New Galexies

[billybob884]

I was curious, how do you make new stars in other galexies? Wait, how do you make stars period?

[mark02]

Well, as far as I know, you are unable to create stars in other galaxies at the present. However, you can create stars called static stars. I had the same problem just recently, not knowing how to create stars, but I just discovered recently the method. It's really quite simple:You must attain a file named a static file, or .stc as mentioned in Celestia. I had to download Rassilon's Pulsar 1257 and Eta Carinae files to see what a static file looks like, because I couldn't create one. Anyway, if you have those two files Rassilon created, you'll see that they contain the code as follows:

# PSR 1257+12
300002 {
RA 195.0405
Dec 12.6667
Distance 2630
SpectralType "R0VI"
AppMag 20
}

Just copy an .stc file from the PSR1257 file, and you can type in your own information. First is the star name, then, in this case, the number (300002) that indicates its Hipparcos catalog number. I'm not quite sure what RA and Dec, or Right Ascention and Declination are, but I think it's the star's position in the sky as viewed from earth. Then you input the star's distance, spectral type, and apparent magnitude. Unfortunately, since PSR 1257+12 isn't a spectral type "R" star, you'll have the incorrect data if ypu download the original PSR1257 file. There is another file Rassilon created called PSR1257 fix (or something like that) that has the correct data, displaying the pulsar as being spectral type "Q" (a new one I suppose) and having an apparent magnitude of 18. Just play around with the apparent magnitude, and the star's absolute magnitude and size can be very variable. Just one more thing: At the end of the starnames.dat file in the data folder, when opened, type in 300002:PSR1257 (it might be 300002::PSR1257, as I don't have my resources with me at the moment) at the very end, corresponding with the star's name in the .stc file, so as to make sure that it is added. I hope this helps clarify things a little .

[Rassilon]

Actually I used red for effect...Q is the correct code to use for a neutron/pulsar just not in the current fix...

[billybob884]

Well, as far as I know, you are unable to create stars in other galaxies at the present. However, you can create stars called static stars. I had the same problem just recently, not knowing how to create stars, but I just discovered recently the method. It's really quite simple:You must attain a file named a static file, or .stc as mentioned in Celestia. I had to download Rassilon's Pulsar 1257 and Eta Carinae files to see what a static file looks like, because I couldn't create one. Anyway, if you have those two files Rassilon created, you'll see that they contain the code as follows:

# PSR 1257+12
300002 {
RA 195.0405
Dec 12.6667
Distance 2630
SpectralType "R0VI"
AppMag 20
}

Just copy an .stc file from the PSR1257 file, and you can type in your own information. First is the star name, then, in this case, the number (300002) that indicates its Hipparcos catalog number. I'm not quite sure what RA and Dec, or Right Ascention and Declination are, but I think it's the star's position in the sky as viewed from earth. Then you input the star's distance, spectral type, and apparent magnitude. Unfortunately, since PSR 1257+12 isn't a spectral type "R" star, you'll have the incorrect data if ypu download the original PSR1257 file. There is another file Rassilon created called PSR1257 fix (or something like that) that has the correct data, displaying the pulsar as being spectral type "Q" (a new one I suppose) and having an apparent magnitude of 18. Just play around with the apparent magnitude, and the star's absolute magnitude and size can be very variable. Just one more thing: At the end of the starnames.dat file in the data folder, when opened, type in 300002:PSR1257 (it might be 300002::PSR1257, as I don't have my resources with me at the moment) at the very end, corresponding with the star's name in the .stc file, so as to make sure that it is added. I hope this helps clarify things a little .

thank you sooo much. so far its working, but im not done yet. what determines the stars size?

[selden]

Mike,

Celestia uses the following formula to determine the radius of a star:
Radius = sqrt (luminosity)* (solar temp/star temp)**2

A star's luminosity is determined from its absolute magnitude (or apparent magnitude and distance).

Celestia uses some lookup tables to determine a star's temperature, depending on the star's class and subclass.

I'll have to refer you to the souce code on SourceForge for the details.

I hope this helps.