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Celestia User's Guide

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1. v Comet Tails IV Night Side Lights Markers Constellation Borders Orbits TS oe Orbits Labels p Information Text 11 View Options is the 3rd option in the Render menu and an Orbit Label Orbit Label in important one Left click this option to open the View Asteroids v T Moons i Tasa Options dialog box A list of choices will appear Deciding T Comets M T Planets Peta Constellations Spacecraft which ones you want is a personal and a practical choice If Galaxies Stars your computer is a newer model then we recommend the options listed in the image to the right of this paragraph and etes described in detail below If your computer is slower or older pronos 1000000 and Celestia appears to be running slowly deselect some of OK Cancel these options as suggested in the following discussion ie Note Keyboard shortcuts to these options are listed in brackets Atmospheres Ctrl A is the keyboard shortcut to turn Atmospheres on or off toggle Celestia will draw colored atmospheres above all planets and moons that have them You will be able to see them from space and even fly through them As you do the sky will lighten Atmospheres will even dim and turn color as you view them near the terminator near the dark side Highly Recommended but does require computer resources Try turning it off uncheck the box or toggle the key shortcut if Celestia is running too slowly
2. hyperspeed billions of times faster than light c Just keep holding down the A key to speed up The A and Z keys are exponential speed controls As you gain speed the stars will wiz by you like a scene from StarTrek You will quickly be taken out of the Milky Way entirely and into the blackness of the space between the galaxies You can journey to the very edges of Celestia s universe There is not much to look at out there Swing the sky around and you may be able to notice some dim galaxies Generally to see the Milky Way from outside of its confines start your spaceship moving anywhere inside of our solar system press the O key to reverse course accelerate to a warp speed of about 10 ly s light years sec and watch The stars and then the Milky Way itself will begin to recede from you Hit the S stop key and enjoy the view If you are following an object in our solar system press Ctrl K to turn on Markers then press Ctrl P to mark your object A green box will appear in the disc of the Milky Way showing you where our solar system resides To return press the H and G keys or hit Celestia User s Guide 31 of 40 the Q key to reverse course again start your ship moving forward and you will fly back to your point of origin Please remember that Celestia only tracks a tiny few of the over 200 billion stars in the Milky Way Galaxies contain FAR more stars than this program can track Celestia also provides shortcut k
3. Check the error output from configure to determine what s missing install the necessary items and then try rerunning configure If neither the KDE or Gnome versions of Celestia will build try falling back to the GLUT version There are many options for configure you can view them all together with a brief explanation for each by running configure help After running configure compile and install Celestia make make install Celestia User s Guide 9 of 40 Note make install will need to be run as root unless you ve overridden the default install directory by invoking configure with the prefix option Hopefully compilation of Celestia will go smoothly If it does not it s most likely because some required package is missing A relatively common problem is that the OpenGL developer package necessary for building OpenGL applications has not been installed If the compiler complains that gl h or glu h is not found it s a symptom of a missing or improperly installed OpenGL developer package Once make completes without errors you re ready to run Celestia from either your desktop of choice or the command line Uninstall To uninstall Celestia in Windows click the Start button at the bottom left of your screen select Settings then select Control Panel then select Add Remove Programs Locate Celestia in the list that appears and click the button that says Add Remove For Apple LINUX UNIX owners follow your system s uninsta
4. 21 Figure 22 Cassini against stars 800x600 Same scene with Fuzzy Points Same scene with Points enabled resolution Scaled Discs enabled enabled Markers Ctrl K and Ctrl P When enabled by pressing the Ctrl K keys Celestia will draw a small square box around in any object you select and mark To mark an object simply select it with a single or double click of the left mouse eU ee button so that its name appears in the W M t v EY NOTER upper left corner Then right click on it and choose Mark You can also press Ctrl P from the keyboard to mark an object You can mark as many objects as you like Objects not currently selected will have a green mark Current objects will have a red mark To unmark an object right click on it and choose Unmark or press Ctrl P again To turn off all Marks press Ctrl K again Marks are very useful for tracking an object in space that you ve lost sight um 5 ni E Speed 0 000 m s FOV 45 19 12 0 0 42 Radius 10 000 m Figure 23 Voyager 2 marked Celestia User s Guide 18 of 40 of or for highlighting objects so that you can find them easily again For example you can mark the Voyager 2 spacecraft as it speeds alone out of the Solar system No matter where you travel in space you can always see it by scrolling across the sky to locate its mark Note All Marks are erased and reset to zero when the program closes Orbits Labels New The cent
5. Pluto it will list the 500 brightest stars as seen from Pluto 49 Although extrasolar planets have not yet been seen directly or photographed gravitational and other evidence strongly points to their existence To give you an up to date astronomy experience Celestia includes some hypothetical planets that have been placed around candidate stars In addition Celestia s many users have designed fictional solar systems that they have placed around some of the stars in our sky When downloaded their solar systems will appear here in the star browser list also Selecting the With planets option will enable you to locate the stars that have planets including fictional ones Remember though that the star has to be reasonably close to Earth This menu will only display the first 500 stars that have planets If a solar system is far out in space it may not be visible in the list To practice such a journey locate the star 51 Peg in the star browser list make sure you choose the with planets option and select Go To You will fly at great speed to a bright yellow star much like our Sun A planet will be seen near it Either point to it and left click to select it or right click on the star 51 Peg when you get there and select the planet named b Press the G key on the keyboard and you will be taken to the planet which will appear as a big blue green gas world similar to Uranus Using your movement keys as described earlier i
6. To see eclipses you must have Eclipse Shadows selected in the Render Options menu Also note that once you examine an eclipse you will be in a new date in Celestia To return to your current date and time press the Shift key There is a limit to what Celestia can display between dates that are far apart For example Jupiter has 63 moons They all have the capability to pass between Jupiter and the Sun very frequently If you ask Celestia to compute a list of solar eclipses between say 1920 and 1990 the list will become so long that it will lock up the program Therefore when dealing with the four outer gas giant planets of Jupiter Saturn Uranus and Neptune they all have lots of moons please keep your request dates between a narrow range of a year or so Celestia User s Guide 29 of 40 a Although Celestia will try to position you exactly above the eclipse event it doesn t always get it right You may find yourself above an eclipse but not see anything b Once you have activated the Eclipse Finder and gone to view an eclipse the program will attempt to Lock you to the next object you select even if you don t want to be locked For example if you click on a star to select it after viewing an eclipse through the finder Celestia will lock the planet you were watching with the star If you then try to go there or anywhere else the program may stop working If this happens try pressing the Esc key Then try selecting an
7. a feature called Light Travel Time Delay Light travels at a speed of 300 000 kilometers per second The sunlight we see on Earth actually left the Sun eight minutes before it reached your eyes Pressing the key Shift will display the one way light travel time from the camera position to the currently selected object The minus key controls light time delay adjustment if it s turned on a message will appear and the displayed time of day in the upper right hand corner of the screen will have the light time delay subtracted If you move your position the time with move with you Most lists of solar system phenomena give times that include light time delay When observing these events with Celestia automatic light time adjustment is extremely helpful 68 For example if a transit of a moon of Saturn is set to occur at 14 00 hours and you are one light hour away from Saturn pressing the key will reset the time to 13 00 hours so that you can witness the event in real time If you press Home and move closer to Saturn the time will decrease as you approach the planet Note Time delay does not function for stars including our Sun NEW FILE Menu Open Script 69 Pull down the Celestia FILE menu and the first choice will be Open Script A script is a file with a cel extension that commands Celestia to go certain places It can also have text The short Night Sky DEMO you may have taken at the beginning of this document is control
8. above the object at the same position while the object is moving Try comparing the two commands Lock Selection 44 Not available in the Navigation menu but available through a keystroke Shift the Lock command is used in conjunction with other commands to bind two separate celestial objects together in space For example click here to select Jupiter and follow it You will be positioned above Jupiter with its moon Io prominently in front of you Notice that Io is slowly moving in its orbit around Jupiter Now left click once on Io to select it and press the Shift keys The display in the lower right corner will now say Lock Jupiter Io The command will place you in a position that remains stationary above both objects even as they move in space To see that effect click here You will be taken to the same spot with time speeded up and the two objects locked to each other The sky behind them will be moving but your viewpoint will be locked This command is also particularly useful for watching spacecraft orbiting around planets Go to and follow the spacecraft of your choice then left click on the planet below press the Shift keystrokes and the spacecraft will be locked around the planet As it orbits you will have sight of both of them To see what we mean click here You will be locked above Earth with the Hubble Space telescope orbiting below you 45 Note When interacting with an object you ca
9. below for more detail Celestia is also available to Apple Macintosh users running Mac OS X Celestia version 1 3 1 The comments mentioned above for Windows also apply to the Apple version of Celestia You can find the MAC version at http prdownloads sourceforge net celestia celestia osx 1 3 1 1 dmg Celestia version 1 3 2 is available for Linux in two different versions Mandrake and SUSES in a single tarred gzipped source archive at http www shatters net celestia download html Which version you choose to install depends upon which desktop environment you have installed The most polished version of Celestia for Linux requires KDE3 Celestia is not compatible with earlier versions of KDE If you do have KDE3 it s highly recommended that you choose the KDE version of Celestia as it s under the most active development Celestia can also be compiled to use Gnome Gtk although Gnome interface is not up to par with KDE and Windows UI It s still possible to build Celestia even if you don t have either KDE3 or Gnome Required Libraries All versions of Celestia for Linux require that you have OpenGL installed More and more distributions are shipping with OpenGL so if you ve recently installed or re installed Linux there s a good chance that you already have a working OpenGL configuration In order to build Celestia you need to have the OpenGL developers packages installed They should be available on your distribution CD or ftp site
10. desirable If you have such a card Celestia will run smoothly and its graphics will be complete crisp and sharp If is runs too slowly is blurry locks up or objects appear to be moving with jerky motions you may need to locate a faster computer or one with more memory or graphics capability PLEASE READ CAREFULLY Celestia uses the OpenGL API to render 3D graphics In order to get the most from Celestia you should have a modern OpenGL graphics card with the latest drivers from the manufacturer If you have problems running Celestia verify that your graphics card is capable enough to run Celestia and that the drivers are up to date If in doubt about the OpenGL driver download and install a new one It will be available free from your card maker s web site Please Note While a graphic video card might use Open GL processing Celestia does not run well on all such card brands or models Several graphic cards handle images in a manner that Celestia may not control properly To date Celestia s features work best on the video chipsets manufactured by NVIDIA Inc Those video cards sell under the model names GeForce FX and Quadro If a compatible Open GL card is not present in your computer Celestia can still offer you a beautiful space experience but some of its advanced features may not display These include shadows on mountains and craters bump mapping sunlight reflections off water specular highlights shadows of moon ec
11. files graphics and data that the program can use If you choose to download the entire library of over 500 Celestia add ons designed to date by its many contributors they can take up over 4 GB gigabytes of disc space For many people with limited computer memory and or internet download speed that is very large To offer Celestia in a reasonable fashion therefore the basic default program is provided for download with a comprehensive but limited set of files sufficient to experience its capabilities without overtaxing your computer Links web addresses to guide you to the additional add on files available are listed on the web within the User s forum and the Celestia website To fully experience what Celestia has to offer we urge you to seek out and download some of these other add on files At one time the add ons were spread out across over 60 websites Fortunately volunteers have been assembling a central repository for them It is not complete but is growing rapidly Its web address is http www celestiamotherlode net and should be your first stop for add ons Another site with over 100 of the add ons compiled can be found here http celestia myftp org lang en In addition these sites all have add ons to use Jeam tag s add on site In French but all links work Praesepe s Files Texture Foundry Mike s add on list BT s Celestia add ons Celestia basic textures Don s Celestia Central Selden s Resour
12. in the Navigation menu or pressing the C key on the keyboard Double clicking on the object will also center it in your viewscreen 38 If you were orbiting a planet or star when you selected and chose to center a new object you might or might not lose sight of your original object as the viewscreen moved to center the new object To compensate for that possibility Celestia provides the Shift C key combination Pressing both of them together causes the viewscreen to swing to center the new object you selected without losing sight of the original To test this out click here You will be taken to a position behind the Moon with the Earth off to the right Earth has been pre selected but is not yet centered To do so press the C key The view will swing to the right and the Moon will almost move off screen to the left Return to your starting view by clicking the above link again but this time press the Shift C keys together Earth will again center but the Moon will still be fully visible Your view will take up position at a new position behind the Moon This feature is obviously useful if you do not want to lose sight of the original object as you sight and center on a new one Go To Selection G 39 Previously mentioned this command will direct Celestia to go directly to your selection and position you a pre calculated distance above it You can use it with any of the Selection options mentioned here or in the following para
13. is stationary because you are following it To see just how fast it is really traveling in space release your hold on it by pressing the Esc key Hubble will recede from you at over 24 000 mph Now press the F key to again follow Hubble and the G key to go to it Slow down time with the K key to about 1000x slower and release Hubble by pressing the Esc key It will now slowly drift away from you 65 To change a date in Celestia pull down the Time menu and choose Set Time A dialog box will appear with pull down arrows allowing you to reset the date and time The new time will be in Universal Time UT To set the time to the current date and time choose the Set to Current time button in the Set Time dialog box or press the key on the keyboard Note At present you cannot manually reset a date in the future past the year 9999 Resetting a date in the past can be done with this menu command backwards to the year 1800 Dates beyond those boundaries can be reached by speeding up the clock and letting time run 66 Important Note Celestia has programmed some of its spacecraft to appear in space and then actually fall back to Earth disappear on the day that they really did so For example the Russian space station Mir was launched on 02 20 1986 and fell back to earth on 03 21 2001 To see Mir in orbit above the Earth you will have to reset the date to some period between those two dates Light Travel Delay 67 Celestia has
14. key 6 number key 5 number key Shift arrow keys Shift 1 9 Ese Backspace Lock on selected object Point at 2 object and press again to pair the two Chase selected object orientation is based on selection s velocity Track selected object keep selected object centered in view Move closer to object Move farther from object Your view pitches downward also see 8 key on numerical keypad Your view pitches upward also see 2 key on numerical keypad Your view rolls counter clockwise also see 7 key on numerical keypad Your view rolls clockwise also see 9 on numerical keypad on numerical keypad Your view yaws swings to the left on numerical keypad Your view yaws to the right on numerical keypad instantly stops yaw pitch or roll Orbit around the object automatically Look back view rear view Select planets around nearby Sun Cancel hold on object cancel command or script action Cancel current selection Time Functions Keyboard Spacebar Stop or pause time or if paused resume time L Time 10x faster repeat for faster time K Time 10x slower repeat for slower time J Reverse time it flows backward Return to Real Time Shift Set time to the current clock time Shift Display light travel delay between observer and selected object Subtract light travel delay from current simulation time toggle on or off Joystick Functions typical Note joystick buttons differ in fu
15. menu The Location Bookmarks feature is very handy to have and use For example if you have taken some time to position yourself in a particularly good view location in space or at the beginning of a celestial event save that position with a bookmark and you can come back to it or show others the same event by an instant click on the bookmark Cel URLs 80 Celestia makes it possible to share locations and export them out of the program by inserting them in a web page or other document through cel URLs A cel URL is a string of text a hyperlink that contains your current ship location orientation time render options and field of view With it you can take a snapshot of your precise position time and view in space and save it as an external hyperlink a URL If you then paste that text string into a document that recognizes hyperlinks word processors web browsers notepads etc a user clicking on that link will automatically launch their own copy of Celestia and be taken to the exact position in space that you were viewing It can be used anywhere you would use an http hyperlink Obviously the user must have Celestia on their computer for this feature to work For example cel urls have been used extensively in this document to take you to different locations associated with the figures Another example below is a cel url that captures the position of Phobos one of Mar s moons orbiting high above the planet in January 2000 Cl
16. of the screen will be a message telling you that you are Following Earth Wherever it goes you go Thus although Earth is actually moving rapidly through space you are moving with it Field of View Under the Follow Earth text will be your Field of View or FOV setting This is the amount of sky your view takes in Celestia starts you out with an FOV that it calculates based upon your screen size resolution and monitor settings It ranges from 15 to 45 which means your monitor is displaying about 15 45 of the sky most people have a total visual field of 120 However you can change the FOV easily by holding down the Shift key on the keyboard left clicking your mouse button and dragging the mouse forward or backward Try it As the FOV gets smaller the scene enlarges lt is similar to a telescope Celestia User s Guide 11 of 40 magnification You can also press the key or the keys to change field of view from the keyboard Enlarging the FOV allows you to magnify objects in the distance while still keeping the planet in the foreground In general an FOV of about 32 presents a sky view that draws objects at about the size you see them in space If you wish to return to the default FOV that your program opened with and you have a mouse wheel click push the wheel button down once Please note that if you change your screen window size by dragging its borders Celestia may assign and change the FOV base
17. options 10 Display Mode To open the Render menu left click on the word Render at the top of the Celestia view screen and choose Select Display Mode or Toggle Full Screen These are instructions to Celestia to change the resolution of the view screen Choose the Select Display Mode menu first to choose the size of the viewscreen you prefer Windowed Mode is the default choice and sets your screen to the same resolution size your display monitor is set to display For example most desktop computers display a default screen resolution of 800 x 600 pixels while new Win XP systems and laptops are typically set to 1024 x 768 pixels in either 16 or 32 bit color To find out what your computer display is set at right click on your desktop choose properties and settings and read the monitor resolution setting When running Celestia in Windowed Mode your screen gives you visible screen borders sliders and toolbars You can resize the Celestia User s Guide 12 of 40 screen by dragging its corners minimize the screen switch between programs etc If instead you select a different screen resolution from the Display Mode pulldown menu Celestia will immediately switch to Full Screen Mode and draw the screen in that pixel size filling up the entire screen All of the toolbars sliders and side borders will disappear High end computers and those with up to date video cards can take advantage of tighter packed pixel
18. similar In the top left corner will be some information about your target Earth if you see no text press the V key once on your keyboard to turn on your text display Distance gives you the distance from the surface of the object to your viewpoint The Radius of the object will be listed in kilometers NEW The Apparent Diameter will be a value in degrees representing the size of the object in front of you as seen from your current viewpoint If you move closer or farther away from the object its apparent diameter will get larger or smaller respectively In the lower left corner will be your Speed through space At the moment your ship is stopped relative to Earth so your speed is zero Later we will begin to fly on our own and your speed will be listed here In the top right corner will be the current date and time In Astronomy times are given in Universal Time UTC commonly referred to as Greenwich Mean Time and this is what Celestia uses by default If you find it more convenient you can access the Time menu at the top of the program screen and check the box to make Celestia show your local time zone instead The date is listed in the format year month day Note that time will be in 24 hour format Thus 1 00 PM will be 13 00 00 hours Celestia can also speed up or slow down time or travel forward or backward in time with the touch of a button Now you are experiencing the program in Real time In the lower right
19. stars Obviously a key part of the Celestia experience Normally selected no keyboard shortcut Highly Recommended Stars As Discs or Points Ctrl S Celestia can display stars either as points scaled discs or fuzzy points Which looks better is a matter of personal taste and the resolution of your monitor In general a scaled disc forms a prominent circular disc that varies in both diameter and brightness based upon the actual size magnitude and distance of the star from you For example a bright Red Giant star nearer Earth will be a larger reddish disc in the sky with this option enabled while a smaller main sequence yellow star will appear smaller and dimmer in size Scaled discs are not designed to mimic the true visual appearance of the sky Instead they enable you to locate stars by type and magnitude Fuzzy points take a similar approach but draw a smaller more realistic point that varies in size and brightness When your monitor screen resolution is above 800x600 or higher fuzzy points make a clearer distinction between brightnesses of a star and can produce a realistic sky view The 3 option stars displayed as Points tend to be of similar brightness but look better at 800 x 600 and lower resolutions Selecting Points may also make Celestia run faster You can cycle between the three star styles with Ctrl S or you can set the style by using the Star Style sub menu on the Render Menu Figure 20 click here to visit Figure
20. t work you may have to paste the link by inserting a hyperlink See your application software for directions on how to do that You can also link a Cel URL to an image For example right clicking on graphic images in word processing and presentation software will usually offer you the option to insert a hyperlink If you select it paste the Cel URL into the hyperlink address Clicking on the picture itself will then launch Celestia To see this in action return to figure 32 above and this time click once on the image not on the text above it You will be taken to Mars 83 As evidenced in this document Cel URLs are ideal for showing others a particular discovery or position made in the world of Celestia For example perhaps you ve positioned yourself to witness the passing of a Near Earth asteroid as it whizzes past Earth or have assumed a position off the North Pole of the Sun with orbits selected and the entire solar system orbiting below you Saving that location to a cel URL and pasting it on the web or in an e mail for others to activate is an ideal way to share your Celestia experience You ll find cel URLs also used frequently in the Celestia forum 84 Note Be careful using cel URLs with add ons If you save the camera position near a body that is part of an add on you previously installed someone who later clicks on the URL will likely see a very dull view of empty space unless they also have the same add on installe
21. the number the brighter the star Setting this option to Magnitude 6 5 7 5 results is a realistic sky as seen from the surface of Earth on a clear night with only about 3 000 stars visible However if you were living on a space station far above earth s atmosphere you might see stars up to a magnitude of 9 0 or 10 0 with the naked eye Because there are more stars in the sky many Celestia users prefer higher star settings of 8 0 to 10 0 The keyboard shortcuts are very useful here Experiment by using the keyboard key to decrease limiting magnitude fewer stars visible and to increase limiting magnitude more stars visible Note that by turning stars on or off you are changing the amount of data Celestia must process each second If you are experiencing slow performance try reducing the star count Figure 25 Figure 26 peed 0 000 m FOV 45 19 EE Stars at Magnitude setting of 7 5 Same scene at Magnitude setting of 15 0 14 AutoMag Ctrl Y The default download of Celestia actually contains about 100 000 stars up to magnitude 15 0 visible from the vicinity of Earth A setting of 11 0 or more simulates the view you would see through a telescope However millions of stars have been cataloged by Astronomers and if you wish you can download a star database from the Celestia website that contains over 2 00 000 stars You can find it here If this file is loaded and you select the maximum magnitude limit of 15
22. this feature operates exponentially you can move smoothly and rapidly from a distance of one meter to one million light years away from a Celestia object without sacrificing precision at small distances or experiencing long time delays traveling long distances p Press the Shift on the keyboard This is a Lookback command It will reverse your view so that instead of looking forward you will look behind you a rearview window It is very stimulating when flying from one planet to another or traveling in your spaceship You can see forward and then examine your journey from the rear view watching the planet or moon you just left recede from you Joystick Control F8 23 You can also control your movement via a joystick Windows only The commands for joystick control of Celestia are listed in the back of this document in the Keyboard and Mouse Command Summary Press the F8 key to turn Joystick control on or off Celestia User s Guide 24 of 40 Selecting Objects 24 In Celestia you will usually have some object selected If so the program will list its name in the upper left corner It can be a star planet moon asteroid comet spacecraft galaxy nebula or location The simplest way to select most objects is to point at it with your mouse and left click on it note point click does not work with Locations Return to Celestia and try clicking once on a star to select it The information display changes to details about
23. 0 the sky will be ablaze with Celestia User s Guide 20 of 40 stars Note that this level of star display will dramatically slow down even fast computers The choice is yours Fortunately Celestia helps you to set realistic star magnitudes with a feature known as AutoMag To enable AutoMag press the Ctrl Y keys To disable it press them again When Automag is enabled Celestia will turn on or turn off stars to maintain a reasonable visual range whenever you change your field of view FOV It will also restrict the view to a range of 6 0 12 0 A screen display will advise you of your changes 15 Star Style Toggles between scaled disc fuzzy points and points as discussed earlier 16 Ambient Light Shift or Shift 1 On the Render menu select Ambient Light Since space is a near vacuum there is very little light scattered and shadows are completely black You can set the ambient light level to none to simulate this and get the most realistic views of space However there are times when a bit of extra light is useful or aesthetically pleasing For example go to the dark side of any planet and adjust ambient light from None to Low then to Medium You ll discover that portions of a planet s dark side become visible with some light scattering Having a bit of extra light is also good for seeing spacecraft When they re on a planet s dark side they almost disappear in the shadows Low or medium light allows
24. Celestia User s Guide General Instructions For version 1 3 2 Earth from Celestia space click once only to go to this location now Rev 1 3 2 August 28 2004 Frank Gregorio 2003 2004 Celestia User s Guide 2 of 40 Table of Contents Part 1 General Instructions Introduction t CS LES ir C O 3 rudis dbi mm A 5 NEW Scripts and Educational JOUEDIGVS apice aset titel u dl a tutu darth cac e au C esp Oud RM eee 5 Program download and add ons anie Letti tetto aeta be E Dee REL c edu I HH Dese EAE EAE De E peu REEL da ceteeesanlense 5 Computer Hardware Requirements uus cos deae bcoia ose tr tenui Etre iet nar tus corse eee Eed ea aute boten esu tas deus 6 Installation and Uninstallation sen sanigususseactenwesin sees RbRETU rep t PRAET Rabia Aes tea I nid R ocu t E ae anaes 7 General Operation and Keyboard commands esses enne enhn 10 The Opening SOPBOTL cud peer esini e Apad mE Lp taU De ur RD tun cum ma Enn ms UE De EN te EM DEUM E REA MEE Las UE 10 looi E 10 Set Program Options Render Menu ebat pea Pre Pasta db E epee tnt eget ED depu dei Pm rere eer 11 Alternate Textures and Surfaces svi tesemse us nti toan cbe side irte tud pics beam niei aptent Das p N e Ub tsaa 21 halo er P 22 J ys ck Control F8 cto pce
25. IMPORTANT NOTE On occasion we will instruct you to Click here to actually launch a scene in Celestia It is VERY important that you click that link ONLY ONCE If you double click it two separate versions of Celestia will launch Since the program uses a lot of memory and computer resources two programs running at the same time will lock up your computer or slow things down dramatically Note New features since the previous version of this Guide are highlighted in Red Celestia User s Guide 10 of 40 1 The Opening Screen Figure l Earth If you wish you may click here ONCE ONLY to go to Earth 2 3 4 5 6 7 General Operation and Keyboard commands To launch Celestia double click on its icon on your desktop or single click in the Programs menu that appears when you click your Start button The program will load it can take up to 20 seconds to open and will position you out in space The beauty of Celestia is its accuracy The image in front of you is exactly what you would see if you were really positioned in space at that very spot at that particular time In other words Earth Mars and all of the planets moons stars and spacecraft visible on your screen really are located in space where Celestia has put them Earth turns on its axis constantly and is always changing position Thus the screenshot above may or may not be the same scene you see when you open Celestia However it will be
26. Note however that not every image in Celestia is represented by both a high and low resolution image If you tap the R or Shift R keys and nothing happens it just means there is no smaller or larger resolution image of that planet moon asteroid or spacecraft in your Celestia texture files to use Windows Operating System 95 98 ME 2000 NT XP Once you have obtained and downloaded the executable file from the Celestia website simply click twice double click rapidly on its name with your left mouse button The file will begin running and will install Celestia in your C Program Files Directory In general just click Next whenever it asks a question Celestia has its preferred choices and unless you have good reasons for altering them we suggest you follow them Macintosh OS X Operating Systems To install the Macintosh version click on the installation file and follow the on screen menu instructions NOTE Celestia uses a special hyperlink file internally within the program called a cel url file When you click on a cel url the program treats it as a kind of address and will respond by going to a particular place and time in the night sky It is similar to the way web browsers such as Internet Explorer and Netscape go to certain web pages when you click on a hyperlink address In the Windows installation program the install procedure automatically registers Celestia as the program that utilizes cel urls In the A
27. Saturn or one of their moons Please note that if you are in another star s environment or solar system its list of planets moons and space objects will appear in the Browser instead Also please note that the default download of Celestia comes with only a few spacecraft However over 40 other spacecraft are available as add ons from the Celestia add on repository and other sites and will all appear here in the Solar System Browser list if you install them all in your files To get add ons see our prior discussion Celestia User s Guide 28 of 40 Star Browser 47 Select the Navigation menu and choose Star Browser A list of some of the stars being tracked by Celestia will appear Clicking on the column headers at the top of the menu will sort the stars different ways For example if you click on the word Distance Celestia will sort the list of stars by distance from our Sun If instead you click on the column header titled Type Celestia will sort the list according to the star s stellar classification O B A F G K M W 48 The slider at the bottom of the list determines how many stars will appear in the list from just 10 stars to as many as 500 You have your choice of nearest brightest or stars with planets For example if you choose 500 stars with the slider and click the brightest dot Celestia will list the 500 brightest stars in the sky as seen from your current position If you are in orbit around
28. above Speed up time see later discussion and you will see the alignment of planets speeding around the Sun or view the orbits of satellites as they circle around a planet The Orbit Label section of the View Options Menu allows you to turn specific orbit types on or off with a check mark in the box Recommended when desired Does not use much computer resources Figure 17 click here to visit Solar System with planet orbits enabled and time speeded up The inclined orbit is that of Pluto a large Kuiper Belt Object that may have swung into its current orbit through a past collision with another object Spend 0 000 m s Planets Displays all planets as full color detailed textures Most are based on accurate satellite photos of the planets Normally selected no keyboard shortcut Highly Recommended Ring Shadows no keyboard shortcut Celestia can compute and continually redraw the actual position of the shadows a planet s ring will cast on a planet below and conversely the shadow a planet will cast on its rings Highly Recommended but does require significant computer resources Note On some older video cards ring shadows can slow down the program dramatically or lock it up entirely Deselect if your computer is running too slowly Figure 18 Ring Shadows enabled click here to visit Figure 19 Ring Shadows disabled click here to visit Saturn Celestia User s Guide 17 of 40 Stars Displays a sky full of
29. ans of Earth as you actually fly below the clouds See the sky turn a pale blue and eventually transform into the crimson color of a sunset Soar back into space in time to see the lights come on in the cities of Earth and glow an eerie white as the dark side of Earth turns below you Position yourself above the giant gas world of Jupiter and watch as its large moons drift across the face of the planet casting eclipse shadows on its banded clouds and Great Red Spot Hover far beyond Saturn speed up time and count its many moons revolving around its magnificent ringed body like pearls swirling on an invisible necklace Watch as one moon eclipses another Follow along with the spacecraft Cassini as it makes a dramatic rendezvous with Saturn in 2004 Be there to see the Huygens probe detach from Cassini and drop down to mysterious Titan in January 2005 Celestia User s Guide 4 of 40 Journey to the frozen wasteland of Pluto and its moon Charon and imagine their icy coldness as the Sun s faint light casts pale shadows across their cratered ice surfaces Take up station behind the comet Halley set Celestia s clock back in time and follow this famous comet on a trip into the inner Solar System sailing past Earth with its gaseous blue tail streaming out behind it Visit the mysterious new world of Sedna a lonely comet asteroid large enough to be a planet recently discovered orbiting the Sun far beyond Pluto Set your spacecraft spe
30. beacons of light through the nebula gas Travel back in time to witness a re creation of what the Earth looked like billions of years ago Be there as Orpheus a planet the size of Mars crashes into it creating our Moon and sending it into an orbit within a few thousand miles of Earth Travel forward to the year 2800 CE to observe giant mirrors melt the Martian polar ice caps and help to terraform the planet into a verdant world of water plants and cities of the future Drop up to the massive rotating Space Station V from the film 200 a Space Odyssey in the year 2400 CE and see if you can land your Celestia 1 spaceship in its cavernous landing bay Time travel to the future and witness a massive Space Elevator connected by cable to the Earth thousands of km below Visit exotic fictional solar systems complete with orbiting mining colonies wormhole portals in space and scores of planets moons and spacecraft We even have a Dysen Sphere for your viewing pleasure Are you a Star Wars fan The Celestia community has made available for download an entire Star Wars solar system Orbit the planet Tatooine and you will be amazed at the realism of its arid deserts Fly via hyperjump over the ice world Hoth or to the green world of Endor but be careful for tractor beams Somewhere in that solar system will be the giant imperial Deathstar glinting as the light from the system s yellow Sun actually reflects off its evil m
31. before you can view a jpg file your computer must first uncompress it which takes a bit of time PNG files are also somewhat compressed graphic files but they maintain a higher image quality due to the way they save data As a result they do require much more computer memory For example an image save by Celestia would use about 60 KB of RAM memory in jpg format and 360 KB of RAM if saved as a png file If you wish to use a Celestia image in a high quality presentation requiring the best image save the file in png format 74 To view a jpg or png image click on it and your default graphic image viewer or browser in your computer will open it You do not need Celestia running You can paste and view images anywhere you wish Save Movie 75 Celestia gives you the opportunity to create an animation movie of anything you experience in the program s universe For example if you wish to position yourself beyond Jupiter and fly past it at high speed with the planet whizzing by you can record that maneuver in a movie You can record a rare solar eclipse as it happens or demonstrate the occultation of a star by a planetary limb You can execute any command you wish while taping a movie For example you can accelerate in your spaceship move the screen with your mouse zoom in or out speed up time etc In this manner you can set up your own movie demo of celestial places or events for others to see 76 To save a movie file in avi format
32. ce bhp E E E A mei DE 23 Belechms CBIGOUS rrio E EEE Ee EEE EE dim IS NM Md NE 24 Navigation Men M 25 Select Objects by Ey s pc 29 Selecting Objects by Enter Name Enter Method eee eee ee eese ee eee ente e tenente etn nes 20 Lyin your S aes HUD RM TH 30 Telling Where Y OUCATE uccien nien qtti e E E RAA esM aem esi seid ON IDEA IRE Un eR GENS 31 Adjusting Time TIME MENU L K J Spacebar eeeeeenee 31 NEW FILE Wis Op n SCHL RC 32 FILE MENU Saving Images Movies and Locations eese nnn 33 Cel MURG Ssma e e E ES 34 M ltiview VIEW MENU c riiin EEs ECES Er ENAA nE EA TEE E 36 Other Documentation Available s ccsscscctecsedecisatabcndiattnedesiosdedussdenvashebenssausuad vaanacce dassadaddeanesedastenedvenees 36 Credit NEP TM CHEST TORRENT TNT ERES 37 Celestia Keyboard and Mouse Command Summary eene nennen 38 Celestia User s Guide 3 of 40 Introduction to Celestia Many of us have looked up at the stars on a dark night and wondered what it would be like to launch ourselves into space and soar among the stars What do the astronauts of the Space Shuttle really see when they look down upon our beautiful Earth turning slowly below What wonders might we encounter if we could visit Saturn alongside the Cassini spacecraft and sail right through its rings If you have ever wonde
33. ces NASA s Celestia add on files Celestia User s Guide 6 of 40 Celestial Visions Frank s Educational Activities Jack s spacecraft add ons Jim s Celestia page Maxim s site Bob Hegwood s site John s Download site Please note that the above links may be temporary Websites come and go based on member s arrangements with hosting servers However the above sites are an excellent start If I left out someone s add on website please forgive me Remember that there are over 100 such sites scattered throughout the forum To see links to more of them visit and browse the forum at http shatters net forum index php The Celestia default program and package for computers running Microsoft Windows 95 98 ME 2000 XP or NT 4 0 is offered as a fully executable program It will install itself into your computer The current Windows version is 11 6 megabytes in size and is called Celestia win32 1 3 2 exe It is available for download at http www shatters net celestia download html If you have a computer that is less than 2 years old this is the only file you will need to get started If you have an older computer or one with a graphics card with less than 32 megabytes MB of memory see below the Celestia package with low resolution textures is only 4 5 MB in size and may run better on your system You can find it at the same website above Please note that you do not need both of them See hardware comments in the next section
34. common names or Bayer and Flamsteed designations and HD or HIP catalog numbers when entering stars and space objects in all of the Navigation and Enter menus Celestia stores star data taken from the HD catalog but if a star isn t in the HD catalog the HIPPARCOS data set number is used the prefix is HIP Both the 1 name or number and 2 name of the object star can be spelled out or abbreviated 3 letters with a space between them Examples Celestia User s Guide 30 of 40 Upsilon And Ups Andromedae Ups And 51 Peg Note This is 51 Peg not 51Peg 51 Pegasi HD 173739 HIP 5643 Planets moons asteroids and artificial satellites may be named by their common name e g Mir or Jupiter or Io or they can also be specified using Celestia s path syntax Type the name of the star followed by a forward slash then the planet name then the moon or satellite name etc For example 51 Peg b Sol Earth Sol Earth Moon Apollo11 Sol Earth ISS Sol Jupiter Europa Flying your Spaceship 55 What good is a space simulation program if you cannot fly around in it The designers of Celestia have created a seamless and beautiful way to fly through the Celestia universe You are in command of your own hyperdrive spaceship The video screen in front of you is its window You can use this ship to fly through the Solar System chase planets drift above moons try your hand at rendezvousing with spacecraft or visit another star Start some b
35. d Also please note When you click a cel url Celestia must reset your View Options to match the cel url commands the same as in scripts When you are done visiting the location or enjoying the view that the cel url brought you to there is no quick reset command to return your view settings to the way you had them before You will have to open the Render menu and make sure the check boxes you desire are again selected Alternatively you can choose all of the options you desire and create your own cel url hyperlink as a Bookmark Call it Reset Then if someone else s cel url resets your program to settings you do not want simply click on the bookmark and Celestia will reset your parameters and take you to that location Celestia User s Guide 36 of 40 Multiview VIEW MENU 85 Celestia can also show you views from different camera positions simultaneously This can be very helpful for visualizing phenomena like eclipses where you want to watch a view from the Sun the eclipsed planet or moon and the occluding body all at the same time Planetary encounters by spacecraft are another category of events where multiple views can be illuminating 86 When multiple views are enabled one of the views is the active view and is marked by a thin highlighting frame around it All Movement commands will affect just the active view Other commands such as setting the time or date or Render menu commands are global affecting all views New
36. d going to another object We will have a fix soon for these bugs Please be patient Select Objects by Keystroke 51 There is another way to select planets The nine 9 planets in our Solar System have been given numbers from 1 for Mercury to 9 for Pluto The Sun is number 0 To go to one of them you can simply press the number at the top of the keyboard not on the numeric keypad to the right and hit the G key For example pressing 3 and G will take you to the 3 planet Earth If you are in another fictional solar system number keys will also work but it will be that solar system s objects that will be selected If you press the H key then G you will always be taken back to our Sun Sol no matter where you are in the universe Selecting Objects by Enter Name Enter Method 52 You can also select an object or a Location via a convenient keyboard command Hit the Enter key and the Target Name window will appear at the bottom of the screen Type the name of some object you wish to visit such as a planet or moon or star or spacecraft or location As you begin to type Celestia will present you with a list of objects that begin with the letters you are typing For example if you type the letter M Celestia will display a list of up to 12 objects in its data base that begin with an M such as Mars the Moon Mir Mercury etc Note that the program has room to display only 12 objects Celestia therefore starts with all
37. d on the new screen size 8 You can also instruct Celestia to launch the program with a particular starting FOV rather than sizing it based on your screen settings To do so locate the file named start cel which is in the Celestia main Directory folder Right click on it and choose the option that says open with A list of programs on your computer will appear Locate a text editing program such as MS WordPad or Notepad and click OK The start cel file will open and you ll see a set of single line commands in English Locate the line that says set name FOV value ye Remove the symbol and in the space type whatever FOV value you wish For example set name FOV value 32 0 produces a 32 field of view that is about what your eyes would see without a telescope if looking at the Moon or a particular spot in space Save the file close it and launch Celestia The program will now always start with an FOV of 32 Figure 2 click here to visit Figure 3 click here to visit The FOV here is 45 Notice size of the moon behind Earth The FOV here is 12 Earth and moon are now enlarged Set Program Options Render menu 9 When you use Celestia for the first time you will need to choose some options that will tell the program how you want things done Celestia will remember these settings once you initially establish them However during your subsequent use of Celestia you may have need to change or reset these
38. der value this may be useful if the program is running slowly for you Lowering the slider will speed things up Also you may have a scientific need to only see the closest stars to your viewpoint 12 Locations Shift amp under the Render menu is a feature that directs the program to mark and label any city mountain sea valley crater landing site or other feature you desire on a planet or moon and display its name above its latitude and longitudinal position To enable this feature press the Shift amp key Celestia comes with a default list of locations when it is installed onto your computer To toggle the list of features on or off use the menu checkboxes in the Render sub menu However a many new locations files are being developed by Celestia users Some of them are available at http www shatters net claurel celestia files locations and at the Celestia add on repository site at http www celestiamotherlode net index html The forum will also explain how to make your own list of locations To use a Locations list locate and download a list file from the web and place it in your Extras folder in the main Celestia folder in on your computer It will then display when the Locations option is enabled When observing a planet or moon from far away only the largest or most important locations are Celestia User s Guide 19 of 40 shown As you approach it more labels will appear TU A pu 2003 083 05 08 01 Easter S To c
39. e 13 click to visit Figure 14 click to visit Neptune and Milky Way with Galaxies enabled Same scene without Galaxies enabled Night Side Lights Ctrl L Celestia has the ability to light up the night sky From space the thousands of cities across our continents are ablaze with light so bright that they can be seen vividly from hundreds of km up Turning on this option commands Celestia to add those lights to the nighttime vista you see from space above Earth Night textures are also used in some add ons to show fictional cities or volcanic lava flows at night Highly Recommended but does require computer resources Try turning off if Celestia is running too slowly Figure 15 click to visit Figure 16 click to visit Earth Sun and terminator with night lights enabled Same scene without night lights enabled Celestia User s Guide 16 of 40 Orbits O Celestia will draw the actual path of a space object s orbit through the solar system The Option draws orbits of all planets moons comets asteroids and spacecraft that you choose Each orbit type is drawn in a different color with the active orbits in red For example if you are centered on Venus and have planet orbits selected Venus s orbit will be highlighted in red All other planet orbits will be highlighted in blue Orbits are excellent for seeing the celestial mechanics of the solar system Turn them on zoom out from the Sun or planet and view the orbits from
40. e info text U Toggle galaxy rendering Oo Toggle planet orbits I Toggle clouds Toggle Celestial grid Earth based equatorial coordinate sphere Toggle constellation diagrams CtrHA Toggle atmospheres CtrI B Toggle constellation boundaries Ctrl E Toggle eclipse shadows Ctrl L Toggle nightside lights CtrHS Toggle stars as points discs or fuzzy points Ctrl T Toggle comet tails CtrHV Cycle through vertex shading options Ctrl W Toggle wireframe mode displays objects as wireframe models Ctri X Toggle antialias lines mode Ctri Y Toggle autoMag auto adaptation of star visibility to field of view If autoMag OFF Decrease magnitude fewer stars visible If autoMag ON Decrease magnitude at 45 deg field of view If autoMag OFF Increase magnitude more stars visible IfautoMag ON Increase magnitude at 45 deg field of view Shift Decrease ambient light Shift Increase ambient light Alt Enter Toggle full screen display mode on or off Navigation Functions Keyboard H Select the Sun Home C Center on selected object G Goto selected object Ctri G Goto surface of the object F Follow selected object ENTER Select a star or planet by typing its name then press Enter again Y Orbit the selected object at a rate synchronized to its rotation Increase Field Of View FOV 3 Decrease Field of View FOV Celestia User s Guide 39 of 40 Shift Shift T HOME END Up arrow Down arrow Left arrow Right arrow 4 number
41. e interesting objects you can visit in Celestia Select the Tour guide option in the Navigation menu to bring up the guide window choose a destination by clicking on the pulldown arrow and selecting from the list click the Go To button and click OK to close the window You re off We urge you to visit some of these stops on the tour NOTE As you become more experienced with Celestia you can edit this file in your Directory and add your own tour stops Select Object 33 The Navigation Select Object option opens a dialog box that enables you to type the name of an object you wish to visit and then go there Select this option from the menu and in the space provided type Moon and click OK Now hit the G key and you will zoom to an orbit above our Moon Try another space object Note that this option does not work for Locations Goto Object 34 Choosing this option from the Navigation menu opens the Go to Object dialog box There are two uses for this dialog box First it can be used to find your exact position in relationship to objects you may already have selected For example if an object such as the planet Venus is already selected when you choose this option the information fields you see in the Dialog box will contain your current position in relationship to Venus This will include the object s name and your Latitude Longitude and Distance above its surface This is very useful when you are positioned above something a
42. eautiful music playing and your journey can become more stirring Right now your ship is stopped Let s get it moving Click here and you will be positioned about 6 400 km above India 56 Now press and hold down the letter A on the keyboard for a second or two This is the throttle for your spaceship You will begin moving forward Your speed is shown in the lower left of the screen You will start slowly in meters sec As you hold down the A key Celestia increases your speed exponentially Accelerate to between 18 and 20 km s 20 kilometers sec or 43 000 mph which is a bit faster than our fastest spacecraft the Voyagers have ever flown Don t worry about exact speeds just get close Earth will begin getting bigger as you fly toward it on a collision course To change course simply tap the arrow or other movement keys described in step 22 and your view and forward direction will change to a new orientation You will miss and fly by Earth 57 To slow down press or hold down the Z key Your speed will drop the Brake 58 To reverse course instantly simply press the Q key Now you will begin flying away from Earth at the speed you selected Press Q again and you move forward again This command is useful if you overshoot a target Just reverse course and the target will again come into view in front of you 59 To emergency stop press the S key 60 Celestia gives you the opportunity to accelerate to a
43. ed and journey from the Earth s surface up to the International Space Station or the Hubble Space Telescope Test your skill rendezvousing with them as they orbit Earth every 90 minutes Fly out to the very edges of our Solar System locate and follow behind Voyager 1 and 2 as they speed farther and farther away from their creators back on Earth headed on a one way journey through the blackness of frigid space toward distant stars that will take them millions of years to reach Set your ship at faster than light speed and sail to Rigel Kentaurus A and B located 4 3 light years from Earth See if you can find their tiny red dwarf companion Proxima Centauri the closest star to our own Sun or choose to observe rotating sunspots on any of a whopping 2 000 000 other stars drawn by your computer in the Celestia universe to see all of those stars a separate add on is required Download some of the many stunning add ons available for Celestia and your experience becomes filled with even more wonders Visit the Discovery a spaceship from the film 2001 a Space Odyssey dark abandoned and adrift somewhere in Jupiter space with the HAL computer inside Journey to the edges of a massive rotating Black Hole as it spins near its stellar companion Journey to Earth s future and be witness to the end of our planet as a swollen Red Giant sun consumes it Witness a pulsar imbedded deep in the Crab Nebula spinning rapidly as it sends its twin
44. ee Documentation License Version 1 1 or any later version published by the Free Software Foundation with no Invariant Sections with no Front Cover Texts and with no Back Cover Texts A copy of the license is included in GNU Free Documentation License See Keyboard summary on next page Celestia User s Guide 38 of 40 Celestia Keyboard and Mouse Command Summary Print these two pages as a convenient keystroke summary This command summary can also be accessed within Celestia Simply pull down the Help menu and click on Controls Mouse Functions Left click on object select object Right drag orbit the selected object in any direction Left drag orient scene in any direction Rotate Mouse Wheel adjust distance to selection Right Left drag adjust distance to selection Ctrl Left drag adjust distance to selection Shift Left drag change field of view FOV e g gt telescopic view Wheel middle button click toggle field of view between 45 degrees and the previous field e g telescopic view Left double click center selection Right click bring up context select menu Render Functions Keyboard R Decrease texture resolution Shift R Increase texture resolution P Toggle turns on or off planet labels M Toggle moon labels E Toggle galaxy labels B Toggle star labels Ww Toggle asteroid and comet labels N Toggle spacecraft labels Toggle constellation labels amp Toggle Location labels V Toggl
45. esire You may wish to try different choices and determine which one works best for your computer The free DivX video codec available from www divx com provides excellent compression and quality and is quite fast If you want to create many video files with Celestia and are concerned with file size we recommend you download and install DivX onto your computer then save your videos as a compressed DivX file 78 Click OK A red box will now appear on your screen You can move what is in that box by clicking on the screen with your standard movement keys When ready to start taping your movie start time moving forward if it was paused press spacebar again and press the F11 key on the keyboard Recording will begin To stop press the F12 key The recording will stop and the red box will disappear Your movie is saved To cancel a movie at any time simply press the F12 key Save Location BOOKMARKS 79 To save a particular location simply set up your position and time as you would like it pull down the Bookmarks Menu and choose Add Bookmarks Type a name and click OK Celestia will save a positional and time bookmark in its database To return to that location at the exact time you saved simply click on the Bookmarks Menu again whenever you wish choose a saved location from the list and you will go there instantly To delete a location rearrange the list or otherwise organize them use the Organize Bookmarks option in the pulldown
46. et or moon The keyboard shortcut for Sync Orbit is Y Track Selection T 42 This command tells Celestia to track a selected object keeping it centered in view The keyboard shortcut for Track Selection is T To be useful the selected object should first be released from other effects then reacquired and tracked For example if you are currently following and or are centered on Earth first release your hold on it with the Esc key Earth will begin to move away from you at the speed it actually travels in space about 47 100 mph or 78 500 km hr If you watch long enough it would drift off the screen However if you left click on it to re select it and choose the Track Selection command Earth will still be drifting away but your view will swing to center and track it A particular excitement is to chase one of our Celestia User s Guide 27 of 40 interplanetary spacecraft or an asteroid using the Track Selection Command To see this in dramatic action click here You will be taken to a position in space above the asteroid Gaspra You are tracking it and as you watch it coming at you your view will swing as it flies by just missing you and you watch it recede Chase Selection 43 Although not in the Navigation Menu this command is available by pressing the quotation key on the keyboard shift It instructs Celestia to chase a selected object in space It is similar to the Follow command but locks you
47. etallic skin as a huge Star Destroyer and imperial tie fighters keep guard e Approach an entire fleet of Borg Cubes as you command the USS Enterprise E from the StarTrek series These are just a few of Celestia s features Each week new features are being added by Celestia s programmers and other talented contributors It is a program undergoing a rapid evolution in computer graphics Add on features for example will include entirely new solar systems with dozens of planets and moons drawn in vivid detail gaseous nebula clouds new galaxies stars globular clusters and spacecraft both real and imaginary Periodically as new features are added this User s Guide will also be revised If this list above excites you let s get started on our journey into the heart of Celestia Celestia User s Guide 5 of 40 Night Sky Demo Celestia is a stunning program to observe and explore the Solar System and beyond To help you discover some of its beauty and secrets Celestia has a short journey already laid out for you To see it launch the program as described below pull down the Help Menu and select Run Demo When done press the Esc key NEW Scripts and Educational Journeys Celestia developers have created a score of other detailed scripted journeys that take you as an observer to a variety of fascinating places To access and download them visit Celestia s add on repository website at http www celestiamotherlode net index h
48. eys for specific Spaceship speeds F1 Stop F2 Setvelocity to 1 km s F3 Setvelocity to 1 000 km s F4 Set velocity to speed of light F5 Set velocity to 10x the speed of light F6 Set velocity to 1 AU s F7 Set velocity to 1 ly s You can use these shortcuts to get moving at a particular speed then use the A or Z keys to boost or lower your speed further Telling Where You Are 61 Celestia will provide you a general idea of where you are in space by simply looking at the information view display The top left corner identifies which object you ve selected and how far away from it you are By changing objects you can determine a rough estimate of where you are in space However if you have taken up position above a star planet moon etc Celestia will tell you not only how far you are from it but what latitude and longitude above it you are positioned To see that pull down the Navigation menu and select Goto Object As long as you have an object selected you will see your Distance Latitude and Longitude from it If you are completely lost simply go home by pressing the H and G keys Adjusting Time TIME MENU L K J Spacebar 62 Many events in space take place at certain times Planets experience seasons spacecraft are launched and eventually fall back to Earth moons eclipse the Sun on specific dates comets pass by space probes fly by target planets and take their measurements etc Celestia
49. f 40 With higher end cards Celestia gives you five choices for Vertex Shading They are Basic Multitexture Nvidia Combiners Open GL and Open GL Nvidia Combiners The number of these available render paths you can cycle through with Ctrl V depends on the graphics card and driver version you have By default Celestia detects the type of graphics card you have and starts up your program with the highest quality rendering possible If you have an Nvidia Open GL Graphics card all five choices will be offered Using the Ctrl V keyboard shortcut select the last choice Open GL Nvidia Combiners observe Earth and then cycle through the other choices You will see surface shadows and a haze appear or disappear on Earth If you have another brand of graphic accelerator card cycle through whatever choices Celestia presents to you If you have no graphics card at all i e your computer has a minimal built in graphics processor the Basic or Multitexture settings are your only choices Figure 29 click here to visit Figure 30 Open GL Nvidia Combiners render path selected Same scene with Basic render path only Note Keyboard shortcuts for turning on and off toggling the options and features described above along with other keyboard shortcuts are listed in printable format at the end of this document Alternate Textures and Surfaces 19 Celestia comes with a moderate collection of textures graphical files that the program u
50. gives you the opportunity to set a specific date and time or to speed up or slow down the passage of time Your time will appear in the upper right corner of the screen For example to see a planet turning under you simply speed up the clock and it will rotate faster Conversely since objects in space move at thousands of km sec they will disappear from view if you release your hold on them To slow things down a bit and watch them move away you can slow down time 63 You can use the Time menu at the top of the viewscreen to change the passage of time Simply pull down the menu with your mouse and choose an option However most folks use the simple keyboard shortcuts They are Spacebar stop or pause time L Time becomes 10x faster repeat for faster time K Time becomes 10x slower repeat for slower time J Reverses time it flows backward IM Returns to Real Time Shift Sets time to the current clock time 64 For example to see things move faster position yourself hovering above Neptune and several of its moons by clicking here Notice that Neptune is not visibly turning in real time it takes 19 hours to turn once on its Celestia User s Guide 32 of 40 axis Now press the L key twice to speed up time to 100x faster Neptune will visibly turn below you and its moons will noticeably orbit the planet To see how slowing down time can be useful let s visit the Hubble Space Telescope again To do so click here The HST
51. graphical space simulation but into a great one capable of producing a meticulously accurate virtual world of space rivaling the visual quality seen only in Hollywood films They have succeeded As of this writing over 1600 members of the public are part of the Celestia forum community Over 2 2 million people have downloaded the program for use at home or school The list grows daily and includes talented graphic artists computer programmers astronomers astrophysicists planetarium directors animators engineers teachers students professionals from scores of occupations and ordinary citizens in over 25 countries around the world We invite you to join the Celestia forum at http www shatters net forum profile php mode register Celestia is available free of charge for Windows Linux and Mac OS X from http www shatters net celestia download html Hopefully you ve already downloaded Celestia and are ready to install it and experience the beauty of space Here is just a taste of what you will be able to encounter Hover over each of the nine planets in our Solar System as they rotate slowly below you See clouds actually drift by where applicable Look carefully and you may see mountains canyons and craters on the planet surfaces with shadows being cast by them as the Sun sets low on the horizon Take a spin down to the Earth s surface at a lazy speed or at thousands of miles km per hour in your own spacecraft Skim over the oce
52. graphs For example if you select an object with a left mouse click choosing this command from the Navigation menu or pressing the G key as a shortcut will send you directly to the object you selected at high speed If you choose it again or press the G key again you will move closer to the object G is used constantly in Celestia Follow Selection F 40 This menu and keyboard command will direct Celestia to lock onto the object selected and follow it As it moves through space on its orbit you will move also The object can turn below you on its axis if it is rotating so the longitude will change constantly but you will stay the same distance and latitude above it It is routinely used when you wish to take a position in space above a star planet moon asteroid or a spacecraft and is highly recommended The keyboard shortcut for Follow is F and will be used very frequently Sync Orbit Selection Y 41 This feature lets you hover directly over the same position spot above an object that you have selected For example if you are above Earth with Africa below you selecting Syne Orbit will tell Celestia to keep you positioned above Africa all the time As the Earth turns below so will you To see that effect click here Many of our satellites navigation weather spy GPS TV and radio are in synchronous orbit around Earth You can use the command in fact to hover above a particular satellite as it orbits its host plan
53. hange the distance at which particular labels first 1 appear move the slider in the Minimum Labeled Feature Size panel in the Locations sub menu Locations may be manually selected by entering their names see Selecting Objects by Enter Name Enter Method section below Generally you must enter the name of the planet or moon where the location is found as well as the location itself For example to locate and go to Cairo press the Enter key and a sub screen will appear in Celestia with a place to type an entry Type Earth Cairo or Sol Earth Cairo if you are outside the Solar System then press Enter again and the G key to go there You will be taken by the program to a position located directly above Cairo Note that if the 5gs e location is on the opposite side of a planet from where you are Celestia will take a shortcut through the planet and stop above the location you select but facing into space You will have to rotate your view to see the location see later sections for how to rotate your view 13 Stars Visible or On the Render menu select More or Fewer stars visible or toggle with the keyboard shortcuts This tells Celestia how many stars to draw in the sky at one time It controls star numbers by Apparent Magnitude visible brightness You can choose to display only bright stars On the surface of Earth our view generally includes stars of an apparent magnitude of 6 5 or less the lower
54. have and have not aimed their cameras The key toggles between the default interpretive maps and the limit of knowledge textures You can also load them with a right click and selection of Limit of Knowledge from the context menu Movement General movement in Celestia is one of the highlights of this amazing program It is easy and versatile Movement keys are very important for enjoying the Celestia universe For example if you wish to go into an orbit hovering above a planet drop down to its surface or fly in your spaceship to the edge of the Milky Way you will need to change direction orientation and distance in space frequently There are 16 keyboard or mouse general movement commands Let s return to our opening scene of the Earth to do so click here a Right click on the scene in front of you and while holding down the right mouse button move your mouse Right click drag Earth will rotate left right up or down You can view it from any perspective you wish b Left click your mouse and while holding the button down drag the mouse The whole scene will shift as a whole Left click drag c Tap the down arrow on the keypad or 2 on numeric keypad Your view of Earth will pitch upward Before you use the numeric keypad make sure you press the key labeled Num Lock at the top of the numeric keypad If so there should be a little light lit up above the numbers on your keyboard d Tap the up 1 arrow o
55. his concludes the general User s Guide to operating Celestia The Celestia community however has also prepared a variety of other tutorial and manuals that teach you what image files are how Celestia loads and uses them and how data files of various kinds are used to instruct Celestia in what to do and where to do it Look for them under the Documentation link at http www celestiamotherlode net One of our forum members Don Goyette has also written a comprehensive guide that will teach you how to create scripts which are a series of lists that Celestia follows one at a time to take a space journey For example you can design a script to open Celestia orbiting a Red Giant star thousands of light years away Then as you watch your spacecraft will accelerate and fly back to Earth at warp speed You can also insert text messages for the viewer to read It is an excellent tutorial on how to develop scripts You can find it and download it in a variety of formats on his website at SCRIPT GUIDE Celestia User s Guide 37 of 40 Credits This User s Guide was written by Frank Gregorio a high school teacher in Manassas VA Version 1 3 2 Copyright August 2004 Frank Gregorio Celestia courtesy of Developers Chris Laurel Clint Weisbrod Fridger Schrempp Bob Ippolito Christophe Teyssier Deon Ramsey Copyright 2000 2004 Chris Laurel Permission is granted to copy and distribute this document under the terms of the GNU Fr
56. icant computer resources Note On older video cards eclipse shadows may lock up the program Figure 11 click here to visit Figure 12 click here to visit XI e A TX m m 4 ae TW a Io eclipsing Jupiter an example of Eclipse Shadows A total solar eclipse over Africa as seen from space Galaxies U Celestia comes with a galaxy data file that tells the program the position of several galaxies in the night sky and what type they are When this option is selected Celestia will create a small dim sketch of each galaxy and position it in the proper place in space It will also draw the huge band of starry haze we know as the Milky Way Selecting the option therefore will improve your Celestia experience and you will be able to see the Milky Way across the sky and dim galaxies in the distance You can even travel to them in your spaceship However the galaxy sketches are simple and appear as dim blobs Later versions of Celestia will improve on the graphics of galaxies Celestia User s Guide 15 of 40 NEW The Galaxy option also turns on or turns off nebula Nebula add ons such as the famous Orion Nebula or the Rosette Nebula are very popular in Celestia but drawing them can really tax your computer system If you have too many of them positioned in the sky your system will slow down Recommended but does require computer resources Try turning off if Celestia is running too slowly Figur
57. ick on the link below and you will be taken to that exact position time and place in Celestia Celestia User s Guide 35 of 40 Click here for a ticket to Mars Figure 32 image captured via cel URL 81 Please note that cel URLs are hyperlinks You should only click on them once single click not double click In fact if you click one twice it will launch two copies of Celestia at once Since Celestia uses a great deal of computer memory two running programs could lock up your computer If everything seems to stop or slow down after using a cel URL hyperlink or if the screen view does strange things you probably clicked it twice Close one or both of the Celestia programs reclick just once and things should improve 82 To save your position in Celestia as a hyperlink you can use the Bookmarks menu mentioned earlier You can also press either Ctrl C or CtrI INS This will save the hyperlink to your computer clipboard To paste that link into a web browser simply position your cursor in the address field at the top of the browser and press Ctrl V To paste the link into a text document or a PowerPoint presentation you may be able to simply paste the link by positioning the cursor on the page and pressing Paste from the toolbar menu or Ctrl V from the keyboard If successful the link will paste into your document and change color when you hit the Enter key Clicking on it will launch Celestia If that doesn
58. if they re not already installed After you ve successfully built Celestia you will want to be able to run it with hardware 3D acceleration For this you ll need a Linux OpenGL driver from your graphics chipset maker If it s not already installed you ll have to download it from the chipset maker s web site NVIDIA and ATI are the two largest graphics hardware makers and both offer Linux drivers in the drivers section of their web sites Celestia requires the image format libraries libjpeg and libpng both should be present on all up to date Linux installations In order to build the Gnome Gtk version of Celestia the gtkglarea library is necessary It is available at http www student oulu fi jlof gtkglarea if not already installed on your computer Computer Hardware Requirements Celestia is a sophisticated program that not only positions and graphically depicts our complete Solar System in 3D it also plots and tracks a sky full of hundreds of thousands to millions of stars in real time This takes computer power and computer memory Celestia also has available hundreds of add on files Some of them are Celestia User s Guide 7 of 40 large model and graphics files that require lots of RAM memory Thus identifying what level of computer performance you need to enjoy the program depends upon what level of detail you wish to achieve In general to run the basic Celestia program your computer should have a CPU processor that has a speed
59. indows systems or the proper plain text editor for MAC and Linux systems When open locate the line RotateAcceleration 120 and change the number either higher to turn even faster or lower to turn more slowly For example RotateAcceleration 35 will result in your view turning more slowly when you hit a movement key Some users prefer the increased control it gives them particularly if they use the Celestia spaceship NEW You will also find that a variety of other commands in the celestia cfg file can be changed by you to alter the way Celestia does things Read the document s text directions and make any changes you wish After changing save the change by clicking the File and SAVE menu choices and close the document then relaunch Celestia k Right Click Left Click Drag press all together your position will advance toward or recede away from the object 1 Ctrl left Drag same as k above m Roll Center Mouse Wheel if you have one forward or backward same as k above n Press the End key on the keyboard This is the same as k but using the keyboard only Your position above any object will rapidly recede away Hold down the key and you can move light years away o Press the Home key on the keyboard Your selected object will rapidly advance toward you The above five keys resemble a zoom ability However they don t magnify an image they just reposition you toward or away from it Because
60. lected Comet Tails Ctrl T Celestia will accurately place a gaseous comet tail behind all comets properly oriented to always point away from the Sun To see those tails you have to be close enough to the comet Highly Recommended but requires computer resources Try turning off if Celestia is running too slowly Figure 9 Venus and comet Ikaya Zhang in Feb 2002 Click here to visit Celestia User s Guide 14 of 40 Constellations Figure 10 Constellations with borders and labels enabled As viewed from Earth the Sun is in Capricorn Click here to visit Eclipse Shadows Celestia will display both constellation borders Ctrl B and their official shapes for each of the 88 constellations in the sky In the second Options menu section you can also turn on constellation labels These 3 options are useful whenever you have an interest in locating a particular constellation in Celestia Recommended only when desired Does not use much computer resource Ctrl E Celestia can compute the actual position of the shadows a moon or planet will cast on a planet moon as the object passes in front of the Sun a solar eclipse Turning this feature on will cause shadows to be drawn on all planets moons whenever an eclipse occurs It is an elegant feature particularly when observing moon shadows drifting across the giant gas worlds of Jupiter and Saturn Highly Recommended but does require signif
61. led by a script named Demo cel If you have not taken it yet click on the Help menu in Celestia and choose Run Demo Press the Esc key when done 70 Scripts are files written by Celestia developers and users to take you on a particularly interesting journey It controls the program and all you have to do is sit back and watch There are dozens of script files now available You can find many of them as add ons in the Celestia Motherlode website Look for script in the add on definitions If you do download a script place the file into your Celestia main directory or into a folder dedicated to scripts Then to launch run the script simply pull down the Open Script menu from the Celestia User s Guide 33 of 40 Celestia FILE menu navigate to look in the location of the script file and open it For example to open the Demo script navigate to C Program Files Celestia and it will be listed as a file in that Directory 71 NOTE When a script is running it not only controls where you go in Celestia but it also changes some of the Render options that we discussed earlier For example a script may turn off the clouds or turn on Constellation labels in order to explain some particular point When the script is done it may or may not restore your Render options to the way you wanted them We recommend that after a script has run you go back to the Render menu and make sure your preferred options are set just the way you
62. like them FILE MENU Saving Images Movies and Locations 772 Celestia gives you the opportunity to capture and save an image on your screen as an individual graphic file such as the figures seen in this User s Guide You can also save a series of images as a movie file and play it back later in your computer Thirdly if you like a particular location and would like to return to that exact spot and time quickly Celestia can save your location internally within the program as a bookmark or as an external hyperlink which can be pasted into another software program Save Image F10 73 To save a graphic file in jpg or png format simply set up the screen exactly as you want it pull down the File Menu and select Capture Image or press the F10 key A menu will appear Choose the folder you wish to put the file into name the file decide if it is to be saved as a jpg or png file and click SAVE JPG files are common graphic files that have good quality and occupy less computer memory because they are first compressed by the program into a smaller size for storage Compression however always results in some small loss of image quality in exchange for smaller file size Thus jpg images can be convenient to use in e mails websites and documents where quality is not overly critical and too large an image size might slow down the software or make it difficult to transfer over the internet Note however that
63. lipses and atmospheric haze As development of Celestia continues better support for graphics hardware will continue to be introduced If not all the features of your graphics card are supported yet be patient Better yet join the Celestia development team and help improve the program Installation and Uninstallation If you have a video card incorporating a graphics accelerator with at least 32 MB of memory install the full Celestia installation i e celestia win32 1 3 2 exe If your computer is an older model does not have a graphics accelerator or does not support Open GL processing obtain the Celestia package with low resolution textures and install that The views you see in Celestia will be simpler and less detailed but this version of the program and its files require less RAM and it may run more smoothly If you don t know if you have a graphics accelerator card of not download the full version and try running it If things do not run smoothly you may not have such a card Also see the Celestia website for additional troubleshooting at Celestia User s Guide 8 of 40 http www shatters net celestia fag html Alternatively the main Celestia package includes some low resolution image files While running Celestia you can switch from one resolution of graphics to another by tapping the Shift R keys on the keyboard for high resolution or just the R key to change to low resolution images This may speed up your program
64. ll procedure Note In the sections that follow images and screenshots from the program will be displayed Many of these images use higher resolution graphics that are not part of the default download program but which are available from the Celestia forum and other websites as add ons As a result if your version of Celestia does not precisely match the enclosed screenshots don t be alarmed Note In the following Guide many keystroke commands will be referenced All keystrokes will be enclosed inside a square bracket Since all of the letters on a modern keyboard are in capitals e g K or L or M keystroke references will be in capitals also e g K means press the K key You do not have to use the Shift key On occasion however a keystroke will require the use of an actual capital letter such as the capital letter T If that happens we will instruct you to press both the Shift key and the T key For example the instruction will read Press the Shift T keys If the keystroke is a symbol that requires the use of the Shift to reach such as a colon or an asterisk please press the Shift key at the same time as you press the symbol keystroke For example to type the amp sign you would actually press Shift and the 7 key at the top of the keyboard together at the same time Some keystrokes require the use of the Ctrl key or Alt key When they do we will instruct you Ww
65. n choose the Follow Center SyncOrbit Track Chase and Lock commands at any time Center and Track can be used alone or in combination with the other commands The others will execute only the last command given For example if you are Following an object and press the Chase or Sync Orbit command it will replace the Follow command If you press the T Track key however you will both be following and tracking your target object both work together If you type the Esc key the current object will be released from all commands To unlock two objects replace the lock command with another one such as the F command or press the Esc key Solar System Browser 46 At the top of the screen select the Navigation menu and choose Solar System Browser A complete list of all objects being tracked in our Solar System by Celestia will appear Next to planets or moons may be a sign which indicates that around them are more objects to choose from Select any one of them and choose either to Center it or Go To it Centering is useful when you want to see where an object is in space without going to it or when you want to use your spaceship to journey to that planet and you want to locate and center it first Go To is used when you just want to get there fast You should use this navigation menu frequently since it is the complete list of all objects in the solar system including all moons and spacecraft Try it Go to Neptune
66. n paragraph 22 you can move around this tiny solar system Notice that the Solar System Browser in the Navigation Menu is no longer listing our solar system It now lists the one planet system of 51 Peg To return to Earth press H to select the Sun then G to go to it Eclipse Finder 50 The last menu item in the Navigation menu is Eclipse Finder When selected Celestia will calculate and provide you dates of all partial and total solar or lunar eclipses for all planets and moons in its database and offer you the option to go there to witness the eclipse Simply select the type of eclipse solar or lunar the planet and the date range you desire and click Compute When a list comes up pick one click the set date and GoTo the planet button close the dialog box by clicking the Close tab and enjoy the show As an example here is a very exciting double eclipse of Jupiter by two of its moons Io and Europa that took place in January 2003 The shadows of both moons can be seen on Jupiter s clouds Once the eclipse is finished Europa the moon closest to you then eclipses Io the more distant moon To see it click here and watch it unfold by examining both Jupiter and Io All eclipse shadows in space are actually composed of an inner shadow the Umbra and outer shadow the Penumbra Celestia draws both See figure 12 for an example of a total solar eclipse on Earth The Umbra is the darker inner shadow Important Notes
67. n the keypad or 8 on numeric keypad Your view will pitch downward e Tap the left arrow on the keypad or 7 on numeric keypad Your view will rotate roll clockwise f Tap the right arrow on the keypad or 9 on numeric keypad Your view will roll counter clockwise g Tap the 4 key on the numeric keypad of the keyboard The view will swing yaw to the left h Tap the 6 key on the numeric keypad The view will swing yaw to the right as a whole i Tap the 5 key on the numeric keypad to stop all pitch roll and yaw movement Celestia User s Guide 23 of 40 j Hold down the Shift key and press one of the Arrow keys e g Shift You will orbit around the object in view either left right or up down This is convenient to see all of an object quickly Note The speed with which the view turns when you press the above keys is initially set at a particular value 120 in one of the files that Celestia uses to operate That file is called celestia cfg and can be found in the main root directory of the Celestia folder If you find that your view is turning too fast or too slowly for your taste when you press a movement key that document can be opened by you and the Rotate Acceleration turning speed of the above keys can be lowered or increased To do so double click on the file If a menu comes up asking you which program you wish to use to open the document choose WordPad for W
68. nction experiment with yours F8 Enable joystick press again to disable X axis yaw Y axis pitch L trigger roll left button C on a Microsoft Sidewinder Pro R trigger roll right button D Button 1 slower trigger on Microsoft Sidewinder Pro Button 2 faster thumb button on Sidewinder Pro Multiview Functions Keyboard CtrHR Ctrl U TAB DEL Ctrl D Split view vertically Split view horizontally Cycle active view Delete active view Delete all views except active one Spaceship commands Keyboard A Z Q x Sor F1 F2 F3 F4 F5 F6 F7 Increase velocity Decrease velocity Reverse direction Set movement direction toward center of screen Stop Set velocity to 1 km s Set velocity to 1 000 km s Set velocity to speed of light Set velocity to 10x the speed of light Set velocity to 1 AU s Set velocity to 1 ly s Other commands Keyboard D F10 F11 and F12 Run demo Capture image to file Start and stop Movie Save Celestia User s Guide 40 of 40 CtrHINS or Ctrl C Copy location URL to clipboard Windows
69. nd you want to know exactly where that spot is If no object is selected the fields will be blank 35 You can instead change the values and go somewhere else For example type Mars enter 30 for the latitude 5 for the longitude and 5000 km for distance Click GoTo You will be taken to a position 5 000 km above the surface of Mars at 30 N latitude and 5 E Longitude You will automatically be placed in Sync orbit around the object meaning that as it turns you will turn with it so you are always above the spot you desire This is an excellent way to position yourself for eclipse events or above craters etc Please note however that when you arrive you may be on the dark side of a planet In that case you may have to reset the clock to a time when daylight is shining on your position see later discussion or you can move your position to a different longitude 36 Note that Longitudes are values for positions East of 0 E and negative for longitudes West of 0 E For example longitude 40 would be 40 W Distance is distance to the surface of the object Celestia User s Guide 26 of 40 Center Selection C or Shift C 37 This command will direct Celestia to reposition any object that you have previously selected in the center of your viewscreen It is used frequently in Celestia For example if you select a star anywhere in the sky by left clicking on it you can center it by simply choosing this menu command
70. objects closest to you and displays the first 12 it finds in its database As you type the 2 letter in your object s name the list will now display only those objects that contain both letters For example typing Ma will reduce the list to only Mars and perhaps another object you may have as an add on e g the Magellan spacecraft You can complete typing the name or you can simply press the Tab key to cycle the cursor from word to word in the list When you reach the word you desire just press the Enter key again and Celestia will complete the spelling for you auto complete and select the object Now to go there all you have to do is press the G key or use the Home key Try it Press the Enter key and type a single letter A list of objects will appear Type a 2 letter The list will shorten Use the tab key cycle through the remaining objects to any one you wish and press Enter again You will have selected that object Once selected you can use all the object commands such as Center Follow Lock Track Goto etc 53 If you are seeking a named Location on a planet or moon you must enter the name of the planet or moon where the location is found as well as the location itself For example instead of typing simply Cairo you must enter Earth Cairo or Sol Earth Cairo if you re outside the Solar System The slash mark is needed 54 One problem that you may encounter is what to call an object You can use
71. of at least 800 million cycles per second 800 MHz Typically computers bought new within the last 2 years have adequate CPU speeds If your computer is more than 2 years old or is a Pentium III or equivalent with a processor speed slower than 800 MHz Celestia may run slowly and you will be disappointed The basic Celestia program also requires a minimum of 128 megabytes of RAM memory The graphics files that Celestia use are large and if your computer does not have at least 128 MB of RAM Celestia may run very slowly not run at all or may lock up In addition if you wish to explore Celestia s maximum capabilities you will need up to 512 MB of RAM Most importantly the program has become very sophisticated and its many members have added gigabytes of textures and files to it As a result Celestia now really needs a 3D video graphics accelerator in your computer This is hardware circuitry that draws complex graphic images on your video display monitor Graphics cards are available for purchase at any computer electronics store and are easy to install They retail for between 100 and 200 and will dramatically improve your computer s performance in any graphics intensive application Celestia should run with any 3D accelerator card with at least 32 megabytes of video memory However a 64 MB to 128 MB Video RAM card is required if you intend to use Celestia s more detailed graphic files and for the biggest add ons 256 MB of graphics memory is
72. on your system Figure 4 Click here to visit Figure 5 click here to visit E J E M la hs Earth with Atmospheres selected Same scene without Atmospheres selected aam en Celestia User s Guide 13 of 40 Celestial Grid Celestia places an equatorial coordinate grid on the screen showing you the celestial position and direction you are facing in space The grid follows the standard convention of Right Ascension and Declination used in 2003 03 24 15 40 37 CET Astronomy Recommended when needed to gor0 s97 Ai IN ee locate a direction in space For example you CM can turn the grid on temporarily to identify direction of an object in Celestia then go to a real telescope and swing to that approximate coordinate You can also use the Celestial Grid to help you decide where to place a fictional add on or to locate an object whose RA and v REPRE DEC you know from another source Speed 0 008 m s FOV 45 00 0 0 Figure 6 Sky with Celestial grid Enabled Click here to visit Clouds 1 Some of the planets in our Solar System and many fictional planets that Celestia users create in other solar systems have clouds drifting across their surfaces Celestia has the ability to display clouds and put them in motion Highly Recommended but does require computer resources Try turning off if Celestia is running slowly or if you want clear skies Figure 7 click here to visit Figure 8 click here to visit Earth with moving clouds se
73. pple MAC OS X operating system however registration of cel url file links as belonging to Celestia is not automatic You have to do it manually See your OP Help menu for how to register an extension If you do not do this some aspects of Celestia will not work properly For example if you click on a cel URL file without registering it your web browser will launch instead and try to take you out onto the internet You will get a message saying page not found Linux Operating Systems RPM packages are provided for the SuSE and Mandrake distribution You can get them from the SourceForge project page If you run SuSE or Mandrake the preferred way to install Celestia is to get the celestia kde and celestia kde texture packages for your distribution and to install them by running as root in the directory where the files have been downloaded rpm Uvh celestia kde Alternatively or if you don t run one of the supported distribution you can compile Celestia yourself Unpack it and its libraries with gzip and tar via the command gzip dc celestia 1 3 0 tar gz tar xvf Then change directory ed into the newly created directory and configure Celestia Run configure with the appropriate command line for the version that you want to compile KDE Jconfigure with kde Gnome Gtk configure with gtk GLUT configure configure may complain if you are missing a required component or if you have an out of date version of a required component
74. r Right click on Jupiter to bring up a menu of options One of them is Satellites Choose it and a list of Jupiter s moons will appear Left click on any one of them and press the G key to travel to it You can use the right click feature when the object you visit orbits the Sun or planet directly If there is no Satellites option in the menu that appears with a right click that means the planet or moon has nothing else orbiting it All of these keyboard key shortcuts are again summarized in a later section Celestia User s Guide 25 of 40 Navigation Menu 30 Celestia has a complete menu dedicated to space navigation that you can use often Some of the choices are single commands e g Select Sol Others open dialog boxes that give you some choices to make or ask for some input Specifically Select Sol H 31 The Navigation Select Sol menu item directs Celestia to select our Sun called by its Latin name Sol You can select and locate it in space from anywhere even from far outside of our solar system It is very useful to do when you are far from home and simply want to return to our solar system The keyboard shortcut for selecting Sol is H Please note that all you have done at this point is select the Sun You have not gone there or even centered it in your viewscreen To do that you must enter a 2 command as described later below Tour Guide 32 The tour guide opens a pulldown list of a few of the mor
75. ral region in the View Options menu provides you the ability to turn on or off various labels for planets major stars moons etc and to select which orbit paths you want Celestia to draw Turn them on or off as you desire by checking the boxes They do not use much computer power Labels keyboard shortcuts are Toggle constellation labels Toggle prominent star labels Toggle galaxy nebula labels Toggle moon labels Toggle asteroid labels ift W Toggle comet labels Toggle spacecraft labels Toggle planet labels Shift amp Toggle location labels see below we sxszums Information Text This box allows you to choose how much data you want displayed when you select an object Pressing the V key also toggles the information display on or off through two levels of detail If you see no text at all on the screen press V to turn it on Filter Stars This slider determines how many stars Celestia will draw at one time It regulates star number by how far away a star is from your viewpoint By default it is set at 1 000 000 light years Since the diameter of our galaxy the Milky Way is about 100 000 LY across Celestia will draw all stars in its data base at this slider setting However you can lower the slider and command Celestia to draw only closer stars For example if you set the slider to 100 the program will only draw stars that are within 100 light years of Earth Since this requires far less computing power than the highest sli
76. red about these things and would like to find out the answers we of the Celestia community are happy to introduce you to Celestia Celestia is a free real time space simulation that lets you visually experience our universe in three dimensions Celestia was the initial inspiration and creation of Mr Chris Laurel a Seattle WA computer programmer who in 2001 decided to write a free software program to be made available to everyone on the world wide web that would place you in control of a virtual reality world of the Solar System His vision and dedication gave birth to a program that is unlike any other space simulation program in existence Celestia doesn t confine you to the surface of the Earth as many other programs do Instead Chris created a dynamic capability to travel throughout the Solar System and anywhere else in space at any speed at any moment of time and in any direction you choose If you wish you can fly via your own hyperdrive spacecraft to visit stars within the spiral arms of the Milky Way beyond the confines of our Sun You can even travel completely out of the Milky Way galaxy and view it from deep space When Celestia version 1 0 first appeared available for download on the Internet space enthusiasts all over the world discovered and quickly realized the potential of this beautiful program Within a year many talented people worldwide joined Chris in a collaborative volunteer effort to make Celestia into not only a good
77. s displayed Simply click on its name and Celestia will load and draw the Alternative texture To return to the original normal texture right click on the object again choose Alternate Surfaces and select the Normal texture There are times when you might wish to have two alternate textures displayed at the same time representing different bodies For example you might have an image of the Primitive Earth and the Primitive Moon in your texture files and want Celestia to draw both of them together To do this you must locate those files in your Celestia texture folder and name both of those files with the same name For example if you name the Primitive Earth texture Primitive and the primitive Moon texture Primitive and place them in two different folders both will be drawn The step by step procedure for doing this is a bit too complex to cover here in depth A posting on the Celestia forum will help you accomplish this if you so desire Limit of Knowledge Textures Shift and key The surfaces of some of the bodies in our Solar System have only been mapped or photographed incompletely By default Celestia uses surface maps that have the unknown regions filled in with plausible surface features typically cloned from some part of the body that has been imaged But Celestia also includes a set of maps called limit of knowledge textures LOK that depict the unknown areas as blank clearly showing where our spacecraft
78. ses to draw the surfaces of planets moons asteroids spacecraft etc Celestia takes great care to try to include textures that are true and complete or partial photographs of the planet or moon In that way the program s images are impressively accurate However add ons developed by forum members and others are available for download from various websites in the Celestia community that define Alternate Surface maps for some space objects For example you can command Celestia to load an image of the Earth as it may MYCE have looked 4 billion years ago soon after it Dicen formed Its surface will be covered with craters and lava flows Another Alternate Surface available for Earth is this latitude and longitude grid figure 31 that overlays a map of the equator prime meridian Tropics of Cancer and Capricorn etc onto a modern image of the planet A third popular Alternate texture is of Earth at the time of the Ice Ages See the planet covered in ice and the extent of the ice sheet x boundaries Alternate surfaces are also often cae used for global maps of temperature elevation or Figure 3 NYa Si texture other data sesinin 2003 08 30 10 15 52 Fastern St Celestia User s Guide 22 of 40 20 21 22 Only one Alternate surface is displayed at a time To choose an Alternate Surface right click on the object If an Alternate Surface is available has been installed in your program files it will appear in the menu that i
79. set up the screen as you want it and set the time moving forward at the speed you desire We suggest you then temporarily pause time with the Spacebar key while you complete the movie preparations Pull down the File Menu and select Capture Movielmage Choose the folder you wish to put the movie into and type a file name for the movie Then choose the size of the video Celestia User s Guide 34 of 40 Generally 320x240 or 640x480 file are the preferred sizes 320x240 creates a smaller sized image and requires less computer RAM to store 640x480 and higher are larger sized sets of frames and require considerably more RAM Next choose a frame rate We recommend 24 frames per second 24 fps is used in film 25 fps is used for PAL Europe video and 29 97 for NTSC US Canada video 15 fps is often adequate for displaying video on the web The lower the frame rate the smaller is the size of the file that is stored This is something to consider A 2 minute movie can require over 100 MB of RAM when saved in fast and larger frame rates 7T Click SAVE Another menu will appear asking if you wish to save the file compressed or uncompressed A compressed file requires less disk space than an uncompressed file but may not look as good when played back and the process of compressing video can dramatically slow down Celestia Celestia is set to save movie files uncompressed To save a compressed file choose the format you d
80. sizes and more detailed appearance and many users prefer to view Celestia in Full Screen Mode at smaller pixel sizes The screen is uncluttered and your view really looks like the window in a spacecraft For some space scenes the view can be extraordinary However there are disadvantages to Full Screen Mode First in order to access the toolbars you must point your mouse toward the top of the screen and wait for the menu toolbar to be drawn With some video cards the entire screen will go black for a moment as the toolbars are being drawn Secondly some screen modes are simply not designed for certain monitors For example if you set your resolution at 1280x720 on a regular CRT monitor the screen will look warped and the planets will be ellipses not spheres Also be advised that the ability of Celestia to redraw complex scenes in different screen sizes varies from system to system Some users have reported lockups and program crashes when using Full Screen Mode at certain display sizes We recommend you experiment with your own system and choose the resolution that works best for you Alt Enter is a useful keyboard shortcut that toggles between Windowed Mode and Full screen View Options Show Note If you are in Full Screen Mode and wish to toggle between a esi 5 Wise Mus Celestial Grid V Eclipse Shadows Ring Shad Celestia and another program simply press the Alt Tab keys Fetes E T Mei Dc t th M Clouds IV Galaxies Stars ogetner
81. the star Note that you have not actually gone there or changed anything yet You ve simply told Celestia that you have selected a new object if you see no text on the screen type the V key on the keyboard 25 To go to the star you just selected you have four main ways to make the journey practice doing all four A If you right click on the selected star and select Goto Celestia will take you at hyper light speed directly to that star and position you in space at a convenient distance B Alternately you can press the letter G on the keyboard That is the shortcut command for Goto C You can select the star and fly to it in your spaceship It takes longer but sometimes the journey is half the fun of getting there How to operate your spaceship is explained later below D You can also select an object using keyboard commands then use the advance Home key or recede End key to get there To do so simply point at a star or planet left click on it with the mouse so that it is selected and tap both the C and the F keys on the keyboard The C key tells Celestia to center a selected object in the middle of your viewscreen Double clicking quickly on an object will also center it The F key tells Celestia to follow the selected object keeping it the same distance from you even though it is moving through space Let s try it Point at a star left click on it to select it and tap the C key It will s
82. tml and click on the link for Scripts Download the script of your choice and place it in the Celestia main folder which will be usually located on your C drive in your Program Files directory You can then launch it from within Celestia see later instructions The ability of Celestia to educate the public about Astronomy and space has also led to the development of a series of detailed Educational Activities that take Celestia users on a series of detailed virtual tours of the universe Designed for all general audiences and for students in 7 12 grades these Activities teach you a host of facts about specific astronomical topics while employing the stunning power of Celestia to take you there visually They even come with student worksheets that can be printed copied and distributed by teachers to students for a grade and meet all National Educational Standards in Science To access them go to http www celestiamotherlode net index html and click on the link for Educational Program download and add ons Celestia is a computer program written in the computer language C The code is Open Source and may be examined and modified by anyone under the terms of the GNU Public License For experienced programmers who have an interest in improving the program you can find the Celestia source code at http www SourceForge net Click this link Celestia In addition to the actual program Celestia can include many other add on
83. views are created through the keyboard commands of Ctrl U and Ctrl R Ctrl U splits the active view horizontally leaving two identical views side by side Pressing Ctrl R performs a vertical split that gives two vertically stacked views A newly created view can be further split by pressing Ctrl U or Ctrl R again you can continue this until the views become impractically small The TAB key is used to cycle the active view A view that is no longer required may be removed by pressing the Delete DEL key Ctrl D will delete all views except the currently active view 87 Views can also be created and deleted with the coru ai m 2000 02 27 20 46 56 UTC View menu The View menu also contains die k two additional options not available via a keyboard command When checked Show frames puts a frame around each Multiview The other View menu setting is synchronize time Ordinarily time is synchronized between all views but if you deselect time synchronization you can set the current time in each view independently by clicking within the view frame and using the Time menu to change the date or time Turning time synchronization back on resets the time in all views to that of the active view Note that the Follow Sol time rate cannot be set per view the rate p sa 0 000 mis FOV 44 59 59 0 commands and pause affect every view Figure 33 Four Celestia Multiviews seen at once Other Documentation Available T
84. wing and become centered Then press the F key The words Follow _ star s name will appear in the lower right of the screen Now that you are following that object go to it by holding down the advance Home key When you get there back away from the object using the recede End key 26 Go to Surface Ctrl G If you are following an object pressing this key combination will take you directly to the surface looking at the horizon Although it will work for all space objects it s designed for planetary bodies moons etc 27 GO HOME H To return to our Solar System from anywhere in the universe a very useful thing press the H key on the keyboard That will select Sol the Sun Tap the G key and you will be whisked back to our Sun Note You will use these two keystrokes constantly as you explore the Celestia universe and wish to return home 28 To cancel a current selection hit the Backspace key once on the keyboard To cancel a navigation command such as Follow or Track or Center press the Esc key in the upper left of your keyboard You will now be adrift in space Objects will still be selected and you can return to going to them following them or tracking them etc by simply hitting the G F or T keys again 29 Right Click There is another way to select objects and is one you will use often To demonstrate it click here You will be taken to a position above the planet Jupite
85. you to track them better Use Shift to decrease ambient light and Shift to increase it through several step levels Remember that no light scattering None is the accurate view when in space Figure 27 click here to visit Figure 28 Pluto and its moon Charon with Ambient Light set to None Same scene with Ambient Light set to Low 17 Antialiasing Ctrl X On the Render menu select Antialiasing These are instructions to Celestia to use certain graphical processing and smoothing techniques when it draws lines on the viewscreen In general Antialiasing evens out the lines used to draw sharp edges of spacecraft orbit paths and constellation figures Highly Recommended but does require computer resources Try turning off if Celestia is running too slowly Note that anti aliasing may not be available if you do not have a higher quality graphics video card on your computer 18 Vertex Shading Ctrl V Not in the Render menu but controlled via keyboard Vertex Shading is a computer graphics drawing technique that draws renders graphical shades haze shadows specular reflections off of water or ice etc on Celestia objects To see such shading your must have a graphics accelerator card that renders shading via a process known as Open GL However as mentioned earlier not all graphics cards can handle vertex shading properly Celestia now handles Vertex Shading automatically Celestia User s Guide 21 o

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