[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.

[Free - MSDOS, dosemu] Program to analyse irregularly spaced time series - variable star light curves.

[commercial - Win95/98/NT] Scientific image processing and analysis software.

Auriga Imaging's program RegiStar automatically registers (aligns) astrophotos -- no user intervention required.

[commercial - DOS, Win3.1] CCD image processing software for amateur astronomers. Handles most file and camera formats. Allows tricolor imaging and 'track-and-stack as well'.

[open source - Unix, and VMS] A software package for interactive (and, optionally, batch) calibration and editing of radio interferometric data and for the calibration, construction, display and analysis of astronomical images made from those data using Fourier synthesis methods.

Picture Window is a popular tool among serious amateur astrophotographers. By Digital Light & Color.

Registax is a freeware tool that registers, stacks and processes image sequences. The program accepts either BMP's or AVI-files as input and will save the results as BMP or FITS.

[commercial, demo available - Win95/98] Main image processing features: unsharp mask, maximum entropy and Lucy-Richardson deconvolution, multilayer with auto-align, median, mosaic, RGB, LRGB images.

[commercial, demo available - Win95/98/NT/2000] Image processing and CCD camera control software for astronomical imaging. Supports Apogee, Celestron, FLI, HiSIS, Meade, SBIG, and Starlight Xpress CCD cameras; video cameras, autoguiders, and filter wheels. ASCOM compliant.