Software for image processing
An interesting list of open projects for astrophysics can be found in the Astrophysics Source Code Library.
Multiple capabilities software
Software able to do several things, generally registration and stacking at least.
Siril
Siril was meant to be Iris for Linux. The new version is coming out soon. It has been updated to work with GTK+-3.4.
GIMP astronomy plugins
Website. Arch Linux AUR package.
These plug-ins for Gimp intend to be useful for astronomical image processing. They implement all basic functions for astronomy image processing, for GIMP's 8-bit images.
Single capability software
Software developped for one main capability.
AstroFocuser
Focus Helper for Astrophotography
astrofocuser is a very simple tool written with Qt 4.5 to help star focusing in astrophotogaphy. This tool applies an FWHM by transparency on the background window.
AstroAviBrowser
AstroAviBrowser is a small tool for astronomy imaging capture/processing. With AstroAviBrowser, you may open a video file, select the good frames and save the new sequence in a new avi file. It also debayer your raw sequences.