Star Catalogues

[Matt c]

Hi everyone I'm new here and I wanted to ask a question about the amount of stars on Celestia. I don't know anything about programming, and was wondering just what it would take to include a catalogue of the size of stellarium for example. Would it be possible to somehow translate the catalogues on that programme over to celestia?

[selden]

Unlike Stellarium, Celestia is a 3D program, so its catalogs need to include the distance to each of the stars, not only the position on the sky. Celestia's primary catalog of about 118,000 stars is based on the distances measured by the Hipparcos astrometric satellite some years ago. Addon Catalogs, containing about 1 or 2 million stars are available on the Celestia MotherLode, down near the bottom of the page at http://www.celestiamotherlode.net/catal ... _stars.php The distances in those catalogs are estimated from spectrographic measurements, and are much less accurate.

p.s. The Gaia astrometric satellite is scheduled to be launched in a few years. It'll make accurate distance measurements of millions of stars. See http://www.esa.int/export/esaSC/120377_index_0_m.html

Unfortunately, we're pretty much stuck with spectrographc guesstimates until then. Accurate direct distance measurements are very difficult from the ground.

[Matt c]

Thank you for the reply selden I suppose it'll be awhile till you can drift through the star clouds of our galactic centre

[selden]

In principle, someone could construct an Addon with simulated clouds of stars, but they wouldn't have the positions of the stars that actually are there. Another issue is the compute and graphics performance needed to actually draw them all!

There are some Addons which portray the couple of dozen stars orbiting the central black hole, but they're a special case.