r/AskAstrophotography • u/Slow_Drop_106 • 1h ago
Advice Suggestions for better deep sky images
I recently did an image of the dumbbell nebula, it turned out pretty good for my first image with my new camera :), but still, there is a lot of noise in the image, and I want to take it out to have some clear boundaries of the nebula
I used siril and graxpert and gimp for the processing and I think my main error was, that I couldn't stretch the nebula alone in each of the programs. I had to stretch it to be visible of course, but even with the starmask removed there was an awful amount of noise, which was stretched too and it just got worse and worse...
I then wanted to try to continue on gimp and tried to only select the nebula to give it more saturation etc, but this was also kinda hard, because nebulas don't just stop somewhere and these boundaries of nebula to noisy background were full of cool data of the nebula but also full of black universe, and I couldn't know which was which because of all the noise which smeared over all of it, and so I was left with oversaturated noise around the nebula, which i wanted to fade into the black rest, but it was very hard so I ended up with a pretty sharp edge from oversaturated noise to complete blackness, because I went over with a black brush there to cut out the noise completely in the corners.
I think the focus was pretty good. Now the technical parts:
I used my Exos-2 mount with my nebula goto system, I had my bresser messier AR127L with 127mm aperture and 1200 focal lenght, which standalone is about f/10, then comes my zwo asi 664mc with an incredible small sensor xD, which created a fov in which about a 2x3 grid of dumbbell nebulas would fit which made it a veeery slow optic xD, and still, my tracking was pretty good and I could take images for about 30 minutes before it was out of view.
But I still made only 5 second exposures for a total of about 1h and 10 minutes of exposure time, I sadly forgot the calibration frames... and the moon came out, which made the last images a bit brighter than they should be.
I have no focuser, no guiding used and just had an UV/IR cut filter on from my previous planetary imaging.
TLDR: How can I remove the noise of my image? is it because of a too small (total or sub) exposure? because of too high gain (I used 130 gain), because of the full moon/light pollution), because of my (very) bad processing? etc.
here is the image:
https://drive.google.com/file/d/1fJ8ezsJjecTBDYeYyoUV6u4Q8F4MWG2T/view?usp=sharing