Planets is a fun, interactive program for many-body gravity simulations. The emphasis is on play: it's easy to add in planets, zoom in and out, change the physical constants, save and load configurations, etc. It's designed to be easy enough for a kid to enjoy, but that hardly precludes adults.
PyNOVAS allows you to calculate the position and movement of the sun, moon, planets, and stars with great precision using Python. It is based on the NOVAS software used by United States Naval Office (USNO) to produce the 'Astronomical Almanac' and 'MICA'. Ephemerides are supplied by the Jet Propulsion Laboratory (JPL). You can use this software for Celestial Navigation, and also as a basis for controlling astronomical equipment.
Qastrocam is a capture program that can work with any video4linux device. Its main purpose is to do astrophotography. It can control a telescope to do guiding with the images received from the video device. It can also control the extended features of a webcam modified to do long exposure (several seconds) captures.
Qastrocam-g2 is a fork of the Qastrocam project, Webcam capture software for astronomy. This fork adds support for RGB24 (luminance only) and YUYV. It has better generic V4L support (lx mode and resizing). Settings backup has been added. There is better parallel and serial lx mode support. There are a number of other changes and additions.
Remote Telescope System (RTS2) is an integrated system for remote observatory control. It is designed to keep an observatory running, protect it from elements, take images, ensure that pointing is good, react to TOOs, keep track of what was done, send you data, and help you to do science. It picks targets from a database table, stores image meta-data in a database, processes images, and stores WCS coordinates in the database. An abstract device layer enables control of all possible combinations of mounts, CCDs, photometers, and roof and cupola controllers.
SAOImage DS9 is an astronomical imaging and data visualization application. DS9 supports FITS images and binary tables, multiple frame buffers, region manipulation, and many scale algorithms and colormaps. It provides for easy communication with external analysis tasks and is highly configurable and extensible. DS9 is a stand-alone application that requires no installation or support files. It supports advanced features such as multiple frame buffers, mosaic images, tiling, blinking, geometric markers, colormap manipulation, scaling, arbitrary zoom, rotation, pan, and a variety of coordinate systems.