TCP USER MANUAL “FULL
Contents
1. Em Me de 13 S84 33 GN Y Dc Bae RES II 22 41 29 00 40 13 32 00 ECE Ea ad BY i o f amara cocntral Figure 11 Information about the selected object Field 4 shows the air mass and Field 5 the sidereal time These data will be saved in the image headers TCP user manual 15 11 2012 4 GETTING THE IMAGES 4 1 Full frame The full frame images will be saved in the subdirectories tcp for objects darks flats or bias depending on the selected image type The steps to be carried out are listed below gt Check that single shot option in area 1 Exposure is selected gt Select the exposure time by typing it directly or Single shot using the arrows Sequence Tirne s Frames D m 2 gt Select the filter in area 2 Filter pu sister made gt Check that the Full frame option is selected in area fe Full fi 7 EO 3 Transfer mode Windows gt In this area select the type of image to be taken Flat field Dark Bias or Object The images will be saved in the subdirectories flats dark bias o tcp depending on this selection gt Take the image by pressing START button in area 1 Figure 12 Full frame image sequence If the program does not respond when you try to change the filter contact the Support Astronomer Appendix ll Problem 3 After each exposure some image informati2. gt In the filter option set the first filter of the cycle e g select B number 2 for a BVI sequence gt In the exposure field set the exposure time In the sequence field set the sequence time exposure time overheads and the number of frames gt Start the sequence by pressing the START button zi Tromso CCD photometer zs ej File Camera Tools View Help De OL Be vici 2c 22 s s 4f 13 3200 373 0413 44 eA Figure 21 Setup button of the multicolour mode 16 TCP user manual 15 11 2012 uid Eilierselecton T fevr fo B fo Figure 22 Filter and exposure time selection The sequence is set by pressing in order the filter buttons green arrow The exposure time for each filter is set in the right field red mark using the arrows The sequence is indicated in the upper field Sequence Time s Frames b Ab s Filter Transfer made Figure 23 Button enabling the multicolour mode 4 5 2 Multicolour mode different exposure times for each filter This observation mode is more versatile but the procedure involves additional steps The following describes how to proceed 1 Press the button to activate the filter selection see Figure 21 2 This action opens an information box see Figure 22 Select sorted the sequence of filters to be used and the exposure time for each see Figure 22 To do this click on each of the selected f
3. manual 15 11 2012 gt To stop the sequence press ABORT button placed where the START button was before 4 5 Observing in multicolour mode The TCP offers the possibility of observation sequences using a single filter default or multicolour mode For this reason there is a button on the left side of the user interface that activates or deactivates the multicolour mode multifilter There are two different procedures to access this option as the user could want to use the same exposure time for all the filters or to assign a different exposure time for each of them In general the steps to observe in multicolour mode are gt Bias and flats are taken as explained in Section 4 2 Of course as many flats series as filters to be used must be taken The process for taking full frame images is also performed as described in Section 4 1 4 5 1 Multicolour mode common exposure time This is the simplest procedure Proceed similarly as was described in Section 4 4 but before starting the sequence the following steps must be added gt Press the button that activates the filter selection see Figure 21 gt This opens an information box see Figure 22 below Select the filter sequence to be used sorted To do this click on each selected filter green arrow NOTE In this mode SET THE EXPOSURE TIME TO ZERO FOR ALL FILTERS boxes to the right of each button gt Enable the multicolour mode see Figure 23
4. the electronic racks Turn them on again wait a few seconds and then see if the red light flashes o If the light still does not blink check the connections serie cable from the electronics to the yellow box labelled as int and from this box to the gps labelled as gps 22 D TCP user manual 15 11 2012 a ee APPENDIX Ill Pixel size and detector orientation From an equatorial field with more than 150 stars the astrometry of the field has been measured This gives the scale of the detector and its orientation on the sky Scale 0 537 0 002 arcsec pix Orientation North axis 509 85 0 03 0 up 90 right East axis 140 85 0 03 0 up 90 right The figure below shows graphically the orientation in which the images are saved left as you would see in DS9 right as you would see in the TCP display In the graphical interface display the images are rotated 90 degrees clockwise and flipped i e where E is the N and N where the E To see the images in the standard orientation in DS9 select Invert Y in the Zoom menu and then rotate the image 45 in the pan zoom rotate parameters option x Figure 26 Image orientation a DS9 b TCP display 29
5. time in the DATE OBS field By looking to the seconds spent from an image to the next one from w00000 fits to w00003 fits in this case we find our Sequence Time 4 Set the computed value for the Sequence Time in the corresponding field and set the number of frames to 9999 or to 0 see Figure 23 5 Press the START button to start taking images 18 KROES TCP user manual 15 11 2012 Figure 24 Parameter selection for multicolour mode observations different exposure times 19 TCP user manual 15 11 2012 APPENDIX I Additional notes e Field of View TCP s field of view at IAC80 is 9 2 x 9 2 arc minutes e Detector Linearity The most energetic pixels should not exceed 30 000 counts If the object is a very bright star and photometric accuracy is required the procedure is to defocus the telescope until the maximum number of counts is into the linear regime and then increase the size of the windows e Detector Temperature The detector must be cooled by the peltier about 35 degrees below room temperature The temperature appears at the bottom information line of the graphical interface see Figure 25 If the detector temperature is considerably higher maybe the peltier is not working properly In this case contact the support astronomer ES 8 ioe 0 35 31 1 33 26 HH C Dae 20 Done 384 465 2336 p100 1 26 4 j Figure 25 Detector Temperature Info e Darks Normal f
6. TCP USER MANUAL FULL FRAME MODE TROMS CCD PHOTOMETER Last modified 09 10 2012 This version Jorge Garcia November 2012 Send comments and suggestions to Jorge Garc a jogarcia AT iac es Or to The IAC Support Astronomers Group ttnn a AT iac es TCP user manual 15 11 2012 INDEX 1 INTRODUCTION TE 3 PA STARTING A SESSION Renee enorme nO nr ene a ere ENEE 4 3 INFORMATION ABOUT THE OBJECT ccceeeccscceccessessssssssssssnssssssnsssnnees 8 4 GETTING THE IMAGES 1 0 0 cccccccccccccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 10 he Mae Me WIL AE AIAN ist ste ea apie seu a nines aur sacra oe esate casinos UM 10 d LE Ideal Uc 0 2 Hoe ne eae EIUS 11 4 1 2 Example 1 flat field in B filter 5 seconds exposure time 12 215 gt lt 0 0 0 2 bt ee E EE E eer IM UU EDU E UE 13 4 1 4 Example 3 Astronomical objects cccccccccccccccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 13 4 2 Taking BIAS FLATS and DARKS sisssscachintiacetesrveacvensscestansncaphentiasedeaaseasbessseevess 14 oa 8 Uy 1 2 ee uum 14 4 4 Observation sequence with a single filter cccccccccccccecceeeeeeeeeeeeeeeeeeeeeeeees 15 4 5 Observing in multicolour mode sea acassesdoiciaeeadensaneancrtnnntensiadeacsriameaaesteaenaneteeaaeavineas 16 4 5 1 Multicolour mode common exposure tIME ccccccceeeeeesseseececeeeeeeaeeeeees 16 4 5 2 Multicolour mode
7. THE CODE TO THE CAMERA This problem occurs when the next command is used gt download gpsold hex This command will initialize the camera When run the camera will show the process code to download the camera The information is sent and received using an optical fiber If you receive an error message related to the camera connection it might be because there is a bad fiber connection The support astronomer or the night assistant never the astronomer should proceed disconnecting and reconnecting the fibers with special care both in the computer electronics dome and in the tcp computer Be careful with the colours of the fibers as they should not be crossed red to red and black to black 3 FILTER WHEEL AND SHUTTER PROBLEMS It is possible that when initializing the graphical interface or even during the night the system does not properly initialize or refresh the filter wheel and or the shutter If you have the working or idle message in the bottom info line everything is ok If an error message such as shutter calibration error appears please contact the support astronomer or the night assistant who has to proceed as follows 21 TCP user manual 15 11 2012 Log off and log on from the program gt Qtcp15 If the problem stands the system has to be reset Resetting the system 1 exit from the graphical interface killing the process if necessary 2 go to the dome and turn off the electronic racks
8. ast photometry programs do not need to take darks because in windowed mode and with short exposure times less than a minute the readout noise dominates However other observations such as imaging the entire chip for routine programs will need to take darks if the exposure times exceed the minute in winter or 40 seconds in summer 20 TCP user manual 15 11 2012 APPENDIX II Common problems 1 WORKING WITHOUT NETWORK lf there are communication problems between asteroide and tcp the observations can be directly made from the tcp computer In this situation the remote use is limited to the use of a switch to control the mouse and the keyboard from the control room In this case the first steps of the procedure are slightly different in the dome check that the TCP electronic racks are turned on P Set the switches in an appropriate way to pass the keyboard and mouse control to the control room Normally this step is performed by the support astronomer gt Start the TCP computer session username is observer Support Astronomer will give you the password Run command gt startx gt In a terminal run command gt download gpsold hex From this point on proceed as described in page 5 NOTE 7he image displayed on the TCP monitor is only a part of the overall image there is a little zoom effect The real limits are reached by moving the mouse pointer to any side of the image 2 FAILURE TO DOWNLOAD
9. different exposure times for each filter 17 APPBNDPST zxddiuontal NO een eee nn eee et nme er RSEN 20 APPENDIX II Common problems ccc ccesssessssseeeeeccccccceeeeeeeeaaaauseseseseeeeeeeeeeeeees 21 APPENDIX III Pixel size and detector orientation essseeeeeeese 23 TCP user manual 15 11 2012 1 INTRODUCTION The Tromse CCD Photometer TCP is a portable instrument optimized for fast reading photometry Windowed system based on CCD technology The TCP incorporates the possibility of an on line data reduction i e the real time production of light curves and the calculation of the Fourier transforms of the data obtained so far This instrument was built by the Physics Department at the University of Troms Norway see Roy Ostensen s doctoral thesis at http whitedwarf org theses ostensen pdf in collaboration with CUO Copenhagen University Observatory The TCP installed on the IAC80 telescope since 2002 is one of the telescope s common user instruments This document is intended as a detailed guide for using the user interface for data acquisition of TCP Figure 1 TCP The TCP electronics driver was developed by CUO The current version of TCP uses the CCD chip Site Tektronik 1024 x 1024 which operates at a temperature of 40 C below the ambient temperature The pixel size is 24 x 24 microns The chip covers an area of 2 56 by 2 56 cm which is a square fie
10. e Object Name Field 2 for the Right Ascension and field 3 for Declination si Tromso CCD photometer Ba d File Camera Tools View Help _ A K T E m Camera control i Tz 2 3 4 E 5 4 Figure 9 Information Fields of the object gt Once the information has been written it is useful to add it to the list of objects for future observations Press button or add it from the main menu by selecting File Add to list gt Select an object from the list The object information will appear in the fields 1 2 and 3 Click on the button or go to File Get from list in the main menu A new window will be opened with the objects included in the file see Figure 10 To proceed with the selection double click in the object you want to observe SEC TCP user manual 15 11 2012 Target select C1 l Lac 22 39 16 38 03 01 V1 121ac 22 41 28 40 13 32 C2 2And 23 02 36 42 45 28 Va 16Lac 22 41 28 40 13 32 AMC Vn 12 34 54 37 37 0 Ba09 23 15 21 329 5 1 PG2303 243 23 6 17 7 24 32 8 RXJ2117 21 17 8 3 34 12 27 PGOO014 1 1655 4 7 4 32 Figure 10 Selection of the object The user interface will also show the air mass 4 and the sidereal time 5 Please press tab key just after filling each field otherwise the information will be lost and will not be saved in the headers 4 Tromso CCD photometer A 4 zJ Ele Camera Tools View Hep 7 m R E T
11. e a single filter or several filters multicolour mode the technique varies slightly This section will describe what to do to make a sequence of observations using a single filter for example for bias and or flats gt Select the exposure time and select Sequence in the corresponding area Exposure in the left side of the user interface gt Select the Sequence time in the corresponding area Sequence in the left side of the user interface Sequence Sequence Timecs Figure 19 Selecting the sequence time NOTE Sequence time exposure time readout time 23 sec for full frame additional delays due to filter changes and or shutter movements In full frame mode we recommend to add 30 35 additional seconds Write 9999 or 0 in the Frames field of the Sequence area Thus the program will take data continuously until the sequence is aborted C Sequence Sequence Imagen 20 Selection of frame number gt Check that the selected filter is the one requested gt Start observations by clicking the button START area 1 in Figure 10 The first image will begin in the closest multiple to the selected sequence time For example if the sampling time is 20 s and the START button is pressed at 21 30 04 the exposure time of the first image will start at 21 30 20 IF THE SEQUENCE TIME IS TOO MUCH LARGER THIS OPERATION CAN TAKE A LOT OF TIME 15 TCP user
12. e following information box is showed Date ow Time UT 172601 Longitude 16d 30 38 W Latitude 28417 58 N Elevation 2422 0m Satellites Status Figure 6 Info panelof the GPS In this case the GPS is receiving the signal of 4 satellites In case the GPS does not receive any signal contact the support astronomer see Appendix Il problem 4 gt Establish location Thus the information about the observatory telescope and instrument will be saved in the image headers TCP user manual 15 11 2012 a Press File in the main menu and select localisation see Figure 7 left In this option a box with the available observatories and telescopes will be shown see Figure 7 right b Select the telescope IAC80 1 In the Observatory dialog box select Teide observatory at the end of the list 2 In the Telescope dialog box select AC80 Information about longitude latitude and height of the observatory and also about the focal relation of the telescope will be shown 3 Press apply mr Setup Dbservatory Tromso Norway v New Ctri N Latitude 6941 ON Directories gt Te Longitude 1895 0E ta Open Ctr 0 a Elevation 1 0 Targets Time zone DST M3 5 0 M10 5 0 Mis Addtolist Ctri A Get from list Ctrl G Telescope Skibotn 50 Focal ratio 1 2 Instrument Ctr
13. e images shown in this way may give the impression of a defective chip or that the optics is dirty but it is in its main part due to the visualization algorithm On the other side this visualization mode significantly increae the overheads owing to the high RAM memory required for displaying the images Therefore it is not recommended for the full frame mode We recommend to use IRAF to check the images 11 TCP user manual 15 11 2012 d Ihome observer Data Jose NGC246 Ag03 24 25 mh24 flats mh240003 fits File Camera Tools View Help joe NH mam a2 fee f of mo so usa ME m Camera control mj Exposure sec msec b zi fo EE Single shot C Sequence r Sequence Time s J Maulti corour r Transfer made Full frame Windows r Exposure mode C Obiect C Dark C Bias Fat field four 1 47 56 3 who HH 4 nu Done p81 404 25473 10 7 60 8 Figure 15 Example of full frame image filter B flat field with 5 seconds exposure time The display mode is min max EI Ihome observer Data Jose NGC246 Ag03 24 25 mh24iflats mh240003 fits B ri E Bie Camera Tools View Help In AC m Camera control Start Exposure sec msec s lo E Single shot C Sequence Sequence Time s Frames Filter m zi e tautt
14. er red and asteroide computer blue TCP user manual 15 11 2012 gt Start a session in asteroide connect as obstcs1 password ask the support astronomer or the night assistant gt Open a terminal in asteroide and type gt ssh observer tcp ll iac es pass ask the support astronomer or night assistant gt Once in tcp open a new terminal gt xterm amp In the new terminal type gt download gpsold hex This command will initialise the camera When executing the camera will start the process with download code to the camera f there are camera connexion errors please contact the support astronomer Appendix Il problem 2 Running the data acquisition software Qtcp15 gt The display will show the graphical interface of the data acquisition program see Fig 4 The user must check the messages appearing at the bottom left line marked in red during initialization Shutter initialisation and FASU initialisation If all goes well after 2 or 3 seconds the message working or idle should be displayed If the system is having problems initializing the shutter and or FASU a message notification will be displayed In this case you need to contact the Support Astronomer to restart the system Appendix Il Problem 3 Tromso CoD photometer 7 O File Camera Tools View Help joc M E BB ee i a36 o4so02 8 Ea 44 BY EA gt Transfer mode Full f
15. iecorour m Transfer made Full frame Windows m Exposure mode C Obiect C Dark C Bias Flat field for esa AE O uD 23 Figure 16 Same image than Figure 15 but using the Histogram Equalization display mode 12 TCP user manual 15 11 2012 4 1 3 Example 2 bias EI Tromso CCD photometer mj Be Camera Tools View Help joe Bf Camera control Start Exposure sec msec u zj 0 3 Single shot C Sequence Sequence Time s Frames b 3b s Filter b a f mutica _ Transfer mode Full frame gt Windows m Exposure mode C Object C Dark Bias C Fat field lf 11 35 31 1 33 26 Done B84 465 2336 F100 1 2647 Figure 17 Example of full frame image bias 4 1 4 Example 3 Astronomical objects E Ihome observer Data Jose NGC246 Ag03 27 28 mh27 data mh270003 fits File Camera Tools View Help joc BS Camera control Stert Single shot Sequence Frames b sb s Filter N le Multi tatour Transfer mode Full frame C Windows Exposure mode Object Dark Asa a w asj m em uml ll c Dre fBASIIANO ONSITE Figure 18 Central star of the planetary nebula NGC246
16. ilters and use the arrows on the fields located to the right of the filter selection buttons to set the exposure time The sequence will be displayed on the upper field of the window The example of Figure 22 shows the following sequence 5 s image in B filter 8 s image in V filter and 4 s image in R Filter 3 If the exposure times are short there would be problems with the filter change Hence to minimize time losses it is better to compute the sequence times in the following way 17 TCP user manual 15 11 2012 Set the following values in the selection bar left side in the user interface see Figure 24 i Set Exposure to 0 and select the single shot option li Set Sequence time to 0 and Frames to number of filters x 3 e g for a 3 filter sequence Frames has to be set to 9 ii Select the first filter in the sequence and enable the Multicolour option iv Set Full frame in the transfer mode field Start the sequence by pressing the START button Once the sequence has finished open a Terminal go to data directory where there should be number of filters x 3 images and calculate the time spent between two consecutive images related to the same filter For example for a BVR sequence we should take a look to the starting times of w00003 fits and w00000 fits images or w00001 fits and w00004 fits The header file image w00000 fits appears with gt more w00000 fits Find the
17. l P Ctrl Q tcp Filters u Fe B F v Fe Fi F3 F10 Figure 7 Selection of the information telescope observatory instrument that will be saved in the image headers TCP user manual 15 11 2012 3 INFORMATION ABOUT THE OBJECT To enter the information about the object you want to observe there are several steps to follow gt Press the option File Targets in the main menu and select the file Targets st or similar in the main directory m Open Lookin lt gmometobserver O m amp let New Ctrl N Directories k ad erika 0403051730 C mail 1509042200 nit4 1509042203 Lnsmail 1509042208 C xcov24 11609042035 A STABLE_VERSIONS HLP L AMCWn March 4 IACSO filsep aa Data_Fys120 aperrors zd Data Jose Lj aplot lod a Data_old L apsim hex zl Extra L apsold hex L Fv8120 March 4 nvimsrec L HELP files Ga Ragquel_Mar_05 Targets a bin File name targets Ist File type All Files x Cancel Open Ctri Q ca server name Ba Addtolist Ctra Ge t from list Ctrl G r Y Localisation Print Ctrl P Exit Ctri Q Figure 8 Selection of the file for reading and or saving information about the objects to observe If the object is not in the list it can be added by typing the information in the corresponding dialog boxes of the program utilities bar Field 1 for th
18. ld of about 9 2 arc minutes side in the IAC80 It is a back illuminated chip with a high sensitivity in both the red and blue ranges thanks to its special coating The TCP includes its own filter wheel and shutter FASU The FASU was designed with a unidirectional shutter to increase the accuracy of the exposures and a filter wheel that allows installation of up to 6 filters of 50 mm diameter Currently available are the Johnson Bessell filters U B V R and an open position white light Switching between filters takes about 0 5 s allowing the implementation of multiband photometry programs almost simultaneously SC TCP user manual 3 15 11 2012 n 2 STARTING A SESSION The following paragraphs describe the follow up sequence to properly booting and checking out of the system In the dome check that the Electronic Racks of TCP are turned on see Figure 2 Figure 2 Location of the switches of the TCP Electronic Racks gt The TCP computer is located above the FOVIA II monitor see Figure 3 It is normally turned on If not turn it on The computer must be connected to the network If there are problems with the network consult the start up procedure of the TCP computer in Appendix Il Problem 1 The TCP computer is not used directly but through asteroide PC When you finish the process of booting the computer you will have to wait a few minutes to connect from asteroide Figure 3 TCP comput
19. on is displayed by pressing the left mouse button over the image relative position of the cursor number of counts and distance to the centre of the field in arc seconds This information appears in the bottom part of the user interface see Figure 13 10 TCP user manual 15 11 2012 foe 1 35 31 1 39 26 df gunn eq nn ox I an 384 465 2336 100 1 2647 Figure 13 Information obtained by clicking the left mouse button over the image location number of counts and position in arc seconds In the following pages we show the different display options and some image examples flat fields bias and object 4 1 1 Ideal display mode The default image display option is min max but it might be inadequate To change the display mode press the lad button in the utilities menu bar Then the following panel is shown E Scaling F 40960 Scaling C Fixed High foooo T Data Max 1063 Co Min Max Histogram Equalization Preview OK Cancel Figure 14 Display mode selection panel Selecting Histogram Equalization you increase the relative contrast in all the regions of the chip Once this type of image display is chosen it will be set as default Important note This display mode greatly increases the display contrast and sets the grey scale zero level very close to the average bias value with the idea of showing any pixel with some energy over this value Th
20. rame C Windows Exposure mode Obiect C Dark C Bias C Fat field Q smumc s eu 1 20 Working 584 271 0 D 0 0 07 Figure 4 Graphical interface of the TCP data acquisition program TCP user manual 15 11 2012 In Figure 4 we can see that only a part of the area of the chip is displayed There are vertical and horizontal scrollbars to move through the chip On the other hand the overall size of the user interface can be changed by pressing the left mouse button in the lower right corner and while holding down dragging it When Qtcp15 program starts it automatically creates a directory in home observer whose name is the combination of the starting date and time of the program e g 2103042005 21 March 2004 at 20 05 Within this directory Qtcp15 creates a series of sub directories where the program automatically save the different image types taken bias flats darks tcp for full chip images and data for images in windowed mode gt Check that the system is receiving data from the GPS To do this press the satellite button in the top right corner of the user interface see Figure 5 zi Tromso CCD photometer etal Bi Camera Tools View Help a IB a BHI 1 p I jf fj 336 045002 s E3 4 BY i Camera control Figure 5 GPS Information It is imperative that the system receives information from the GPS to work properly If all goes well th
21. see Figure 2 3 turn back on the electronic racks 4 run gt download gpsold hex 5 run back the graphical interface Resetting the system solves the problems in 90 of cases However if the problems remain the camera has to be shutdown the telescope parked to the zenith and the telescope system reset this has to be done by the Support astronomer or the night assistant Very rarely the problem still persists In this case the serial cable that connects the TCP computer with the camera electronics can be wrong or receiving too much noise Check the cable connections and warn MI Instrumental Maintenance to review the status of the cable 4 NO SATELLITES DETECTED If the information box indicates that the GPS does not receive a satellite signal you must contact the support astronomer or night assistant who must proceed as follows Go to the dome and check that the led located over the gosh mark in the electronic rack where the optical fibers are connected is blinking red light If the light blinks then the signal is arriving fine to the electronics but not to the computer Check the connections of the serie cables from the gps yellow box to the computer the cable is labelled as pc at the gps side and clock at the pc side If still does not work reset the system problem 3 If the light does not blink then the electronics is not receiving signal In this case o Log off the graphical interface and turn off
22. ting point read in the logbook the last TCP focus used The focus value for FOVIA II is also different Some values used in March 2010 are Telescope focus 21 760 Filter R FOVIA II focus 12 T1 7 3 In general the TCP focus is 2 000 units larger than the CAMELOT focus gt To focus the TCP not very bright objects V 9 must be taken Select object in the Exposure mode area 4 of the selection window see Figure 12 V filter and an appropriate exposure time for the magnitude of the given object the maximum amount of counts of the star used to focus should not exceed 23 000 counts gt Image analysis will be done from asteroide using IRAF 1 enter as obstcs1 2 open a xgterm 3 run IRAF ec and ds9 4 access to the images directory on TCP The disc is automatically mounted when connected to the tcp computer Once mounted you can access with gt cd tcp 5 Review the focus of the standard way using mexam and making the star contours as circular as possible 6 12 If the image in QTCP15 in IRAF you have to reverse y axis appears decrease focus O increase focus gt Once the best focus is selected please annotate in the logbook the values of the telescope and FOVIA II foci and the temperature of the mirrors 14 TCP user manual 15 11 2012 4 4 Observation sequence with a single filter TCP allows the observer to make sequences of images Depending on whether you are going to us
23. using B filter and 30 s of exposure time This image shows objects until 12 magnitude The image looks somewhat dirty due to the use of the Histogram Equalization display mode 13 TCP user manual 15 11 2012 4 2 Taking BIAS FLATS and DARKS gt BIAS it is recommended to take 5 10 BIAS The number of counts should be less than 2 300 counts pix If this is not the case probably the cooler peltier is not working appropriately In that case please call the Support Astronomer gt FLATS the average number of counts should be between 18 000 and 21 000 counts pix to be sure that they are in the linearity range of the detector If good photometric precision is required it is recommended to take enough number of flats so that the total sum of counts exceeds 100 000 about 5 if the average is 20 000 in each image Combining about 100 000 counts would roughly give a s n ratio 100 which would become the photometric limit If you take dome flats there is a table in the control room showing the exposure times and the lights used to get images with an adequate level of counts with different filters gt DARKS Dark current can be mportant in relatively short exposure times images in this CCD We recommend to take dark exposures for exposures longer than 300 Sec 4 3 Focusing gt Important The TCP focus position is different to the CAMELOT one In the first night some time should be spent in finding the TCP focus As a star
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