Star Atlas
KStars is getting better with every release. Originally intended as an educational planetarium program, it now includes stars up to magnitude 7 or 8, which makes it already usable as a star atlas for owners of a small sized telescope.
However, if you want to make real deep sky observations, magnitude 8 is just not detailled enough. And that's the only drawback of KStars; you can add different star catalogi, but there are no detailed ones available. For "professional" use, XEphem is the real pogram to use. I discovered this page, where the Tycho2 and Hipparcos catalogi for use with XEphem can be downloaded. It provides you a star atlas with 2 400 000 stars up to magnitude 13.
However, if you want to make real deep sky observations, magnitude 8 is just not detailled enough. And that's the only drawback of KStars; you can add different star catalogi, but there are no detailed ones available. For "professional" use, XEphem is the real pogram to use. I discovered this page, where the Tycho2 and Hipparcos catalogi for use with XEphem can be downloaded. It provides you a star atlas with 2 400 000 stars up to magnitude 13.