMOS mos acguMask ou e a ee ee OR we ae 32 4 5 3 VIMOS_mos_acq Standard seres 00 ee ee ee 33 434 VIMOSifuacg Preset ck ew lds sata dad wee da wh ded wks 34 46 SCIENCE templates ak bis ania eA a a a a e 35 4 6 1 VIMOS ime obs Offset o s ev ee ee E ea 35 Ab VIMOS AOS obs OSet o o e ce ok a A aa ee ee 38 aos VIMOS obs Oet o e ee meo en cal BE ee e ds owe Be a R A 39 do Calibration Templates ups eo Ek eal we e ee we ee a 40 Hid VIMOS ime cal PROM co oad e band tah ea ee da eG aw eee oes 40 4 7 2 VIMOS imp cal Astrom o es bee ea ee ee ea es 40 4 7 3 VIMOS mos_cal_NightCalib ee 41 4 7 4 VIMOS_m0Os_cal_ Standard 0 0 20 22 eee ee ee ee 41 4 75 VIMOS Ani cal Specphot assa ce a Oe SS SAD we S 42 4 7 6 VIMOS mca NighiCelibs oo be asp Ba aed AA ee 42 ALT VIMOS caL TWFA assess ga bad ea be dag ea ded a tae 43 5 Guidecam Tutorial 45 dA Getting Started with Quidecam oe kok e ace Sh ee OR we eo 45 34 Themen Guidecanm GUI co a Ge eee Pe ae E ae ae 45 Sa The USNOatESO pa el s lt c4 a cae sa tada dal wa a dean eae dela 46 54 Selecting the Guide Star o soo ea oa ee we Le a ee ee ea EA ees 47 3 3 Generating Finding Charts ss cas rain PA LEA ee ee ea 48 SG
72. f exposures taken at each telescope position is determined by the next parameter Number of exposures per telescope offset The pattern of offset is defined in the List of offsets arcsec along the slit and List of offsets arcsec perpendicular to the slit parameters Number of exposures per telescope offset This parameter defines how many expo sures are taken at each offset position List of offsets arcsec along the slitandList of offsets arcsec perpendicular to the slit Offsets are defined relative to the previous position Offsets are defined in DETECTOR coordinates along or perpendicular to the slits Usually only offsets along the slits need to be defined If the first image is to be taken at the preset coordinates the first set of offset should be 0 0 If there are less offset values than the required number of offset position the template will return at the beginning of the list of offsets and apply them again For example if 3 telescope offsets are defined Number of Telescope Offsets together with the following series of offsets apparent movement of the target on the detector List of offsets arcsec along the slit 1 2 0 List of offsets arcsec perpendicular to the slit the offsets applied to the telescope will be Offsets arcsec along the slit Offsets arcsec perpendicular to the slit or o oo i e the first exposure is taken at 1
73. f view of the IFU The 2 available samplings are 0 67 arcsec fiber and 0 33 arcsec fiber To produce a valid OB the magnification should be the same in every template of the OB Observations requiring different samplings on the same field should resort to several OBs IFU Shutter This parameter is only meaningful when using the LR grisms In LR spectroscopy there are 4 rows of fibers along the dispersion direction whereas in MR and HR modes only one slit of fibers is used hence the variation of field of view between LR and MR and HR modes In case the object of interest is of limited size in LR mode and if only the central 1 4 x 1 4 of the field of view is needed it is possible with the FU Shutter option to mask the outer part of the IFU always masked in MR and HR modes This allows to avoid second order overlap due to sky and or background objects between the 4 adjacent slits along the dispersion direction True means that the shutter is in place and masks the external part of the IFU False the default value means that the mask is not in place and the full IFU field of view is available To produce a valid OB the mask shutter option should be the same in every template of the OB This parameter is ignored when MR or HR grisms are used Rotator on Sky This parameter defines the orientation of the instrument on sky The IFU has a square geometry with the sides oriented N S and E W With a rotator angle of zero the orientation of the
74. file ID 073 A 0602C 3 18 2004 05 12T15 50 59 001 NAME wfil6_vm_LR_Red_M1Q1 adp DESC ADP Aperture Definition File in Pixel 1 FILE KEEP T TE OBS 2004 04 20T06 57 05 802 1 GS1 ALPHA 191457 06000 TE GS1 DELTA 460255 35599 TE GS1 PPOS NEG AD TE HAHAHAHA d ta 1 TEL A lle ll 4 E POSANG 90 TARG ALPHA 191427 80880 TARG DELTA 460426 61600 TARG EQUINOX 2000 TARG NAME DF GRISM NAME LR_Red F GRISM SPECTLEN 640 F SKYREG 1 8 EF NO 1 U iw LIT NO 46 HH H 222222222 2 H ANNNNNNNNN EH A A A R ARC NO O S S S S S HU NO 4 HU1 POSL 0 HU1 POSH 769 HU2 POSL 769 VLT MAN ESO 14610 3509 VIMOS User Manual VLT MAN ESO 14610 3509 INS SHU2 POSH 1549 INS SHU3 POSL 1549 INS SHU3 POSH 2249 INS SHU4 POSL 2249 INS SHU4 POSH 2440 PRO CCD MASK DAYTIM 2004 03 25T19 21 18 334 PRO CCD MASK TEMP 14 490387 PRO CCD MASK XO 131 872451572 PRO CCD MASK XX 0 11921553 PRO CCD MASK XY 0 00010888833 PRO CCD MASK X_0_0 0 18869123 PRO CCD MASK X_0_1 0 00054856849 PRO CCD MASK X_0_2 4 812277e 07 PRO CCD MASK X_0_3 1 3219545e 10 PRO CCD MASK X_1_0
75. finition in Pixels ADU Analogue to Digital Unite AT Acquisition Template BOB Broker of Observation Blocks CCD Charge Coupled Device DEC Declination ESO European Southern Observatory ETC Exposure Time Calculator FEU Filter Exchange Unit FIERA Fast Imager Electronic Readout Assembly FOMPU Folding Mirror Positioning Unit FPAL Focal Plane Adaptation Lens FWHM Full Width Half Maximum GEU Grism Exchange Unit GUI Grafical User Interface HR High Resolution IFU Integral Field Unit IMG Imaging Mode MEU Mask Exchange Unit MOS Multi Object Spectroscopy Mode OB Observation Block OS Order Sorting PSF Point Spread Function P2PP Phase 2 Proposal Preparation RA Right Ascension RMS Root Mean Square RON Read Out Noise TIO Telescope Instrument Operator TSF Template Signature File VIMOS Visible Multi Object Spectrograph VMMPS Vimos Mask Manifacturing Preparation Software VLT Very Large Telescope A Angstrom em Electron cm Centimeter 109 110 kpx min nm px VIMOS User Manual VLT MAN ESO 14610 3509 Hour KiloPixel Minute Millimeter Nanometer Pixel Second Micrometer
76. formation about the Guidecam software tool which was in the past present in the Vimos Guidecam User Manual VLI MAN ESO 14610 3512 by S Brillant 5 1 Getting started with Guidecam Using Guidecam is fairly simple 5 2 Start Guidecam by issuing the command guidecamLite after installation This opens up a skycat GUI with a specific Guide P robe pull down menu Figure 5 1 shows the main Guidecam panel Select the Settings option of the Guide P robe menu This opens up the Guide Probe Settings panel which is represented in Figure 5 2 Enter the coordinates of the target in the Telescope section of the panel Note that the coordinates have to be in J2000 and the format should be as indicated The default value of 90 degrees for the rotation angle on sky should not be modified unless a waiver is requested When pressing the Apply button Guidecam will download from the ESO archive the DSS image of the field and open a panel USNO at ESO displaying the USNO star catalog of the field This panel is represented figure 5 3 Allow for a few seconds to a few tens of seconds for the image to be downloaded At this point on it is possible to position the Guide Probe on the available catalog stars and to evaluate if vignetting occurs The main Guidecam GUI The Guidecam GUI figure 5 1 displays the image of the field the projected shadow of the Telescope Guide Probe yellow onto the telescope focal plane the VIMOS field of view
77. ft to their default values 4 5 4 VIMOS ifu acg Preset This template is for the acquisition of a field to be observed with the Integral Field Unit Unlike the MOS acquisition template the IFU acquisition template requires to define the filter grism combination that will be used in the following observation template This is to optimize the setup of the instrument at acquisition time The coordinates of the field at the center of the IFU need to be entered in the Target Package at the bottom left of the main P2PP window The parameters for this template are Filter This should be the same filter as the one used in the first observation template following this acquisition template In order to produce a valid OB the filter in the first observation template following this acquisition template should be the same The available filters are U B V R I z OS blue OS red GG435 GG475 and no filter Only standard filter grism combinations are allowed as indicated in Table 2 3 Other combina tions should be requested with a waiver Grism This is the grism that is used in the first observation template following this acquisition tem plate In order to produce a valid OB the grism in the first observation template following this acquisition template should be the same The available grisms are LR blue LR red MR HR blue HR orange HR red IFU Magnification This parameter defines the sampling and correspondingly the field o
78. g about your catalog Read through Step O again it is worth it we believe that it will actually save you time OK enough warnings if you went carefully through Step 0 you are ready to start VMMPS To do so type gt vmmps amp and you should see the following window pop up if you are a regular skycat RTD user this will look very familiar to you but notice the new plug in in the top bar VIMOS MPS or VMMPS for people who like acronyms of acronyms Skycat version 2 6 5 1 File View Graphics Go Data Servers VIMOS MPS Cross correlate Contributed and VIMOS Pre image catalogs Assign slits from a VIMOS catalog produce ADP Verify ADP File What to do next depends on the type of catalog you have prepared You have your own pre VIMOS catalog the contributed catalog case e proceed with Step 2 The VMMPS task of defining slits only accepts VIMOS catalogs and you need to produce one Do not panic VMMPS has a built in task to help you doing so using your contributed catalog together with a VIMOS pre image catalog anda VIMOS pre image What you have is a list of RA and DEC of your objects a contributed catalog and the VIMOS pre image freshly out of the ESO pipeline Make sure that the relative astrometry in your catalog is very good and that your list actually also contains on the same astrometric system a good number of objects that appear on the VIMOS pre image e g a list of only z 6
79. ge this might have happened Try then to go back to smaller values the Sigma clipping for residuals the task will find a number of objects in common between VIMOS pre image and contributed catalog It will compute the position difference in the two catalogs and some objects e g mismatches will show high values Define with this parameter when such an object will be rejected from the final fit 62 VIMOS User Manual VLT MAN ESO 14610 3509 e the Number of iterations the task will compute a first transformation for the objects in the contributed catalog applied it and if the number of iterations is gt 1 restart the cross correlation to compute a new transformation Depending on the number of out layers distortions in the field the final transformation might significantly improve with a few iterations If you see no clear improvement in RMS between two successive passes you probably reached the necessary number of iterations Once you have set the parameters click Run Cross to run the cross correlation You will get the log output of the task display in the lower part of the window The log tells you how many objects were found in your VIMOS pre image nref and contributed ncross catalog respectively Do not forget that you can set a column CROSS in your contributed catalog and only the objects with CROSS 1 will be used for the matching and counted in ncross E g you can safely put any faint high z galaxy to CROSS 0 in the co
80. grisms MR The vertical lines mark the desired blaze and the central wavelengths The spectral range refers to the slit in the center of the field The cutoff wave length is in most cases given by the order separation filters the red CCD limit or the limit of the VIMOS optics in the blue 100 VIMOS User Manual VLT MAN ESO 14610 3509 Efficiency Z 100 3 7 7 oy Efficiency Z Figure A3 Efficiency curve desired blaze and the central cutoff wavelength is in most VIMOS optics in the blue 100 je pr HIGHBLU units Desired Blaze cenirel 4 Win Spec Peak Bf 7 ge 0 6 2 8 1 1 2 AMHURA nita 80 mel Desired Blaze Nin Spec Peak UM 40 20 03 0 0 8 1 da W misrans of the high resolution grisms HR blue HR orange The vertical lines mark the wavelengths The spectral range refers to the slit in the center of the field The cases given by the order separation filters the red CCD limit or the limit of the VIMOS User Manual VLT MAN ESO 14610 3509 101 VIMOS Efficiency sao 850 900 960 1000 750 Wavelenght nm Figure A4 Efficiency curve of the high resolution grisms HR red VPHG The spectral range and efficiency refers to the slit in the center of the field The cutoff wavelength is in most cases given by the order separation filters the red CCD limit or the limit of the VIMOS optics in the blue 102 VIMOS User
81. he default option for which the guide star will be searched through a catalog and will be selected at the telescope by the Telescope Operator If this option is selected the subsequent fields Guide Star RA DEC will be ignored SETUPFILE If this option is selected the guide star that will be used is the one for which the coordinates are defined in the Guide Star RA DEC fields A dedicated tool Guidecam is delivered by ESO to help the users to determine the best possible guide star This option is mandatory for service mode imaging and pre imaging OBs Guide Star RA and Guide Star DEC Coordinates of the guide star when the SETUPFILE option of the Get Guide Star From field is selected Guide Star PPOS Position of the Guide Probe when the SETUPFILE option of the Get Guide Star From field is selected Optional additional velocity moving targets in alpha and delta Additional Velocity RA and Additional Velocity DEC This velocity should be expressed in arcsec sec These parame ters are mostly intended for imaging or possibly IFU programmes of moving targets If no additional velocity is needed these parameters should be left to their default values 0 32 VIMOS User Manual VLT MAN ESO 14610 3509 K gt UbsBlock No Name VIMO AYU ALL THOE al nabs OL sal IMOZ any obs Ofisst ditlonc Ye ac tu A aditlonz ve 27 w DEC ADF Net fern useri ma MI adp ADE lle z SDF Flle ALE ile 4 fernaz use o vm
82. he defined number of offset positions the template will return at the beginning of the list of offsets and apply them again IMPORTANT We stress that in contrast with other ESO instruments the offsets defined by the user in P2PP refer to the apparent movement of the target on the detector independently of the choice of Offset coordinates SKY or DETECTOR and not to the offsets applied to the telecope For example if 5 telescopes offsets are defined number of telescope offsets together with the follow ing series of offsets apparent movement of the target on the detector RA or X O 10 5 DECorY 2 7 the offsets applied to the telescope will be RA or X 0 10 5 0 10 DEC or Y 2 7 2 7 2 If SKY option for coordinates is selected then after the preset the first offset will be applied to place the target 2 arcsec North with respect to its previous position on the detector by moving the telescope 2 arcsec to the South 0 offset in RA At this position the first exposure will be taken After that the target will be moved further 10 arcsec West and 7 arcsec North with respect to the position of the previous exposure etc until the number of exposures is reached If DETECTOR option for coordinates is selected then the directions of the offsets on sky depends on the actual rotator angle If we assume that the orientation is such that the positive x axis points to the East and positive y axis points t
83. he rotator angle i e 90 3 3 3 IMG mode calibration plan Observations of IMG photometric standard stars during the same night as science observations are guarranteed for programs that requires photometric conditions and performed on a best efford basis during all clear nights Table 3 1 indicates the nature frequency and accuracy of VIMOS calibrations expected to be taken as part of the calibration plan Only calibration frames required for the reduction of science data are reported More calibrations will be taken by the operation staff for the purpose of maintaining and monitoring the instrument configuration and performance e g mask to CCD transformations etc These calibrations are not reported here Calibration monitoring including photometric zero points can be found on the pages of the Quality Control group http www eso org observing dfo quality VIMOS User Manual VLT MAN ESO 14610 3509 23 3 3 4 IMG mode pipeline See http www eso org qc pipeline status html for the information concerning the latest status of the ESO pipeline 3 3 5 IMG mode Exposure Time Calculator The approximate limiting magnitudes in direct imaging mode can be obtained from the exposure time calcu lator available on the ESO WEB pages http www eso org observing etc 3 4 Multi Object Spectroscopy MOS 3 4 1 Pre imaging Pre imaging is mandatory for all MOS observations Pre imaging is carried out in service mode see Sect 3 3 1
84. icient knowledge of the VIMOS Mask Preparation Software VMMPS Sect 3 4 3 prior to their visit at Paranal and to allow mask manufacturing ahead of time Limited additional support is guaranteed for mask preparation on the mountain up to 3 masks per night to be prepared at least 48 hrs in advance The instrument has a capacity of 15 masks per quadrant loaded simultaneously one slot is normally occupied by a mask dedicated to observations of spectrophotometric standard stars However some restrictions may apply for technical reasons in the number of masks which can be hosted simultaneously into the cabinets Until P77 only 8 masks can be simultaneously accommodated in the instrument cabinet 1 of which is the mandatory spectroscopic mask and the same is currently foreseen for P78 Please refer to the Call for Proposals and to the instrument WEB pages for the updated status of the instrument situation Note that masks cannot be exchanged at night 3 4 6 MOS mode grism filter setup In MOS mode only one filter grism combination per OB is permitted the only filter exchange allowed is the one between acquisition and science template Users who want to observe the same targets with different filter grism combinations are requested to submit separate OBs for different filter grism combinations and to consider the respective overheads 3 4 7 MOS mode attached night time calibrations To correct for instrument flexures the use of attached nightt
85. ide stars e Selection of a Guide Star for VIMOS observations is mandatory for MOS and IMG mode to assess and control the amount and position of vignetting that may be introduced by the Guide Probe When the guide star is selected the coordinate should be properly entered in the acquisition template together with the position of the guide probe and the guide star option have to be selected properly see 4 4 If this is not done properly your OB will not pas validation and will not be scheduled for observation See Phase 2 Web pages for detailed information VIMOS User Manual VLT MAN ESO 14610 3509 49 In case of observation involving offsets it is the responsibility of the user to check with guidecam that the chosen guide star does not produce unacceptable vignetting in any of the frame produced by the execution of the OB ESO will consider as executed within specification an OB producing vignetted frames implicitly assuming that the vignetting was already verified by the user If no guide star is provided by the user i e the option CATALOGUE of the Get Guide Star From P2PP parameter of the VIMOS ifu acq Preset template is selected the guide star will be selected by the Telescope Operator at execution time If the user provides a guide star by selecting the option SETUPFILE of the Get Guide Star From P2PP parameter of the VIMOS img_acq_Preset template efforts will be made to use this guide star for imaging pre imaging and for the s
86. ight format Assuming that you are in case 1 you need to prepare the two catalogs described in the this and the next section The contributed catalog contains all the objects that you wish to observe plus or including enough bright objects that can serve for the cross correlation with the VIMOS pre image catalog and as reference stars for aligning the mask on the sky All objects shall have very good 0 1 relative astrometric coordinates RA DEC on a single astrometric system Further all objects should have good 2 absolute astrometry The mandatory columns in the contributed catalog are in upper case and in the following order e ID defining an identifier which must be unique and integer number e RA the right ascension of the object e DEC the declination of the object RA and DEC entries are allowed in 2 formats decimal degrees hh mm ss s including semi colons The optional columns whose names are reserved are CROSS is for each object either 1 if that object shall be used for the cross correlations or O if it shall not e g if it is too faint too elongated FLAG shall be one of upper or lower case C compulsory R reference F forbidden S select able no blank entry is supported any other flag will be replaced by S select able A_ARCSEC the semi major axis in arcsec e B_ARCSEC the semi minor axis in arcsec PA the position angle E of N in degrees The latter three will be
87. ime Dark current Screen Flats 3 Daily Day time IFU Flat with Monitoring HR Orange Screen Arc 1 Daily Day time IFU Arc with Monitoring HR Orange Screen Flats Ito 3 Attached to all IFU Flat 5 science OBs Screen Arcs 1 Attached to all Dispersion coeff 0 3 pix science OBs Specphot 4 See text Night time Response 10 All grism filter Standard Star quadrants function setups used 1 Internal accuracy not considering instrument flexures see Sect 2 7 2 With grism HR blue 3 screen flats are always mandatory IMPORTANT NOTE The execution time for all attached night time calibrations screen flats and arcs is subtracted from the total allocated time 3 5 5 IFU mode calibration plan Observations of spectro photometric standard stars with the same setting used for science observations are nor mally performed within a few nights from the science observations Table 3 3 indicates the nature frequency and accuracy of VIMOS calibrations expected to be taken as part of the calibration plan Only calibration frames required for the reduction of science data are reported More calibrations will be taken by the oper ation staff for the purpose of maintaining and monitoring the instrument configuration and performance e g mask to CCD transformations etc These calibrations are not reported here Calibration monitoring data can be found on the pages of the Quality Control group http www eso org observing dfo quality
88. ime arcs see Sect 3 4 8 is MANDATORY for all MOS OBs using LR blue and HR blue grisms and strongly recommended for all setups Users may also attach screen flats The execution time for these nighttime calibrations is always subtracted from the total allocated time 3 4 8 MOS mode calibration plan Observations of spectro photometric standard stars with the same setting used for science observations are normally performed within a few nights from the science observations Table 3 2 indicates the nature frequency and accuracy of VIMOS calibrations expected to be taken as part of the calibration plan Only calibration frames required for the reduction of science data are reported More calibrations will be taken by the operation staff for the purpose of maintaining and monitoring the instrument configuration and performance e g mask to CCD transformations etc These calibrations are not reported here Calibration monitoring data can be found on the pages of the Quality Control group http www eso org observing dfo quality 3 4 9 MOS mode pipeline See http www eso org qc pipeline status html for the information concerning the latest status of the ESO pipeline 26 VIMOS User Manual VLT MAN ESO 14610 3509 Table 3 2 VIMOS Calibration Plan MOS Mode Calibration Number Frequency When Products Accuracy Comment Bias 5 Daily Day time Master Bias RON Darks 3 Monthly Day time Dark current Screen Flats 5 Daily Day
89. iminate the sky contribution cosmic rays the CCD fringing particularly strong in the red cosmetic defects on the detectors and to produce very accurate flat fielding for correction of pixel to pixel variations The dithering pattern depends on the mean size of the observed objects 1t should be larger than the mean size of the objects for the method to work efficiently 3 5 3 IFU mode grism filter setup In IFU mode only one filter grism combination per OB is permitted Users who want to observe the same targets with different filter grism combinations are requested to submit separate OBs for different filter grism combinations and to consider the respective overheads 3 5 4 IFU mode attached night time calibrations To better take into account the effects of instrument flexure the use of attached nighttime calibrations arcs and flats see Sect 3 5 5 is MANDATORY for all IFU OBs This template will provide 1 or 3 flat field images for HR grism 3 screen flats are mandatory for the other cases the user can choose the number as well as 1 arc taken at the same rotator position of the science target The execution time for these nighttime calibrations 1s always subtracted from the total allocated time VIMOS User Manual VLT MAN ESO 14610 3509 27 Table 3 3 VIMOS Calibration Plan IFU Mode Calibration Number Frequency When Products Accuracy Comment Bias 5 Daily Day time Master Bias RON Darks 3 Monthly Day t
90. in the catalog an allows you to examine its entries The main purpose of the catalog window is to edit interactively the column FLAG that was added by VMMPS and set to S select able for all objects if not present in your input catalog How and why to edit this column is explained in Step 5 and uses the lower part of the window Modify Flags The other purpose of this window is to allow you all operations permitted on skycat catalogs editing values for selected objects searching for objects etc We do not expect you to need these and therefore recommend to you not to use mis use or ab use of them Except maybe for an object selection explained in Step 4 but this is optional If you are satisfied with what you see move directly to Step 5 VIMOS User Manual VLT MAN ESO 14610 3509 65 6 2 5 Step 4 optional Re arranging your VIMOS catalog This step is optional You can skip it and move directly to Step 5 In case you are not fully satisfied with all objects in your catalog you have the chance to re arrange it some what To do so you must have the column s on which you want to constrain your objects in the catalog and you must have made up your mind which range you want to allow for this columns If this is fulfilled go in the catalog window to the pull down menu Options and select Set Search Columns The following window will pop up Search Columns for diska visitor VMMPS_tests fornax_c
91. ing IMG Imaging mode is used for both pre imaging runs and science imaging runs In both cases users are requested to use Guidecam for the selection of guide stars See Sect 3 0 2 concerning Guidecam and Sect 5 6 concerning the policy regarding Guide Stars 3 3 1 Pre imaging VIMOS pre imaging is mandatory prior to MOS follow up If you have old VIMOS pre imaging data please check with usd helpeso org to see whether it can be used as these data has a limited validity period Pre imaging is carried out in service mode only The following instructions for preparation of pre imaging OBs should be strictly followed Program ID Itis mandatory for Phase I to request a specific pre imaging run in the proposal form and for Phase II to prepare the pre imaging OBs by using the corresponding Program ID 22 VIMOS User Manual VLT MAN ESO 14610 3509 Table 3 1 VIMOS Calibration Plan IMG Mode Calibration Number Frequency When Products Accuracy Comment Bias 5 Daily Day time Master Bias RON Darks 3 Monthly Day time Dark current Sky Flats 5 3 7 days Twilight time Master Flat 2 U BVRIZz Photom Std 4 quadrants See text Night time Zero Point 5 U BVRI Photom Std 1 quadrant Weekly Night time Extinction coeff 10 U BVRI high airmass Astrometric fields 4 6months Night time Distortion map 1 pixel R filter Filter used The correction of the distortions is derived from R filter observa
92. is determines whether the standard star field will be positioned in one or four of the quadrants of the IFU As many exposures as defined in Number of exposures per telescope offset will be taken at each telescope position 1 or 4 4 7 6 VIMOS ifu cal NightCalib This template is to be used when screen flats or wavelength calibrations are needed during the night right after a science observation This template doesn t contain any setup definition and the data will be taken with exactly the same instrument setup as used in the previous observation template This template is to be used in a science OB after observation templates It can not be used alone in an OB after an acquisition template The exposure time parameters are automatically defined by the instrument setup The parameters of the template are e Night Flat Field T F Ifsetto T 3 screen flats will be taken e Night Arc T E If T an arc spectrum will be taken VIMOS User Manual VLT MAN ESO 14610 3509 43 4 7 7 VIMOS ifu cal TwFlat This template is used for the observation of twilight flats in IFU mode It is only offered in visitor mode It should go together with an attached arc The parameters of the template are Exposure time seconds This is the integration time in seconds per exposure Number of exposures This parameter defines how many exposures are taken Filter The available filters are U B V R I z OS blue OS red GG435 GG475
93. its to the objects E g if you knew in advance which ones would be your reference objects you could have created a column FLAG in the input catalog and set it to R for these objects S for all others Once you launch the automatic slit assignment Step 6 the task will allocate the slits in the above order of priority i e first put boxes around the reference objects then try to fit all compulsory objects then try to fit all curved slits and than finally assign normal slits as many other objects as possible the latter is described in Step 6 But first let s have a closer look at each type of special objects Reference objects Reference objects are relatively bright objects that will show up but not saturate on the acquisition image of 10 30 sec i e typically R 12 16 and that are used to center the masks When selected the reference objects gets its FLAG parameter set to R These objects are put by the software in each mask produced for that quadrant before any other object gets allocated a slit The reference objects are assigned a 4 x4 box Remember that in VIMOS the masks of the 4 quadrant are absolutely stiff with respect to each other Thus in theory it would be enough to have 1 reference object per quadrant or even only 1 quadrant with reference objects The software only checks for 1 reference object in your catalog and lets you get away with it However we recommend to allocate 3
94. ization Code described by Bottini et al PASP 117 996 2005 Given a catalog of objects SPOC maximizes the number of observable objects in a single expo sure and computes the corresponding slit positions It does so by solving a very complex 2D combinatorial problem 6 1 3 The importance of your catalog VMMPS fully relies on your catalog to contain exactly the objects that you want to observe In VMMPS you have hardly any freedom to set priorities for your preferred objects Your catalog should contain all and 51 52 VIMOS User Manual VLT MAN ESO 14610 3509 only the objects you really want to observe VMMPS will optimize the allocation of slits for you such as to maximize the number of objects observed from your catalog assuming that you have no favorites In summary VMMPS relies heavily on your catalog Thus instead of using your brain intensively while running VMMPS rather use your intellectual power and scientific judgment to create a smart input catalog Your catalog is the most important item in the process 6 1 4 The different catalogs that you can come with We distinguish between two different scenarios 1 Contributed pre image catalog case Prior to pre imaging with VIMOS you know already which objects you want to obtain spectroscopy for and have precise astrometry for them E g you were running an imaging survey with a wide field imager and have identified your candidates on a given astrometric system This cata
95. ken at each telescope position 1 or 4 At the end of the template the telescope will offset again to return to its position at the beginning of the template 4 7 3 VIMOS mos cal NightCalib This template is to be used when screen flats or wavelength calibrations are needed during the night right after a science observation This template doesn t contain any setup definition and the data will be taken with exactly the same instrument setup as used in the previous science template This template is to be used in a science OB after a science templates It can not be used alone in an OB after an acquisition template The exposure time parameters are automatically defined by the current instrument setup The parameters of the template are Night Flat Field T F If set to T 3 screen flats will be taken Night Arc T F If T an arc spectrum will be taken 4 7 4 VIMOS mos cal Standard This template is used for the observation of a standard star in mode MOS This template can only be used fol lowing the VIMOS mos acg Standard acquisition template and not using the VIMOS mos acg Mask This template can only use the specifically designed standard mask from the repository The parameters of this template are Exposure time seconds This is the integration time in seconds per exposure Filter The available filters are U B V R I z OS blue OS red GG435 GG475 Grism The available grisms are LR blue LR red MR
96. length calibration offsets may be introduced due to the flexures In order to minimize eliminate these effects night time calibrations can be taken with an adequate template see Sect 4 Attached flat and arc calibrations are mandatory for all IFU observations Attached arcs are mandatory for MOS science observations with grisms LR blue and HR blue and highly VIMOS User Manual VLT MAN ESO 14610 3509 21 tt peat Site Paranal o 2 00 arcsec Dec 20 r a P Tstort 2 hrs E E 7 o Tend 2 hrs E _ Fam 45micron PS ba 57micron 1 67micron Dec arcminutes 0 1 5 1 10 10 5 0 5 10 RA arcminutes Figure 3 1 Example of atmospheric dispersion at Paranal for a field at declination 20 observed with the LR_blue grism from 2 hrs from Meridian The blue and red trails show the evolution of the blue and red wavelengths during the exposure Atmospheric spectra start with N E orientation and move to N W through a N S orientation while crossing the Meridian The maximum amplitude of the dispersion is 2 at 2 hrs from Meridian Slits clearly have to be oriented N S as a default orientation to minimize the slit losses assuming that all MOS observations will be carried out within 2 hrs from Meridian recommended for MOS science observations with grisms MR HR red HR orange and HR red Execution time is subtracted from the total allocated time 3 3 Imag
97. log must have precise relative astrometry for all objects and for a number of reference stars It is important that the astrometry of the science objects and the reference stars are on the same system You will now obtain pre imaging with VIMOS extract from there a short list of objects detected on the VIMOS image the VIMOS pre image catalog and VMMPS will help you to bring your contributed catalog onto the VIMOS coordinate system 2 VIMOS catalog case You only know which objects or type of objects you are after but have no list with precise RA DEC for your objects E g you rely on the VIMOS pre image to determine the objects you will obtain spectroscopy for This catalog is obtained directly from the VIMOS image using your favorite analysis tools It takes coordinates in detector x y as well as any other parameter you want to convey and can be used right away by VMMPS provided that it has the right format see below We recommend Sextractor Bertin amp Arnouts 1996 A amp AS 117 393 without getting any royalties for it but because it serves well the purpose and you will recognize some similar structures parameters VIMOS User Manual VLT MAN ESO 14610 3509 53 6 2 Step by step guide 6 2 1 Step 0 most crucial Getting ready preparing your catalogs This step is done outside VMMPS But as mentioned above it is the most important one What you need e for each quadrant one VIMOS pre image processed by the ESO pipeline
98. m CCD top LR red OS red 550 950nm 550 950nm 550 950nm LR blue OS blue 360 670nm 360 670nm 360 670nm MR GG475 500 1000nm 500 1000nm 500 950nm HR blue Free 415 620nm 468 674nm 370 566nm HR red GG475 630 870nm 690 930nm 570 805nm HR orange GG435 520 760nm 577 817nm 463 703nm VIMOS User Manual VLT MAN ESO 14610 3509 13 VIMOS IFU ORIENTATION ON SKY Rotator angle PA 0 Rotator angle PA 90 AN AN 1 4 4 3 E E E ARA y IA 2 1 3 i i 2 Figure 2 5 Orientation of the VIMOS IFU field of view on sky for position angles 0 and 90 in IFU mode 2 4 1 IFU mode orientation of the field of view Figure 2 5 shows the orientation of the instrument field of view in IFU mode for the four quadrants On the detectors wavelength dispersion is along the y axis with wavelength increasing with y The increasing position angle on the sky east of north corresponds to the positive rotator angle Spatial characteristics are described in the Section below As for IMG MOS modes the pointing coordinates in the header correspond to the center of the VIMOS field of view Due to offset position of IFU with respect to the center the relevant header keywords which contain the information of the pointing of the IFU are HIERARCH ESO TEL TARG ALPHA and HIERARCH ESO TEL TARG DELTA 2 4 2 Fiber arrangement and spatial characteristics The special arrangement of fibers f
99. m is always best but wait The Maximum optimization mode is more efficient in terms of number of placed slits but favors the smallest X RADIUS objects The Normal Optimization is less efficient in terms of number of slits 10 less but does not bias against large objects If you have only point source go for Maximum If you have extended objects you might want to use the Normal optimization to avoid biases in your survey e The Grism the task needs to know the Grism for two reason First in order to define correctly the wavelength range second in order to define the multiplexity LR grism allow up to 4 slits in dispersion direction the MR grism up to 2 The selection of the grism will automatically set up the minimum and maximum wavelengths in the widgets below such that your spectra have the maximum length on the detector around the zero deviation wavelength of the grism The slit width arcsec this will define the slit width for all objects except for reference objects defined by a fixed 4 box and curved slits for which you have defined the slit width separately e Sky Region arcsec defines the minimum sky region that VMMPS will allocated on each side of your object in the slit The pipeline requires at least 1 8 arcsec More will reduce the number of position able slits but increase your sky subtraction capabilities later Low High Cut A define the wavelength range that you need i e the common length of the spectra
100. maging and for MOS programs In fact the guide star for MOS is selected at the time of pre imaging guide star coordinates and position of guide probe whether positive or negative is stored in the pre image headers and subsequently propagated by VMMPS see Sect 3 4 3 the VIMOS Mask Preparation Software into the Aperture Definition in Pixel ADP files At the time of the MOS acquisition this information is extracted from the ADP files and the same guide star as used for pre imaging will be re used for the MOS observations Only in some exceptional cases the telescope operator may have to select another guide star see Sect 5 6 Users need not select the guiding star for observations carried out in IFU mode The position and the amount of the vignetting introduced in the field of view by the guide probe can be controlled with the help of the Guidecam software that allows one to visualize the geometry of the VIMOS field of view and of the Telescope Guide Probe and allows users to select the guide star most suitable to their observation For a tutorial on the use of the Guidecam tool see Chpater 5 19 20 VIMOS User Manual VLT MAN ESO 14610 3509 3 0 3 Cumulative offsets For small telescope offsets the telescope may keep the same guide star However observations involving cumulative offsets greater than about 30 often result in significant vignetting of the guide probe or even in the loss of the guiding star For these reasons
101. manufacturing machine can cut slits of max 20 length which translate into 150 pixels and that you are allowed to add 10 50 pixels sky on each side VIMOS User Manual VLT MAN ESO 14610 3509 57 Getting your input VIMOS pre image ready Good news your VIMOS pre image processed by the ESO pipeline is ready as it is to be accepted by VMMPS Bad news if your image is not a VIMOS pre image or if the VIMOS pre image was not processed by the ESO pipeline or if you had the bad idea to modify the pre image even in the slightest detail e g you had 3 dithered pre images and combined them etc VMMPS will not work or in the worse case will seem to work but you will never see your objects through your slits Indeed your x y coordinates will be transformed into mm for the mask manufacturing using the transformation in the image header assuming that we deal with original x y system If you have translated re scaled re binned the image this transformation will not be valid anymore Just make sure that your input to VMMPS is an original untouched VIMOS pre image processed by the ESO pipeline Also make sure that this pre image is the one you used to obtain the coordinates for your VIMOS pre image catalogorVIMOS catalog If you would like to learn a little about the background of all this read further this section If you are just lazy and happy with the information so far go ahead and jump now to Step 1 Some Background One of th
102. n structure Mos Mask Figure 2 2 VIMOS Opto Mechanical layout 2 1 1 Instrument modes VIMOS offers the following modes for observations e Imaging IMG see Sect 2 2 e Multi Object Spectroscopy MOS see Sect 2 3 e Integral Field Spectroscopy IFU see Sect 2 4 IMG mode uses broadband filters U BVRIz MOS and IFU modes share the set of grisms and order sorting filters given in Table 2 3 In MOS mode a set of four laser punched masks made of INVAR is inserted in the focal plane In IFU mode fibers are arranged along pseudo slits in the so called IFU masks IFU masks may be inserted in the instrument focal plane in the same position as occupied by the INVAR masks in the MOS mode The spectral characteristics of the two spectroscopic modes are therefore similar but not identical 2 2 Imaging Direct imaging is used to produce wide field images VIMOS is the largest imager on the VLT using broad band filters This mode has two functions produce science images and produce the mandatory pre images needed to prepare masks see Sect 3 Table 2 2 summarizes the main characteristics of the imaging mode 2 2 1 IMG mode orientation of the field of view Figure 2 3 shows the orientation of the instrument field of view At 0 rotator angle the x axes of the CCDs are oriented E and the y axes are oriented N top panels Increasing rotator angle moves the compass coun terclockwise At 90 rotator angle the x axes
103. nal pages http www eso org sci observing phase2 VIMOS VMMPS html http www eso org sci observing phase2 VIMOS Guidecam html Visiting astronomers will find further instructions on the Paranal Science Operations WEB page and the Paranal Observatory home page http www eso org sci facilities paranal http www eso org sci facilities paranal sciops 1 3 Contact Information In case of specific questions related to Service Mode observations and proposal preparation please contact the ESO User Support Department 2 VIMOS User Manual VLT MAN ESO 14610 3509 usd help eso org For visitor mode observations please contact the Paranal Science Operations Team paranal eso org 1 4 Period of Validity of this Manual This manual is valid for Phase I preparation for Period 84 1 5 Version notes change track The first edition of this User Manual was delivered by the VIRMOS Consortium P I O Le F vre 1 5 1 Version 78 1 Version 78 1 contains more detailed and accurate information about the spectral range that can be observed in spectroscopic modes MOS and IFU with the various grisms Table 2 11 has been updated Hyperlinks have been added to the text The various sections of the manual have been re arranged All changes by S Bagnulo and M Rejkuba comments received by G Marconi and L Christensen 1 5 2 Version 79 0 VIMOS manual has been ported to the standard format for VLT manuals Changes by S Bagnulo 1 5 3
104. ng and known problems Here are some features that we have encountered for you We are grateful for anyone sending us more fea tures Remember that an expert is the one who has already made all mistakes himself you can save some time by using this list in case of problems We only assume that you have install the software properly Especially checked whether your command skycat points indeed to the right version that your environment variables have been set correctly the right Tcl Tk libraries are being used etc Since these have been our main sources of frustration when we debugged the software These will typically have the effect of not opening some windows not showing the plug in in skycat etc OK so let s assume that you have used your particular version of VMMPS successfully in the past but now you are in trouble with that particular 4 set of catalogs images 6 3 1 Cross correlation task e The circles surrounding the objects used and discarded during the cross correlation are not properly displayed in the image See section 6 2 3 This does not mean that the cross correlation went wrong you need to go to step 3 to visualize further the results of the transformation of your contributed catalog e You have run the cross correlation but not objects were found in common Bummer Check if your input catalogs have all the mandatory columns there is an overlap of objects between your contributed and you
105. nment 63 3 Olherproblems c aaa 4 46 6840 krer gaga 6 4 Examples of catalogs o o 6 4 1 A contributed catalog 6 4 2 A VIMOS pre image catalog 64 3 A VIMOS catalog oo ea ceceo cremas es 6 4 4 Example of an ADP file OS Usercheck listi us mega Em a hw eG 7 VIMOS Filters 8 VIMOS Grisms 9 Template Signature Files for Observation and Acquisition Al Acquisition Templates A2 Observation Templates A3 Template Signature Files for Calibrations 10 Abbreviations and Acronyms Chapter 1 Introduction 1 1 Scope The VIMOS User s Manual is intended to provide information on the following topics e Overall description of the instrument Sect 2 e Observing with VIMOS Sect 3 e Observing and calibration templates Sect 4 1 2 More Information on VIMOS All VIMOS Manuals are available on the VIMOS instrument WEB pages together with the most updated informations on the instrument http www eso org sci facilities paranal instruments vimos Information and software tools for the preparation of service and visitor mode observations with VIMOS are available at http www eso org sci observing phase2 http www eso org sci observing phase2 SMGuidelines html In particular information concerning mask preparation with VMMPS and guide star selection with Guidecam is given in the following additio
106. ntributed catalog since it is unlikely to find a match in the VIMOS pre image catalog On the display you will find marked the objects finally used for the transformation nmat ch green as well as the objects that were found to have a counter part in the first pass but were rejected later red This helps you to visually inspect whether the task did something meaningful The log tells you further for each iteration how many objects were found to match and what the RMS of the transformation in arcsec is for these objects You can readjust the parameters and run the task again and again and again until you are satisfied if you cannot reach that spiritual stage press Quit Once you are happy with the precision of the transformation we recommend a RMS of the order of 0 2 or lower click on Save Vimos Catalog and guess what it will save your contributed catalog as a VIMOS catalog The name of the output is composed of the name of your contributed catalog followed by _vm cat that is lt name of contributed catalog gt _vm cat You can now use this catalog to define slits Step 3 A brief word on the output it has a format complying with the one described in Step 0 It will contain all the objects of your contributed catalog It will still have all the columns that you defined in the contributed catalog plus two columns X IMAGE Y IMAGE giving in pixels the object coordinates in the reference system of the pre image Th
107. o Step 7 you forgot something Depending on your choice you will go back to Step 1 go have a coffee or go back to Step 7 respectively In the first two cases you will have created ADP files ready to be attached to OBs CONGRATULATIONS IMPORTANT note that an APD file edited by hand e g changing the slit width with a text editor will not be accepted by p2pp Based on the slitlets position and size a checksum parameter is calculated when you create the ADP files and verified again when the ADP file is attached to an OB If an inconsistency is found the ADP file will not be accepted by p2pp 80 VIMOS User Manual VLT MAN ESO 14610 3509 6 2 10 Loading verifying previously defined mask A simple way to come check the ADP your produced is offered in the VMMPS pull down menu 3rd item Verify ADP file By selecting this task you will be asked for an input ADP file and the corresponding pre image Similar to the slit assignment task it will display the pre image and open a catalog window this time containing only the objects allocated in that given Mask You can then as in Step 7 overlay clear the slits with the buttons Plot Slits and Clear Slits Under no circumstances edit the ADP file by hand You could in theory edit interactively the ADP file but you would then deserve what you would get namely no objects in the slit VIMOS User Manual VLT MAN ESO 14610 3509 81 6 3 Troubleshooti
108. o the North see Figure 2 3 then if the target falls at pixel x 0 y 0 after the telescope preset then the first exposure will be taken with the target at pixels x 0 y 10 offset is 2 which is approximately 10 pixels In other words the telescope was moved 10 pixels in the directions of the negative y axis of the detector Then the target will move to the pixel position x 50 and y 45 on the detector which corresponds in this case PA 0 to a movement of the telescope of 10 East and 7 South with respect to the previous position etc until the number of exposures is reached If the rotator angle is different than zero for example PA 45 and the offset defined in P2PP are RA or X DEC or Y VIMOS User Manual VLT MAN ESO 14610 3509 37 then Figure 4 4 and Figure 4 5 give the performed offsets in the case of DETECTOR and SKY coordi nates respectively e Observation Category PRE IMAGE is for a pre imaging program SCIENCE is for a regular science imaging program It is critical that users define PRE IMAGE for pre imaging programs Failure to do so will result in slow processing and delivery possibly till the end of the period of the data 1 1 x Figure 4 4 Illustration of the VIMOS img obs Offset template The black dots represent the position of a star which was originally at the center of the field In this example the DETECTOR option is selected and the star not the telescope is moved
109. of the instrument on sky This parameter should always be set to 90 for pre imaging templates unless a waiver is requested The orientation corresponding to 90 degrees is such that the slits will be oriented N S for the spectroscopic follow up In other words if the preset coordinates are RA 0 DEC_O then the first pointing of the telescope will center the field at R_1 RA 0 offsetRA_1 DEC_1 DEC_0 offsetDEC_1 where offsetRA DEC_1 are the first couple of offset keyword values and after N offsets the telescope will be pointing to RA N RA_N 1 offsetRA_N DEC_N DEC_N 1 offsetDEC_N VIMOS User Manual VLT MAN ESO 14610 3509 31 e es VIMOS gat pra magin lab irii a azuis tiun YZv0S_ fu bs Of sel sc ice viv05_ wg_rhs_Of set viv05_nes_chs_Of set Alpha ns 1 posi time eranr si Letz otse peervatizn Cxtezory Arri anal vele city 24 Addr onal elect DEL Guid Star Ra uud Scart DEL irrega 2743 Ed Figure 4 1 P2PP example of a pre imaging OB Alpha offset andDelta offset These are optional additional offsets in alpha and delta added to the coordinates of the object specified in the target panel at the bottom of the main p2pp window The coordinates at the center of the instrument i e the central point between the four quadrants are the coordinates specified in the Target Package plus the offsets here specified Get Guide Star From Two options are offered for this parameter CATALOGUE This is t
110. ontributed_ Column name x RADIUS Label for min value Min X_RADIUS Label for max value Max X RADIUS At this point you should chose the column s on which you want to select your catalog Click on the column name in the right sub panel then click on the left arrow in the central bar the selected column name s should appear in the left sub panel Ignore the lower part of that window you can use it for indicative purposes but you are not expected to fill in any values at this point Once all the columns you wish to select on are in the left sub panel click OK The pop up window will disappear and your catalog window will get updated as shown in the example below a File Edit Options Search Options o i e 03 38 16 835 ELIT Min Radius 00 Max Radius 5 45 Mn R MAG Max R_MAG 22 8 Max Objects 10000 Select Area Set From Image Search Results 87 ALPHA_VIMOS DELTA_VIMOS X_IMAGE Y_IMAGE CT COLOR R MAG XI FLAG 91300 35 37 02 82000 00137 01240 97800 35 36 19 13000 00438 01452 12800 35 40 54 51000 00506 00110 50200 35 40 54 29000 00587 00111 94300 35 39 56 86000 00732 00391 85400 35 41 15 73000 00905 00007 89000 35 35 32 46000 01087 01679 72400 35 36 37 86000 01136 01361 25300 35 36 53 53000 01405 01284 04000 35 33 23 86000 01929 02305 30100 35 33 50 36000 02003 02176 14700 35 36 05 94000 00091 01517 ma
111. or VIMOS IFU head is shown in Fig 2 6 The fibers numbering has been arranged following the scheme mask line module fiber i e 4 B 5 67 The arrangement of the fibers into the 4 pseudo slits mask one for each channel is reported in Fig 2 7 The detailed IFU table is distributed to the users together with the data release A masking shutter IFU shutter is provided in front of the input micro lens array this allows the exclusive use of the central 1 4 k of the field when IFU is used with intermediate and high spectral resolution grisms In this configuration only 1 fiber slit per quadrant mask is used for a total of 1600 fibers The templates for IFU mode offer the option to insert a shutter to limit the field to the central part also for low resolution grisms When small field can be accommodated this avoids second order contamination by the sky or background objects from the 3 pseudo slits corresponding to the outer part of the field of view Table 2 6 shows the spatial characteristics of the IFU mode 2 4 3 Spectral range Table 2 7 shows the spectral range covered in IFU modes by the various grisms as obtained by the automatic pipeline when reducing the spectrophotometric standard star With low and intermediate resolution grisms the spectral coverage is independent of the position of the IFU 14 Figure 2 6 VIMOS User Manual VLT MAN ESO 14610 3509 VIMOS field Mask 2 Mask 1 Channel 2 Channel 1 N Mask
112. ossible to Meridian within 2 hrs Although this represents a major operational constraint this is the only safe mode to ensure that slit losses are minimized in a systematic way for the blue setups provided that slits are oriented N S More information and simulations can be found on the VIMOS web Figure 3 1 shows a worst case scenario of MOS observations with LR_blue spectral coverage 370 670 nm for a field with declination 20 For details see also Cuby et al Proc SPIE 3355 p36 47 1998 For a different view on the optimal orientation see Szokoly G P A amp A 443 703 2005 3 2 Fringing and Flexures The amount of flexures reported in Sect 2 7 has a number of operational consequences e The accuracy of the slit positions determined from pre imaging depends on the rotator position This is for the time being one of the reasons why slit widths narrower than 0 6 are not allowed e Accuracy of sky subtraction flat fielding due to fringing at red wavelengths accuracy of sky subtrac tion flat fielding may be limited by flexures With dithering jittering sequences median running sky frames can be built in imaging or spectroscopy allowing accurate sky subtraction and or flat fielding of the data e In spectroscopy arcs and flats are taken during daytime and at constant rotator angle Depending on the variation in rotator angle between daytime calibrations and night time observations some flat field residuals and wave
113. ove on to Step 7 If you wish to change parameters again just do so and run Assign Slits again If you think that you screwed something fundamental up hey you really forgot reference objects then go back to Step 5 by clicking Back to Changing FLAGS e Dirty Trick with that title it will be the most read section of the cookbook but beware If you are interested in a redder or bluer spectral region than offered by default by the software you can instead of using the widget bar in Low High Cut type in numbers directly in the boxes If this results in a larger range than offered by default the software will not be able to allocate any slit However if you are say only interested in the very blue part of the spectra you could type in e g lower cut 3700 A and upper cut 4500 Sometimes the algorithm fails with an ungraceful core dump See Section 6 3 VIMOS User Manual VLT MAN ESO 14610 3509 75 The software will then place the slits in a band at the top of the detector dispersion direction is y with red at top and this will make sure that the full blue end of all spectra lands on the detector A word of caution the values you type in here will only constrain the positioning of the slits by the software but of course they will not influence the physical length of the spectrae for that you would need new blocking filters Thus in case of multiplexity in the dispersion direction handle these paramete
114. plate is VIMOS_img_acq_Preset The coordinates to define in the acquisition template are those of the astrometric field Offsets from these coordinates to position the field in one or the four quadrants of the instrument will be applied automatically by the template The parameters of the template are e Exposure time seconds This is the integration time in seconds per exposure e Filter The available filters are U B V R I z To produce a valid calibration OB the filter in the first observation template following the acquisition template should be the same as the one in the acquisition template VIMOS User Manual VLT MAN ESO 14610 3509 41 Number of exposures per telescope offset This parameter defines how many ex posures are taken at each offset position 1 or 4 1 or 4 quadrants This parameter allows to define if the astrometric field image will be taken in 1 or 4 quadrants If the 1 quadrant option is selected the astrometric field will be positioned in only one quadrant by applying an appropriate offset from the coordinates of the field defined in the target package of the acquisition template If the 4 quadrant option is selected the astrometric field will be positioned sequentially in the 4 quad rants by applying the appropriate offsets from the coordinates of the field defined in the target package of the acquisition template As many exposures as defined in Number of exposures telescopes offset will be ta
115. r and East is up y on detector thus a positive angle here is measured from north 0 to west 90 which by the way would make very limited sense Slit Width arcsec 10 PI Rotate Angle degree 15 p Image Statistics Image X 12683 Image Y 12374 08 00 11 180 b 10 44 11 29 Equinox 2000 Once you are happy with you curved slit click Save This will update the FLAG of the object to A and store the fit parameters Unselecting objects You can at any time reset a FLAG to S select able i e erase the special flag you allocated to a object To do this click on a special object then click on the button UNSEL If you look now in the catalog the FLAG has been reset to S VIMOS User Manual VLT MAN ESO 14610 3509 73 6 2 7 Step 6 The automatic slit assignment your first ADP draft Once you have at least defined a few reference objects and modified all other flags of your choice in Step 5 you can let VMMPS assign all the slit automatically the relaxing part Select in the catalog window at the very bottom Automatic Slit Assignment This will open the following pop up window with the central sub panel empty to start with mmps poc 1 LR Blue multiplex4 Here you should define several parameters 74 VIMOS User Manual VLT MAN ESO 14610 3509 e The Code Method Maximum or Normal Optimization yeah you think maximu
116. r Motion Delta TEL TARG ADDVELALPHA 15 15 Additional Velocity RA TEL TARG ADDVELDELTA 15 15 Additional Velocity DEC VIMOS_mos_cal_Standard Keyword Range Label in p2pp DET WIN1 UIT1 1 100000 Exposure time seconds INS FILT NAME UBVRIz Filter OS red OS blue GG435 GG475 INS GRIS NAME LR blue LR red MR HR_blue Grism HR orange HR red INS SLIT NAID 0 8 1 0 1 2 1 5 1 8 2 2 5 5 0 1 0 SEQ NEXPO 1 1000000 Number of exposure per telescope offset SEQ CAL FLAG 14 1 or 4 quadrants VIMOS User Manual VLT MAN ESO 14610 3509 VIMOS ifu cal Specphot HR orange HR red Keyword Range Label in p2pp DET WIN1 UIT1 1 100000 Exposure time seconds INS FILT NAME UBVRIz Filter OS red OS blue GG435 GG475 INS GRIS NAME LR blue LR red MR HR_blue Grism INS IFUE NAME 0 33 0 67 IFU magnification in arcsec fiber INS IFUS MODE FT IFU Shutter SEQ NEXPO 1 1000000 Number of exposure per telescope offset SEQ CAL FLAG 14 1 or 4 quadrants VIMOS ifu_cal_NightCalib Keyword Range Label in p2pp SEQ FLATFIELD FT Night Flat Field SEQ ARC FT Night Arc SEQ FLATFIELD NEXPO 1 1000000 No of scrrenflats 107 108 VIMOS User Manual VLT MAN ESO 14610 3509 Chapter 10 Abbreviations and Acronyms The following abbreviations and acronyms are used in this manual ACQ Acquisition ADP Aperture De
117. r VIMOS pre image catalog you have up loaded the right pre image which is used to make the link between contributed and VIMOS pre image catalog coordinates e Your final transformation gives RMS gt 1 hmmm are you sure that your contributed catalog has a good astrometry Especially that it does not suffer from any distortions 6 3 2 Automatic slit assignment e VMMPS currently does not check for the presence of reference objects see section 6 2 6 It is required that at least one reference object is defined per ADP file and your OBs will be rejected by the User Support Department if this is not the case You loaded pre image and catalog but hardly any no object appears in the catalog window or is marked in the display check in the catalog window the Max Radius It happened to us that with the columns X WORLD and Y WORLD in the catalog skycat decided to pick its own Max Radius which produced the funniest effect OK you are not in a mood of laughing right now never mind Try changing by hand the Max Radius to something really big 27007 e The classical one you pressed during step 6 the button Assign Slits but of the gazillion of objects in the catalog none was assigned a slit you might have been too ambitious in the common wavelength range Try reducing it check the flags in your catalog there are not all F for some reason aren t they 82 VIMOS User Manual VLT MAN ESO 14610 3509
118. rs with care in order to avoid contamination along the dispersion direction If you have no clue of what this is all about you should probably not try the dirty trick gt The VIMOS instrument web pages give a good overview of the wavelength range you can expect for each grism as a function of the slit position on the mask Did we mention that our web pages are great Have you read them carefully 76 VIMOS User Manual VLT MAN ESO 14610 3509 6 2 8 Step 7 optional Fine tuning last corrections This step is optional You can skip it and move directly to Step 8 The end of Step 6 triggers your old catalog window to disappear and a new one to appear as well as the display to be updated The new catalog window looks as below and is composed of as many virtual layers as you defined masks for this quadrant You can step from window to window under Modify Slits Choose Mask and use the pull down widget that also indicates on which mask you are currently working field 1Q1M 1 adp_cat 1 Search Options Object Name 2 Equinox 2000 080007778 2 S d 0 44 14 87 Min Radius 00 Max Radius 5 45 Max Objects 10000 0 33 2256 72 404 429 774 408 1355 64 1855 49 351 687 1163 35 1729 13 2156 54 E 5 275 173 10 44 54 29054 1028 DONO NO AD AO AO AD AO AO ADO Fiter Modify Slits canoso most HE Clear Slits Make Final 3 ADPs At this point your ADP has been
119. s 1 1 3 Contact Information 4 4 04 eae ee Rha a ee bee eee em E 1 1 4 Pernod of Validity of this Manual ss na e a RE RSA A a e A 2 Lo Version moles change track i s ose fae da Oe we ee ee ee Oa E A 2 SI VEO ISA oe es we a we eee ee er a wR Ee a a 2 15 2 Version 79 0 sey 6h4 Pb ea Peg a Pas dea ka ee ee he OG AA Sees ks 2 LOS VOI 0 cosmos eee ee eho bbb ede o bake eee ed 2 154 Version SO lt a BS we hea ee be dhe EG CS A Ge 2 LS Neon GAY ums a o ew aa a awe Oe Ow OE Re aa eS 2 L36 VERONESI O vosos Sos apo A E we aA Ge a eee E aed 2 lay Acknowledgments sussa age da seas aude hd aa a de Ha 3 2 Instrument Characteristics 5 LU OVSIVIEW a r ka A Bee A Go Beck Mae Bare a Hee a a 5 ZA Instrument modes i e 44 eon Sw Rad we ald BE AG a MRS 7 2 IDAS oso coe a DBS OE SE a PA oe EE ARLS OE E E ME ed 7 2 2 1 IMG mode orientation of the field of view o o oo o 7 222 Image Quality i e en ge mer E a pea Eee ee oe ee ee 10 ua a AN 10 2 3 Multi Object Spectroscopy MOS 6 04 6540 4244 He a mas a a 10 23d Spectral range coord ee bE de SE E ea E E US dE A 10 23 2 spectral resolutio o ds ce ee s be ee oa ee ee 11 233 Multiplex charactensics as cms ee ee Oe ee AS A ee 11 2 3 4 MOS mode orientation of the field of view o o 11 24 Integral Field Umit TFU 65 oa ea ea coca ba ee da RR ac we ee 11 2 4 1 IFU mode orientation of the field of view o o 00s 13 24
120. s a window that allows you to change any entry for that object typically you want to change only the values of DIMX_SLIT slit length and DIMY_SLIT slit width If in doubt use the values of the other objects in the catalog as reference Once you are done click on Enter verify that the val ues have been updated in the catalog and click on Close A good practice is then to Plot Slits and visually inspect whether your new slit has the right length i e dimension in x or whether it is overlapping touching other slits Remember to be generous with space between slits as you have to respect some physical mask stability criteria VIMOS User Manual VLT MAN ESO 14610 3509 77 We caution again from doing to many modifications at this point none should be necessary since it is much easier to screw things up here than to improve them Remember that the task already optimized the allocation If you modify anything be sure that you are still respecting all constraints including contamination issues along the dispersion direction calibration issues pipeline requirements If you have any doubts do not modify anything that mask is certainly good enough already The software will not check whether your new slits are overlapping in the spatial or spectral direction with already allocated ones The display now shows all objects in your input catalog marked with white circles and the objects for which slits were allocated
121. s do not receive sky light 2 5 Detectors The detector mosaic of VIMOS consists of four 2kx 4k EEV 44 82 CCDs thinned and back side illuminated single layer coating Table 2 9 indicates the basic characteristics of the VIMOS CCDs Figure 2 8 shows the quantum efficiency curve of one of the CCDs 16 VIMOS User Manual VLT MAN ESO 14610 3509 Table 2 8 IFU spectral coverage in the various quadrants Grism Ql Q2 Q3 Q4 LR blue OS blue 390 670nm 395 675nm 400 680nm 400 680nm LR red OS red 570 915nm 580 930nm 590 930nm 585 930nm MR GG475 485 1015nm 490 1020nm 490 1020nm 490 1015 nm HR blue free 415 620nm 415 620nm 415 620nm 415 620nm HR orange GG435 525 745nm 525 745nm 525 745nm 525 740 nm HR red GG475 635 860nm 635 865nm 635 860nm 645 875nm Table 2 9 Basic characteristics of the VIMOS CCDs Parameter Value Number of pixels 2048 x 4096 Pixel size um 15 Dark current at 120 C e px h lt 7 Deviation from Linearity Full well lt 0 5 Charge transfer efficiency gt 0 999999 3 a E SA A ER RA A E LER A DAS iiidid iki ter Tr 300 350 400 450 500 s20 600 650 700 760 so 250 900 980 1000 4050 1100 Wavalength nn Figure 2 8 QE curve of one VIMOS CCD 2 5 1 Detector read out modes The CCDs have two read out ports but only one is used This increases the read out time but as a benefit the gain
122. s_testfamaxQ1 fits Output VIMOS cat home mkisslerVIMOS VMMPS Old vmmps_testfornax_contrib i Matching tolerance arcsec 2000 65532 4 32 6188 19 TS ee e A 655324 w js o Sigma clipping for residuals Bl Number of iterations rms 1 166 arcsec The vmmps cross window summarizes your input top part and awaits your tuning of the cross correlation parameters At the beginning the bottom part is empty The cross correlation parameters are the matching tolerance in arcsec what is the maximum difference in position that you want to allow between VIMOS pre image and contributed catalog to still consider two objects to be the same If your astrometry in the contributed catalog is perfect pick a small value you are sure that if VIMOS pre image and contributed catalog position do not agree by say 2 the objects cannot be the same Remember however that the VIMOS pre image suffers from optical distortion differential atmospheric refraction etc i e the position in the VIMOS pre image catalog will not be perfect If you suspect the absolute astrometry of your contributed catalog to have a systematic offset use a larger value e g 5 This should take care of it and allow to find matching stars The danger are mis identifications if the RMS of the final transformation is lar
123. sec CORRECT LABEL parameters e Number of exposures per telescope offset This parameter defines how many expo sures are taken for each offset position e List of offsets arcsec List of offsets between exposures Offsets are defined relative to the previous position The offsets are defined in RA DEC If the first image is to be taken at the preset coordinates the first set of offsets should be 0 0 If there are less offset values than the defined number of offset positions the template will return at the beginning of the list of offsets and apply them again For example if 5 telescope offsets are defined Number of Telescope Offsets together with the following series of offsets apparent movement of the target on the detector in RA DEC RA 0 10 5 DEC 0 5 10 40 VIMOS User Manual VLT MAN ESO 14610 3509 the offsets applied to the telescope will be see also Sect 4 6 1 RA 0 10 5 0 10 DEC 0 5 10 0 5 4 7 Calibration Templates 4 7 1 VIMOS_img_cal_Photom This template is for acquisition of photometric data zero points in Imaging mode The acquisition template to use with this template is VIMOS img acq Preset The coordinates to define in the acquisition template are those of the standard star field Offsets from these coordinates to position the star field in one or the four quadrants of the instrument will be applied automatically by the template The parameters of
124. ta ga assa paga o pipas 600 800 1000 600 800 1000 Wi nm Wi nm 1 1 1 1 1 800 500 600 700 800 Wavelength nm Figure A4 GG435 GG475 transmission curves 95 96 VIMOS User Manual VLT MAN ESO 14610 3509 Chapter 8 VIMOS Grisms This appendix contains the efficiency curves of all standard grisms available for VIMOS and the approximate wavelength range for a slit which is located in the field centre 97 98 VIMOS User Manual VLT MAN ESO 14610 3509 100 T T T T T T T T T Dusired Blave LORRED wuilu L Central W AD Min Sper Peak Fff 60 2 EN 2 F wm F 20 FP th 1 l 1 f 1 1 1 a 1 1 na 1 if WL microns ico LOWBLU units Deniro Rare su Centro W Min Speu Pesak Elf SE ty E Kd E j Ris w do sb o P 1 pal A Los ss 0 4 QE 0 8 1 W microre Figure Al Efficiency curve of the low resolution grisms LR red LR blue The vertical lines mark the desired blaze and the central wavelengths The spectral range refers to the slit in the center of the field The cutoff wavelength is in most cases given by the order separation filters the red CCD limit or the limit of the VIMOS optics in the blue VIMOS User Manual VLT MAN ESO 14610 3509 Efficiency vo Bo Eu pq e e e e TT Desirec Maze INES anita central Wavelength NL mierons 99 Figure A2 Efficiency curve of the medium resolution
125. this template are e Exposure time seconds This is the integration time in seconds per exposure e Filter The available filters are U B V R I z To produce a valid calibration OB the filter in the first observation template following the acquisition template should be the same as the one in the acquisition template e Number of exposures per telescope offset This parameter defines how many ex posures are taken at each offset position 1 or 4 e 1 or 4 quadrants This parameter allows to define if the standard star image will be taken in 1 or 4 quadrants If the 1 quadrant option is selected the standard star field will be positioned in only one quadrant by applying an appropriate offset from the coordinates of the star field defined in the target package of the acquisition template If the 4 quadrant option is selected the standard star field will be positioned sequentially in the 4 quadrants by applying the appropriate offsets from the coordinates of the star field defined in the target package of the acquisition template As many exposures as defined in Number of exposures per telescope offset will be taken at each telescope position 1 or 4 At the end of the template the telescope will offset again to return to its position at the beginning of the template 4 7 2 VIMOS img cal Astrom This template is for acquisition of astrometric data in Imaging mode The acquisition template to use with this tem
126. tion provided in this part applies to both service and visitor modes 4 2 Template names VIMOS templates are divided in groups according to the instrument mode and to the observations to be performed This is reflected in the name of the various templates The template naming scheme is the following VIMOS_ lt mode gt _ lt type gt _ lt description gt tsf where mode is the mode of the instrument either img mos ifu type is the type of the template either acq obs or cal description is a string identifying the purpose of the template Offset for an observation Preset for a preset NightCal for attached night calibrations etc 4 3 Things to know Reminder e See Sect 2 2 1 for a description of the orientation on sky of VIMOS e The default orientation on sky for MOS and pre imaging templates is 90 see Sect 3 1 Any departure from this value should be requested with a waiver e Offset convention The templates make extensive use of telescope offsets which are entered manually as lists The convention is that offsets are relative to the previous position and that the first exposure is executed after the first offset is applied Thus if the first exposure is desired at the position of the preset 29 30 VIMOS User Manual VLT MAN ESO 14610 3509 then the first offset should be 0 0 In some templates the offsets can be defined in detector coordinates e g X Y or in RA DEC All offsets are to be defined in
127. tional velocity moving targets in alpha and delta Additional Velocity RA and Additional Velocity DEC This velocity should be expressed in arcsec sec These parameters are mostly intended for imaging and possibly IFU programmes of moving targets and a priori unlikely to be of much use in MOS mode If no additional velocity is needed these parameters should be left to their default values VIMOS User Manual VLT MAN ESO 14610 3509 33 e olix Eu lie z a PAFHORSTART PALA YEL para e PAFID 6D 4 90314 2 1 2002 14 18T1 7 45 1 0D1 1 PARNAME Ternaz_ms2r1_vmQ Ima j PATDEST TADO Aperture Detinitien File in Mud ado PAR 2 r 2 _veerL_vn0lIL alo PACCHICAKAME Temps 2407 Eocrex verl m azz PAF CRTE DAYTIM 2002 11 16T17 45 1 6 001 E PARELH MAME focr y veeri vnom aiz PAFACHG DAYTIM O Pare vsemi omi am PAFCHCENAME focrzy veer vno aiz ATACA Let PR Pr PAFCHCKAHECKSUM Pq ent es PAFHOREMD farra veers vn aiz INSTRUME VIMO S Fares vremi mins s OCS CON QUAD 1 Captor 30 4 ES 722 Jian tre VQ 4 INS ADE TYPE MOST Faero eec mE air INS ADENFRSION 4 07 ocre trend on som Pepita PIXEL E INS ADEID TOMAS USERT VIM Ap Peray veerd vnin aiz INS ADE COMMENT R p INEM SK Llb 1 DELA ILLDINNAME ANS NOOLSANS USLIVAD TPLFILE KEEP T DATE 98S 2002 11 1 1T05 23 29 637 TT G54 APHASIA MAM W TELAS DELTA 954244 87599 ADAROS ANG UT TTL TARG AI PHA PSS AA TFI TARG DEITA 354212 DARNT TEL T
128. tions only To minimize the slit losses due the distortion of the instrument the use of the R filter for pre imaging is mandatory Pre imaging with filters other than R may be requested with a waiver Observation Category PRE IMAGE Itis mandatory to set the Observation Category to PRE IMAGE in the observation template VIMOS img obs Offset see Sect 4 Failure to do so will result in delays to process and deliver the pre imaging data and may result in MOS observations not being carried out Rotator on sky The rotator on sky otherwise called position angle on sky cannot be freely selected by the user This is in order to minimize the slit losses due to atmospheric dispersion Sect 3 1 The default value assigned to this parameter in P2PP should therefore not be modified The default value is 90 and corresponds to an orientation of the field with E to the top N to the left see Fig 2 3 In special cases it may be possible to deviate from these rules if there is a valid scientific reason in that case a waiver must be specifically requested to ESO before you submit your Phase II information 3 3 2 Science imaging Observation Category SCIENCE It is mandatory to set the Observation Category to SCIENCE in the observation template VIMOS img obs Offset see Sect 4 otherwise data will be treated as pre imaging and will not be processed as regular imaging data Rotator on sky Users are encouraged but not forced to use the default value of t
129. tly the number of user masks that can be mounted at the instrument cabinet is 8 as 2 slots are used by calibration masks Please refer to the VIMOS web pages for updates summarized in Table 2 1 A schematic optical and opto mechanical layout is shown in Figs 2 1 and 2 2 The focal plane is divided in 4 identical channels and is equipped with the mask exchange units MEU which host up to 8 pre punched masks for MOS spectroscopy per quadrant the IFU fiber head and the IFU masks The Focal Plane Adaptation Lens FPAL reduces field curvature from 2m to 4 1m partially corrects astigmatism and make the the field curvature concentric with the new exit pupil The Pupil Relay Lens PRL correct for pupil chromatism in combination with FPAL and is the first elemnt of the collimator The folding mirror section hosts the four folding mirrors and the flexure compensators The Filter Camera Section the beam section hosts optical analyzers filters and or grisms the camera and the exposure shutter in front of the CCD FEU the filter exchange units one for each channel are located below the main body of the instrument below the Filter Camera Section each unit hosts a juke box of 10 filters permanently mounted GEU the grism exchange units are located below the Filter Camera Section they host a carousel of six grisms permanently mounted VIMOS User Manual VLT MAN ESO 14610 3509 7 ee P Sop lo Mirrors eee gt DS ORE ma
130. to 4 reference objects per quadrant in a triangular pattern With some experience you will also put them out of the way of slits or slit rows e g in a triangular pattern away from the field center but avoiding the field corners and edges where optical distortions can be large These reference stars will allow you or the astronomer on duty to verify that indeed no single mask is tilted with respect to the three other ones Make sure that these reference objects are centered in their respective boxes as the acquisition software will use the position of these objects for a first estimate of the offset needed to be applied to the telescope to center the mask If you intend to observe very faint objects which will only become visible after the combination of many exposures then assign a few slits per quadrant to brighter objects which will serve as a sanity check for the VIMOS User Manual VLT MAN ESO 14610 3509 69 observer The presence of those objects in the resulting spectral frame will indicate that indeed everything went fine with the observations New reference objects It can happen that no object in your catalog is suited as reference star In that case you can add reference stars directly from the image This should not be the default mode since the centering algorithm used by skycat is a simple Gaussian fit and might not return as accurate coordinates as your favorite source detection program The whole alignment procedure on sky
131. ts For faint objects order overlap is usually not a problem only the sky will contribute significantly to the overlap with a contribution that cannot be distinguished from the first order This however constrains the positioning of the slits in the focal plane stacked slits along the dispersion direction have to be strictly parallel and of the same length to allow the second orders to overlap nicely with the first order of the adjacent slits With the low resolution grisms the use of no filter instead of the default order sorting filters OS blue and OS red will result in longer spectra and second order overlap It is strongly recommended to reduce the multiplex number of slits along the dispersion direction to avoid reduce multiple overlaps The multiplex can be reduced by increasing the distance between slits 2 3 4 MOS mode orientation of the field of view The orientation of the instrument field of view in MOS mode can be inferred from Figs 2 3 and 2 4 taking into account that not tilted slits are oriented along the x axes and that wavelength dispersion is along the y axis with wavelength increasing with y 2 4 Integral Field Unit IFU The Integral Field Unit IFU is a dedicated opto mechanical system aimed at producing spectra of a contigu ous area of up to 54 x 54 arcsec The sky image is projected onto a micro lens array with a choice of two spatial samplings magnifications 0 33 or 0 67 per resolution element fibre Each
132. ubsequent MOS observations although this cannot be entirely guaranteed Observing conditions seeing Moon etc may indeed force to select a different guide star than the one selected by the user In addition it may happen that a guide star suitable for pre imaging observations will not be usable for the spectroscopic follow up if e g the seeing has changed ESO reserves the right to charge to the time allocated to the run the time spent in identifying and setting up the alternative guide star The use of the guidecam tool is mandatory also for the preparation of the finding charts to be delivered as part of their Phase II material The finding charts should clearly indicate the guide star to be used 50 VIMOS User Manual VLT MAN ESO 14610 3509 Chapter 6 VMMPS Tutorial 6 1 The VMMPS philosophy This chapter contains the info from the VMMPS Cookbook by M Kissler Patig and G Marconi VLI MAN ESO 14610 3511 formatted to fit in this manual 6 1 1 What does VMMPS do VMMPS is a software that in the end produces a file that you must attach to any of your VIMOS multi object spectroscopy OBs That file called Aperture Definitions in Pixels ADP file contains the list of all slits positions sizes shapes that will be milled into that particular mask The file contains this information in pixels coordinates and hosts in addition the transformation that it got from the pre image header on how to transform that particular x
133. used to compute the object size in pixels along the x direction of the detector i e along the slit Any other columns whose names do not match the above ones Notice only that the names X IMAGE and Y IMAGE are forbidden in the contributed catalog they are used computed later If these are present the software will kindly reject your catalog until you removed them All columns present in the contributed input catalog will be carried over to the output catalog Some columns will be used to generate new columns in the output catalog see below Step 2 The example of a contributed catalog is given in Section 6 4 1 VIMOS User Manual VLT MAN ESO 14610 3509 55 Preparing your VIMOS pre image catalog The VIMOS pre image catalog accompanies the contributed catalog with the only purpose to transform the RA DEC coordinates into x y coordinates This automatically corrects for any distortion in the VIMOS optics and most importantly for the mask manufacturing for x y the transformation into mm ona physical mask is known we have determined that for you and stored the information in the pre image header You need in the VIMOS pre image catalog a small number e g 50 or more of objects that are also in your contributed catalog Inthe VIMOS pre image catalog you shall have the x y coor dinates of these objects obtained from exactly the same VIMOS pre image as you will input into VMMPS Note that the more good objects are in common between the
134. ve to be prepared with the VIMOS mask manufacturing preparation software VVMPS The strategy behind observing blocks and templates is to prepare the observations well in advance to minimize any interactive steps during the observations optimization and service mode compatibility The execution of the OBs will be mostly automatic and the execution will be done by telescope and instrument operators and staff astronomers Direct interaction at execution time is only required for the target acquisition and to assess the quality of the data The preparation of visitor and service mode observations requires special care and the relevant documentation should be consulted See Sect 1 for instructions on how to retrieve the corresponding information 3 0 1 Interactions with the telescope 3 0 2 Guide stars and Guidecam software tool For telescope guiding and active optics correction it is necessary to find a guide star of magnitude in the range 11 13 5 within the Nasmyth field of view The guide star is picked up by the Guide Probe which is attached to the telescope adapter Note that the adapter is independent of the telescope rotator to which the instrument is attached In IMG and MOS mode it is not always possible to find a guide star such that the Telescope Guide Probe is not vignetting the VIMOS field of view Therefore users are asked to select the guide star for their observations The choice of the guide star is mandatory for pre imaging for i
135. y values into millimeters on the mask Further that file has as well all the necessary pointing information obtained from the pre imaging Creating these ADP files is your goal As an input you need the VIMOS pre image and a catalog of objects And how to get from there to your desired output product is all explained step by step below NOTE that VMMPS handles separately each quadrant You will have to run VMMPS 4 times to produce one full set of masks to be attached to 1 OB the software helps you somewhat to do that The important point here is that you will have to prepare for VMMPS an input set catalogs s and image for each quadrant 6 1 2 This is not FIMS you have little chance for interaction Many MOS users will be familiar with FIMS the software that helps you defining masks for FORS VMMPS is very different The main reason being that VMMPS was conceived as a tool to define masks for surveys Unlike FIMS it will hardly allow you to allocate slits manually Instead it will automatically optimize the slit assignment for object in your catalog Of course you can pick some or even all objects by hand but it will cost you time and nerves and the allocation will not be optimized in terms of numbers It is long term objective of ESO to harmonize the mask preparation tools between VIMOS and FORS after a few periods of VIMOS observations of experience and of feedback from the users At the heart of vmmps is SPOC the Slit Positioning Optim

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