Celestia Forums

Hello everyone !

I'm new on this forum and I have been admiring Celestia for a few weeks now.

I have observed with great interest that Celestia is able to calculate past and futur positions of solar bodies with, it seems to me, a very good precision.

My question is as follows : does this orbit calculation include movement for stars ?

I would like to be able to go "foreward" a few hundred million years and see what todays constellations look like. I have not tried yet, since I just got the urge, so maybe this is a stupid question.

But maybe it isn't, and I would be quite interested in learning how to model a star's trajectory, or that of a moon or asteroid.

In any case, Celestia is a dream come true. Congratulations !

S.R.

The problem is, that there exist no exact "orbit" calculations that would be required to really make the stars move ... and considering, that celestia only imported thwe hipparcos cataloc, it would be a bit much work to set this up for all stars ;)

Not to mention the trajectory changes of the stars that might occur due to other passing stars.... this feature would be very cool, but I think it'll have to wait for version 10.0.0 !

(mad boris)

It would be a nice feature, to have gravity physics written 100% realistically so Celestia could accurately model the universe.

Writing a ultra realistic physics engine certainly is a lot of work. But then plotting in the orbits for every known object in the universe, that's kinda a hell of a lot more work! just imagine the amount of work required just to the correct movements for all stars in Celestia already.

Is there even a database that tries to list movements of as many stars as it can for our galaxy? It would be full of so many holes and errors, for it to be useful using it in Celestia.

Although entering the movement of just the naked eye stars, wouldn't be such of a challange because they're only a few thousand.

They programmed about 2000 star locactions (Or more)...Things can't get more insane...

Sure, the dynamics model doesn't exist that would allow us to model star motion confidently over very long times; nevertheless, to see what happens to the constellations over, say, the next ten thousand years or so, it might be good enough to assume straight-line motion. This is something that some other astronomy programs such as RedShift can do.

For many relatively nearby stars there is good proper-motion data, and radial motion is known very precisely via Doppler shift. I think it would be especially cool to look at moving star clusters like the Hyades and Pleiades in 3D, since a combination of moving clusters and perspective effects is one of the ways astronomers calibrate the scale of stellar distances.

The motions of many stars are known in two dimensions, but only for a much smaller number of those do we also have accurate radial velocity measurements. Having a complete three dimensional velocity vector is important for a simulation like Celestia where you're not restricted to an Earth based perspective. There are also some programming related reasons that the stars are fixed, although it's easier to get around those than the lack of data.

--Chris