[open source - Unix, OpenVMS] A general-purpose software system for the reduction and analysis of astronomical data. IRAF is written and supported by the IRAF programming group at the National Optical Astronomy Observatories (NOAO) in Tucson, Arizona.
http://iraf.noao.edu/
[open source - Linux/Unix, VAX/VMS/OpenVMS] General tools for image processing and data reduction with emphasis on astronomical applications including stellar and surface photometry, image sharpening and decomposition, as well as imaging and special reduction packages for ESO instrumentation.
http://www.eso.org/esomidas/
[commercial - Win95/98/NT] Scientific image processing and analysis software.
http://www.axres.com/
Review of the solar system simulator (by Spacetech) for RISC OS workstations.
http://www.harmsy.freeuk.com/orrer.html
[open source - Linux/Unix] Interactive program for computing synthetic lightcurves and generating animated views and best-fit models of eclipsing binary stars.
http://www.hs.uni-hamburg.de/DE/Ins/Per/Wichmann/Nightfall.html
[shareware MS-W] Sunlight clock with world times and sun and moon positions and coverage.
http://www.geoclock.com/
[commercial, demo available -- Win95/98/NT] Includes calendars required by historians of astronomy and general historians. Many details are provided for Indian and Jewish calendars and much besides. There is also a display of positions of the Sun, Moon and planets, effectively replacing Tuckerman's tables. A horoscope display, and details of lunar visibility, are calculated from modern parameters.
http://ourworld.compuserve.com/homepages/raymondm
Astronomical software on Linux.
http://bima.astro.umd.edu/nemo/linuxastro/