I am a total newbie regarding the processing of astrophotographs.
I have a question regarding the possibility of using several copies of the same series of images for stacking. For instance, can you take only 3 or 4 exposures, then duplicate each of those exposures several times, and saving the duplicates with unique names, and then stack those images to increase the quality of Milky Way photos taken with a DSLR?
The reason for my asking is I took several photographs, each with exposure times of 30 seconds of the night sky the evening of July 30-31, in order to attempt capturing meteors.
My setup was a Canon EOS 5D MKIII and a Contax Zeiss 16mm f/2.8 full-frame fisheye lens that was mounted on a Vixen Polarie star tracker. I made exposures at varying ISOs, ranging from 800-4000, and I shot at apertures either at 2.8 or 4.0. I did not make any exposures other than the ones that were of the night sky. The photos taken at ISO 800 are, of course, less noisy and I thought that a simple way to improve my images would be to combine a bunch of copies of the same photographs. I do not know enough about this, and I will be spending a lot of time viewing YouTube tutorials to help me figure out what I am doing.
Thank you in advance for your help!
Noise (except hot pixels) tends to be random so if you take multiple shots of the same scene and combine them you effectively reduce the noise. Some cameras work this way with long exposures.
The way to blend them is if you took five images of the same scene, open then as layers in a program. Then set each of the top four layers opacity to 20% and the bottom layer to 100%. This will reduce the noise really nice. If using ten images you would set to 10% opacity. Three images would see the layers set to 33% opacity.
Stacking is indeed not the correct operation for what you need, working with layers would be better. Stacking expects all images to have similar histograms.
Duplicating images is not needed, just weighting differently based on ISO value.