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Changing the radius and texture of Sol

Posted: 24.05.2007, 19:21
by PSUPhysicsStudent
I would like to know how I can change Sol's size and texture. Specifically, I want to replace Sol with Earth. This way I can have the moon as the only orbiting body. This summer's research project will be a lot easier if I can get the Earth/Moon system to act as a solar system with Earth as the Barycenter. Thanks a million!

Posted: 24.05.2007, 20:20
by selden
Do you really want to replace the Solar System?
Or would a separate stellar system do as well?
I suspect a separate system would be more appropriate. Otherwise you'll have to prevent Celestia from using its own solarsys.ssc (e.g. rename it to be solarsys.sscNO).

At any rate, you can replace the Sun by providing an STC file that defines a Star with HIP number 0, just as is done in Celestia's own nearstars.dat

Radius and Texture declarations have been valid in STC files starting with Celestia v1.4.0. For a description of these and other newer STC parameters, see http://www.lepp.cornell.edu/~seb/celest ... eters.html

Posted: 25.05.2007, 13:59
by PSUPhysicsStudent
Hey thanks! I'll try it both ways to see which one will work better. I do prefer editing the solarsys.ssc file because i've done it so many times before and i have never created a new solar system....but....here we go.....!

Posted: 25.05.2007, 14:16
by t00fri
How about resetting the color in your posts to something that is readable!?

Bye Fridger

Posted: 25.05.2007, 14:42
by maxim
t00fri wrote:How about resetting the color in your posts to something that is readable!?



:) Just dropped in after almost a year: Still the same problems as ever... :lol:

Posted: 25.05.2007, 15:25
by PSUPhysicsStudent
I made a file called newstar.stc and put this in it:


star 0 "esun"
{ RA 0
Dec 0
Distance 0.003
Radius 6378
Texture "earth.png"
}

Nothing happened. What am I doing wrong?

BTW Selden, is the cyan color on my posts hard to read to you?

Posted: 25.05.2007, 15:37
by selden
You didn't specify a SpectralType and a magnitude (either AbsMag or AppMag)

[edit]

Yes, cyan is hard to read: I use the subSilver board style, which has a light-blue background. Using the mouse to highlight the text makes it readable, though.

Celestia has two board-style options: subSilver or Solaris. Although it looks attractive at first, the Solaris color scheme is much more tiring than subSilver for long term use.

If you don't specify a color for the text, then the board style code picks the color most appropriate for maximum contrast no matter which board style is being used.

Posted: 25.05.2007, 15:48
by PSUPhysicsStudent
Do i need to tell Celestia that i have a new file called newstar.stc or will it just pick it up during the load at startup?

I did add those other parameters and nothing happened, but here is the current file:


star 0 "esun"
{ RA 0
Dec 0
Distance 0.003
SpectralType "G2V"
AbsMag 4.83
Radius 6378
Texture "earth.png"
}


also, i made sure there is a blank line at the end.

Posted: 25.05.2007, 16:08
by selden
Star needs to be capitalized and the STC file needs to be in /extras/ -- it works on my system.

Posted: 25.05.2007, 16:18
by PSUPhysicsStudent
Fantastic!! It worked. Now how do I get rid of that "corona" effect on the new earth/sun object? Change the SpectralType parameter?

Posted: 25.05.2007, 16:24
by PSUPhysicsStudent
I just took the flare.jpg file and made it all black and it took the starburst effect away but now there is still a corona.

Posted: 25.05.2007, 16:30
by selden
The corona effect is because it's defined as a Star.

A workaround may be to define a very tiny, dim Star and define your central Earth as a planet orbiting the Star, with a Radius much larger than the Star, and with a very tiny SemiMajorAxis (e.g. 1e-32). The star will still 'glow' but the effect will be buried inside the planet.

Posted: 25.05.2007, 16:59
by PSUPhysicsStudent
Selden, I really want to thank you for taking the time to help me. I think I've got it figured out now.

If you would be interested, I would like to show you last summer's project I made. It is a 53MB animation (2 minute AVI) that shows seasonal polar ice migration along with the specular reflection from many different situations. The only thing is....I used the INTEL INDEO codec to capture the video and you'll need it to view the file. I went to get the codec and they want 15 bucks for it now! SHEESH!

Anyway, I think you'll be impressed as to what we got Celestia to do.

Let me know if your interested,
Thanks again,
Charles

XYZ files

Posted: 01.06.2007, 14:44
by PSUPhysicsStudent
Is there a limit to the size, number of lines of data, or number of years that a SampledOrbit (.xyz) file can have?

We have a 10,000 year integration we're trying to get Celestia to read.

Posted: 01.06.2007, 15:20
by selden
I don't think there's any limit other than the total amount of memory on your system. xyz trajectories currently are stored internally as single precision (32bit) values, although Chris is planning to make double precision (64bit) values an option in a future version of Celestia. The values in the trajectory file can be double precision although that precision isn't used yet.