Graphics1. The Earth and other planets look strange. They have weird colors or do not look like globes. How can I fix this?Answer:
Your graphics drivers might be incompatible with Celestia. Try the following, in this order:
2. Celestia is drawing planets and moons bright red. Why?Answer:
- Update the graphics drivers to the most recent version. See section »Installation of new graphic card drivers on Windows«.
- Switch to "Basic" or "MultiTexture" render paths: type [Ctrl+V] several times.
- Disable Celestia's vertex shaders: edit celestia.cfg (with a plain text editor) to remove the # at the start of this line
Code: Select all
# IgnoreGLExtensions [ "GL_ARB_vertex_program" ]
- Disable 3D hardware graphics acceleration. You find that under Windows in the display properties.
- If none of these work for you, please ask for help in the Celestia Help Forum.
Your computer's graphics drivers are obsolete. Celestia makes use of the most advanced features of OpenGL that the graphics driver claims to support. Modern drivers require that the program (Celestia) specifies the version of vertex shader routines that it uses. Obsolete drivers don't recognize that specification. When vertex shaders generate an error message, Celestia draws the object bright red.Solution:
Download and install current drivers for free from the Web site of the manufacturer of your graphics hardware.
If you are using Windows make sure that you have disabled the feature to download graphics drivers from Microsoft. Those drivers have an outdated version of OpenGL included. Always use graphic card drivers from either the graphics card manufacturer or better directly from graphics chip manufacturer (i.e. NVIDIA, ATI/AMD, Intel, ...).
Whenever you upgrade Microsoft's DirectX software, you must upgrade or reinstall the graphics hardware manufacturer's graphics drivers afterward. Installing DirectX installs Microsoft's copies of the drivers, which usually are several generations old.
For correct installation of drivers see point »Installation of new graphic card drivers on Windows
«.a) For PCs running Windows with plugin graphics cards,
you can download the drivers for free from the Web site of the manufacturer of your graphics card. Make sure full hardware acceleration is enabled in your display properties.b) For laptops and desktops running Windows with embedded graphics chipsets,
you usually must download the most recent drivers from the Web site of the manufacturer of your computer. Sometimes generic drivers are available from the manufacturer of the graphics chipset.c) For Apple PPC and Intel computers running MacOS X,
you must upgrade to the most recent version of the operating system. Updated drivers usually are not available separately.
Apple's OpenGL on MacOS X often has serious bugs which sometimes are not fixed in the most recent release of MacOS. You must report those problems to Apple, otherwise they will not get fixed.d) For computers running Linux,
you usually can download the drivers for free from the Web site of the manufacturer of your graphics card.
ATI's fglrx drivers for Linux often have serious bugs. Try to use the driver shipped with the most recent version of Xorg's X server software.3. The Moon is purple, blue and red. Why?Answer:
Your graphics chipset and its OpenGL drivers aren't drawing bumpmaps and normalmaps properly: their OpenGL routine "GL_ARB_vertex_program" is defective. (This is often seen with the newer Intel graphics chips.)Solution:
Install an updated graphics driver or try the workarounds described below.Workaround 1:
Turn off Celestia's advanced display features.
several times to select "Basic
" or "Multitexture
" render paths instead of the OpenGL Vertex programs. This disables the use of vertex and shading programs temporarily. If this does improve things after you've followed the previous suggestions, then you need to do the next step:Workaround 2:
Tell Celestia to ignore specific features that your OpenGL library claims (falsely) to support.
To do this, edit celestia.cfg. Remove the # that's in front of the line
Code: Select all
# IgnoreGLExtensions [ "GL_ARB_vertex_program" ]
(This avoids system lockups experienced under MacOS X 10.3.5 with ATI cards, and purple moons with Intel chips, for example. Intel chips don't have support for some of the graphics routines used by Celestia.)
Celestia's Help menu "OpenGL Info...
" lists all of the routines in your OpenGL library. You might consider adding equivalent IgnoreGLExtensions lines for other suspicious routines.4. I want to see all possible Celestia eye candy. What kind of graphics card should I get?Answer:
The short answer is the following:
Any graphics card with at least 128MB of memory and support for OpenGL 2.0 pixel shaders will be able to show everything that Celestia is visually capable of.
Look for a graphics card that advertises either support for Direct3D shader model 2.0 or higher. Almost all graphics cards being sold today meet this requirement, albeit with varying degrees of performance. High-end NVIDIA and ATI cards will provide the best experience in Celestia. NVIDIA's OpenGL drivers have tended to have fewer bugs than ATI's.Here are some recommendations for cards:ATI Radeon HD series
GeForce 8xxx, 9xxx, and GTX 200 series5. How will Celestia perform on my system?Answer:a)
Only NVIDIA 5000 series or greater (e.g. 6000, 7000, 8000, 9000, 250) cards with 128MB of memory or more will show all of the eye candy drawn by Celestia v1.4.0 or later.
ATI Radeon 9500 and above, including the X series, are comparable to NVIDIA FX 5nnn series cards in functionality, although performance differs. However, not all of the eye candy drawn by Celestia is compatible with them.b)
Graphics cards with drivers that support OpenGL v2.0 will show all. Graphics cards that support only v1.4 will show most, but not all, eye candy.
E.g. NVIDIA GF4 Ti 4xxx series cards cannot show smooth shadow borders. Starting with Celestia v1.4.0, smooth shadow borders can be drawn by any card which supports OpenGL v2.0.c)
Other cards work, but with various additional limitations.Some specific limitations:
- NVIDIA MX cards cannot shadows of rings on planets, although they can draw shadows of planets on rings.
- ATI Rage cards cannot show specular highlights or bumpmap shadows.
- Textures on Rings, 3D Mesh models, and moving Clouds are limited to the size of your card's texture buffer. This limitation does not apply to the surface textures of spherical planets and moons.
Most ATI cards, including the X series, cannot show surface texture images larger than 2K (2048 pixels on the longer side) on a side on Rings, on 3D Mesh models, or on moving Clouds. Unfortunately, some addons include 4K (4048) pixel textures. Those addons only work with NVIDIA 4nnn, 5nnn, 6nnn and 7nnn cards and with ATI X1800 and above with ATI's most recent graphics drivers. Those cards have 4K texture buffers.
In order for Celestia to be able to show bumpmap shadows and specular reflections, your card's OpenGL library must support OpenGL v1.4. In particular, it needs to include "GL_ARB_vertex_program".6. Why does the illumination level in Celestia not fall off the farther from the Sun I go – surely it should be very dark by the time I get to Pluto?Answer:
The human eye can adapt to a very wide range of illuminations, so it wouldn't be as dark out there as you think – about the level of moderate indoor lighting, in which you can see very well. At the other end of the scale, your computer monitor is physically incapable of generating the brightness of illumination that pertains on the inner planets. Fortunately it doesn't need to, since all that would happen would be that your pupils would constrict to reduce the incoming light to a more comfortable level.So in summary: a)
There's no way Celestia can display "realistic" brightness on your computer screen,b)
such "realism" is unnecessary because your eyes merely adapt to compensate.7. Celestia's galaxies are ugly, dim, grey blobs. How can I get colorful galaxies that look like the real things?Answer:
The real things are
dim, grey blobs. Your eyes are not sensitive to color at the very low light levels emitted by distant galaxies.
Many of the colorful pictures you're used to seeing are enhanced by long exposures on sensitive color film. Others are imaginative "false color" combinations of narrow-band CCD images designed to make visible the specific features of interest to the investigator. The colors of those pictures aren't realistic at all.Solution:
You can add a colorful object to Celestia by creating a 3DS model with appropriate images as surface textures. Define it as a Nebula in a DSC file. Use the Search command in the Celestia "Development" and "Add-On" forums to find examples.
Galaxy brightness can be increased by typing a [)]
(Shift+0) or decreased by typing a [(]
(Shift+9) (on english keyboard layout).8. Positions on Mars are on the opposite side of the planet or bumps seem to be half a world away from the mountains or it's dark where it should be daylight. Why?Answer:
You have a misaligned map.
Celestia requires that all maps have 0 degrees of longitude in the center, with 180 degrees of longitude at the edges. All of the surface texture image maps of all of the moons and planets that come with Celestia have this alignment.
In contrast, many maps of Mars were created with 0 degrees of longitude at the left and right edges, and with 180 degrees of longitude in the center.
Using a map with 0 at the edge would cause the symptoms you describe.Solution:
You need to find a map that's properly aligned or you need to cut the map in half and exchange the halves.
For example with Photoshop's 'Offset
' filter is quite easy to modify maps that are misaligned by 180 degrees. In Photoshop CS2, select Filter/Other/Offset
and set the horizontal offset amount to half the texture width.9. Why are some texture maps upside down and backward?I compared the Celestia textures for Venus, Ida and Miranda with some I found in a book or on the Web, and Celestia's maps are upside down.Answer:
Many sources for planetary maps (such as the USGS) use a mapping convention called "ecliptic north" – the north pole of any planet or asteroid is defined as being whichever rotational pole points north of the plane of the ecliptic (the plane of the Earth's orbit around the Sun). Each planet or asteroid can then be classified as a "direct" rotator, if it rotates in the same direction as the Earth when observed from above its north pole (i.e. counterclockwise); or as a "retrograde" rotator, if it rotates in the opposite direction.
In contrast, Celestia uses an equally valid mapping convention called "rotational north" – north is defined as being the pole around which the planet appears to rotate counterclockwise, irrespective of that pole's orientation relative to the ecliptic.
For direct rotators, this difference is irrelevant – "north" turns out to be the same direction in both mapping conventions. But for retrograde rotators, Celestia's north pole corresponds to ecliptic south – so you will find many maps of retrograde rotators like Venus, Ida and the moons of Uranus that appear to be upside down relative to those in Celestia. Solution:
If you want to convert such maps for use in Celestia, you'll have to turn them through 180 degrees.10. My planet's rings are drawn as a featureless oval. It used to work. What's wrong?Answer:
You need to use a smaller ring image, one that is no wider than the maximum texture size supported by your graphics card. To find out how big this size is, use the "OpenGL Info...
" option in Celestia's help menu. Near the beginning it has a line that starts with "Max texture size:".
For most graphics cards, the texture size limit is at least 2048.Solution:
You need to use a smaller ring image, one that is no wider than the maximum texture size supported by your graphics card. 11. Problem on Ubuntu: Why does Celestia not have textures?Answer:
The version of Celestia supplied in the package manager or the Add/Remove programs
menu is broken. Celestia's textures are included in the package celestia-common-nonfree which is not listed as a dependency of the main program, so is not installed by default. Solution:
To fix this issue, either install the celestia-common-nonfree package through the package manager, or type in a terminal window
12. Older issues that should be solved.These issues shouldn't normally happen with the recent Celestia version. But just in case IF they happen anyway, here are the solutions.Sometimes when Celestia captures an image of its window, there's an ugly bright rectangle in the picture. How can I get rid of it?Answer:
Code: Select all
sudo apt-get install celestia-common-nonfree
Sometimes a bright area is recorded where the file requestor menu or any other window overlaps Celestia's main window.
This bug seems to be fixed since Celestia v1.4.0, but if it happens here are some tips for avoiding this problem.Solution:a)
The problem will often go away if you toggle "Show Galaxies" off and on again before you take your snapshot.
Either use the Render/View Options
menu or type the letter [U]
twice before you press [F10]
Run Celestia in windowed mode, not full-screen. Drag the file requestor away from in front of the main window before you click on "Save".c)
If your graphics card supports it, you can connect a secondary display. Some CRTs are very inexpensive. Drag the file requestor to the other screen.d)
Use an external screen-dump command or program.
Windows includes a "print-screen
" command. Under XP, you can use the keyboard combination [Ctrl+Print-Screen]
to write the screen image to the clipboard. You can then use any Paint program and Paste the image into it.Sometimes a screenshot captured in Celestia will have multiple boxes around it, as if Multiview was on. How can I get rid of it?Answer:
This is a bug in Celestia. Solution:
To make a good clean screenshot image, press [Ctrl+D]
before you capture the image. This cancels Multiview.When I try to capture a picture or movie, the image is stretched out of proportion.Answer:
This sounds like a bug with anti-aliasing with older cards/drivers. Here are three things you can try...
- Check the OpenGL anti-aliasing setting of your graphics card. If it is on, try turning it off, or setting it to another option. This seems unrelated to the anti-aliasing setting inside of Celestia.
- Set your graphics card OpenGL options to "default".
- Get the most recent drivers for your graphics card.