Celestia Forums

Hello folks, I've got a quick question for you.
Is there any way to give stars orbits, similar to the way that planets have orbits? If so, how?
There are some decent sources for orbital data on stars out there, but I can't figure out if Celestial can deal with adding that information or not.

Thanks!

Yes, some stellar orbits are already included in the default distribution (not sure which version they were introduced in, but certainly 1.6.1 has them!)

E.g. Alpha Centauri

Star orbits use many of the same declarations as planet orbits.
For details, see http://en.wikibooks.org/wiki/Celestia/STC_File

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I'm not really talking about binary systems though (eg.: Alpha Centauri).
I'm referring to giving the Sun (Sol) and orbit, along with say... Bernard's star, Sirius, 61 Cygni, etc...
I suppose that I'd need to define a barycenter for the galaxy somewhere, as well. ???

john Van Vliet wrote:a note for tomorrow
wikipedia will be offline 12:00 midnight tue./wed. to 12:00 midnight wed./thur. EST
in protest of SOPA / PIPA

this might include wikibooks also

Thanks for the "heads up" John.
FYI, Wikipedia just went black about 10 mins ago for me. Wikibooks seems to be still available though.

You all don't need to worry, this does not contain wikibooks. Wikibooks is still working, only Wikipedia is shut down

ohms law wrote:I'm not really talking about binary systems though (eg.: Alpha Centauri).
I'm referring to giving the Sun (Sol) and orbit, along with say... Bernard's star, Sirius, 61 Cygni, etc...
I suppose that I'd need to define a barycenter for the galaxy somewhere, as well. ???

You could write orbits for all of them. Celestia does not include proper motions, but, in principle, they could be approximated by using a Barycenter at the galactic center. They'd be a little awkward because distance units for orbits are AU.

Bear in mind that stars do not actually follow Keplerian orbits around the galactic center, though. Stars also go up and down relative to the galactic plane, but that's a relatively slow change of direction.

I realize that they're not going to be very correct, but something is better than nothing to me.
I just wanted to know if adding a galactic barycenter and giving a star an orbit would crash the program or something similar before running off and doing all of that annoying data entry, you know?
(actually, I was hoping that someone had already done it, but... such is life)

I'd suggest doing only a few stars to begin with, so you can be sure you're doing the correct coordinate and unit transformations. For ease of debugging, I'd also suggest minimizing the other Addons you have loaded. so Celestia restarts as quickly as possible.

You shouldn't be tentative about trying things just because you think it might crash the program. Celestia's just a display program. Crashing Celestia won't damage anything since all of its catalogs are read-only. The only writing that Celestia does on its own is to record its current settings when it exits cleanly. If it crashes, it simply doesn't write them. Crashing Celestia is quite rare these days, anyhow, unless you're writing Lua code for ScriptedOrbits. Lua is quite unforgiving. Most crashes are caused by buggy graphics drivers, rather than bugs in Celestia's own code. They tend to happen when there are many large, complex Addons loaded, to the extent that the graphics drivers and hardware can't handle them.