StarTools was created to complement the many freely available stacking and pre-processing solutions with unique, state-of-the art post-processing functionality.
Many stacking solutions provide rudimentary post-processing functions as well. Please note that only pre-processing and stacking should be performed in these applications in order for StarTools' signal evolution Tracking to work and achieve optimal results; Tracking cannot track signal and noise propagation that happened in other applications. As such, please do not stretch, color calibrate, perform gradient removal, or perform any other operations beyond initial calibration in these applications.
ASTAP, the Astrometric STAcking Program, is an astrometric solver, stacker of images, and provides photometry and FITS viewing functionality. It is available for all platforms.
Siril is a feature-rich, free astronomical image processing suite with excellent pre-processing capabilities. It is available for all platforms.
DeepSkyStacker is Windows-only freeware software for astrophotographers, which aims to simplify all the pre-processing steps of deep sky images.
Regim makes some processing steps that are unique to astronomical images a bit easier. Regim is available for all platforms.
"Simple but powerful", is the core philosophy of this Windows-only application.
Fitswork is a windows image processing program, mainly designed for astronomic purposes.
The Color module allows for various ways to calibrate the image, including by star field, galaxy sampling and - unique to StarTools - the MaxRGB calibration view.
The module can also be used as swiss pocket knife for gamma correction, normalisation and channel luminance contribution remixing.
You can convert everything you see to a format you find convenient. Give it a try!