Stellarium/ stellarium
Stellarium is a free GPL software which renders realistic skies in real time with OpenGL. It is available for Linux/Unix, Windows, macOS and Haiku. With Stellarium, you really see what you can see with your eyes, binoculars or a small telescope.
C++ · C 10k stars
replies in about an hour
31 first-timers merged
Outside contributors get real replies here, and their work gets merged.