KStars
Kstars was originally written by Jason Harris and is maintained by a team of dedicated individuals who continue to modify and update it under the terms of the GNU General Public License (GPL), which strives to make this software and its source code freely open to others as long as they make their modifications free open to others, too.
I have just begun to work with Kstars, and I am still learning about KDE and Open Source, so if you have comments or resources that can help me learn more, please send them to me. As I am interested in mythology and history of the stars, my efforts have been in the direction of making new data files available as described below:
hip001.dat contains basic star data for KStars and is located in the /kstars/kstars/data/ directory if you unpack the tarball. If you use Debian, like I do, it is in the /usr/share/apps/kstars/ directory. After many hours of review, I have created a list of suggested changes and have applied them to an updated hip001.dat file that you can download and substitute. Feel free to send me comments.