Frink is a calculating tool and programming language designed to help you in the real world. It tracks units of measurement throughout all calculations and ensures that answers are correct. It converts between systems of measurement, and has a huge library of physical data. It is both a simple calculator for quick calculations and a full-fledged programming language for large tasks. It draws high-quality graphics, handles conversions between time zones, currencies, and historical values of the U.S. dollar and the British pound, translates between several languages, does date/time math, and more.
Gpredict is a real time satellite tracking and orbit prediction program. Besides the general orbital data for satellites, gpredict can also calculate the footprint, visibility, doppler shift, signal loss, and signal delay for each satellite relative to one or more ground stations. The calculated data can be viewed in tables, on maps, or on polar graphs.
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.
AstroAviBrowser is a small tool for astronomy imaging capture/processing. It allows you to open a video file, select the good frames, and save the new sequence in a new avi file using raw or lossless codecs. You may also de-bayer your frames and separate RGB plans. It's a kind of "AviRaw" for Linux.
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.
Astronomy for fun (education, science, whatever). Nightfall is an interactive application to simulate eclipsing binary stars, and to produce animated views, synthetic lightcurves and more. Takes into account the non-spherical shape of close binary stars, mutual reflection, and some other effects. Comes with documentation, on-line help, and lots of observational data of real binary stars. Supports the Gnome desktop, but doesn't require it.