The satpass script provides satellite visibility predictions, given the position of the observer and the NORAD element sets for the desired satellites. It can acquire the NORAD element sets directly from any site supported by Astro::SpaceTrack. It can acquire the observer's latitude and longitude from http://geocoder.us/, look up star positions in the SIMBAD catalog, and more.
Aciqra is a night sky simulator to show the sky and celestial objects. It uses the highly precise Aloac program to calculate highly accurate positions for planets, stars, comets, and everything else in the sky for thousands of years into the future. It can load a variety of catalogs and even custom ones with a bit of extension.
TerraJ is a Java port of fractal terrain and simulated solar system generation programs. The porting has included extensive refactoring, the creation of a documented API to enable reuse of parts in other programs, and extensions such as new Swing user interfaces. Full javadoc for the classes in the project is available.
ImageJ is an image processing program inspired by NIH Image for the Macintosh. It can display, edit, analyze, process, save, and print 8-bit, 16-bit, and 32-bit images. There are modules for biology, astronomy, nuclear medicine, physics, and more. If you can take a picture of something, whether with a microscope, a telescope, an oscilloscope, an xray machine, or a scanner, then this program will let you enhance, manipulate, and measure the results.
Gregorian calendar 1582 is a small Python script to generate calendars for any year in the history greater or equal to one. The output format is the same as the Unix "cal" command. However, it supposes the Gregorian Reformation took place on October 4th, 1582, in contrast to the cal, which supposes the reformation took place on September 3rd, 1752.
BOTEC is a simple but useful calculator that assists with astrophysical, orbital mechanics, and space navigation calculations. It is a "back-of-the-envelope calculator" rather than an industrial-strength calculator, although this may change in the future. It is primarily intended for people familiar with physics and Python, and as such is unlikely to be useful to the average end user. It includes solar system data, and all values are strictly in SI units.