[jumpjack]

Non so come si chiamino in gergo i software "uniformatori di luminosità", comunque eccone un paio:

Enblend: https://enblend.sourceforge.net/index.htm
Multiblend: https://horman.net/multiblend/

Image stackers:

http://www.astronomie.be/registax/index.html

http://www.photoacute.com/studio/index.html