Siril is an astronomical image processing software for Linux. Dev here is stopped: as of 2013/02, Siril development has moved and is regaining activity here https://free-astro.org/index.php?title=Siril
Just 1st time used it for processing of Lovejoy photos -- great program! Final result on my twitter feed PyZahl.
Thanks for Siril, it's good!
Looks promising but... please!!! Add a manual... It will be highly appreciated!