KStars is a Desktop Planetarium. It provides an accurate graphical simulation of the night sky, from any location on Earth, at any date and time. The display includes upto 100 million stars, 13,000 deep-sky objects,all 8 planets, the Sun and Moon, and thousands of comets and asteroids.Features

* Catalogs:
o Default catalog consisting of stars to magnitude 8
o Extra catalogs consisting of 100 million stars to magnitude 16
o Downloadable catalogs including Messier Images, Abell Planetary Nebulae
* Corrections for precession, nutation and atmospheric refraction
* Tools for retrieval of data from Online Databases
* Scriptable actions using D-Bus

And more. See website for details.