Gimp in astrophotography - fixing shapes and colors of stars скачать в хорошем качестве

Gimp in astrophotography - fixing shapes and colors of stars

In this video I show a GIMP-based method for fixing colors and shapes of stars, mostly in the corners of the image. As an example I use a stack of M31 galaxy, made by Sebastianus, one of the users of the Polish forum Astropolis. Because of the chromatic aberration, the red color is focused in different location than the green and the blue colors, which results in multicolored, elongated stars. To fix this, after initial stretch in Siril and separation of stars in Starnet, I split the image of stars into three components, R, G and B, located in three separate layers, and change the size of the R layer, so the location of the R stars better matches the location of the stars in G and B. After this I additionaly run an equivalent of Hasta La Vista, Green! process, known from Photoshop, to remove the excess green in centers of the stars. To remove purple fringes around stars, I invert colors of the image, and run the equivalent of HLVG once again (after invertion, purple becomes green, and HLVG removes green :) ). Then I invert colors once again, to come back to normal colors, and do some more tweaking with the saturation of the stars and removing gradient from the image of the galaxy. Enjoy! :)