Stellarium

Stellarium is a useful and free GPL software that renders realistic skies in real time with openGL. It is available for Linux/Unix, Windows and MacOSX. With Stellarium, you really see what you can see with your eyes, binoculars or a small telescope.

Basic controls :
- Look around by mousedragging, or moving your mouse against the edges of the window
- Time control: forward, backward, return to present
- Zoom
- Tabbed configuration windows
- Text user interface: minimalistic menu for use with dome projections
- Clickable world cities map to set coordinates
- Save your default location

Observation :
- All stars from the Hipparcos catalogue
- The planets of our solar system, and their natural satellites
- All Messier objects
- All NGC objects
- Planet orbits
- Cardinal points
- Azimuthal grid
- Equatorial grid
- Ecliptica
- Equator line
- Meridian line
- Moon scaling
- Object trails
- Asterisms and names of the constellations
- Constellation boundaries
- Compensation for light travel time
- Equatorial/azimuthal mount
- FOV
- Disc viewport
- Observation from another planet, and as solar system observator

Landscapes :
- Fisheye projection
- "old_style" projection, i.e. a ground texture and a number of side textures
- Spherical panorama projection

Viewing :
- Constellation art for the 88 Western constellations stemming from Greek mythology, and 11 for the Inuit sky culture
- Realistic atmosphere
- Fog near the earth's surface
- Star twinkling
- Meteor showers
- Full screen or windowed mode
- Perspective projection
- Fisheye projection
- Stereographic projection
- Spherical mirror projection
- True Type font rendering
- Frames per second display
- Frame rate limiter
- Gravity labels for use in a dome
- Light pollution simulation loosely callibrated to the Bortle Dark Sky Scale
- Eye adaptation simulation

Localization :
- Sky culture: Western, Chinese, ancient Egyptian, Polynesian
- Sky localization
- Application localization

Scripting :
- Script input window
- Script loading via text user interface