Hello, I have a problem with spots appearing on my photos. I have an ASI 533 MC Pro Color, a 150/750 Newtonian telescope, and a coma corrector.
Thank you in advance.
20251117_222722_Light_M 45_300.0s_Bin1_20251117-222723_0002~2.jpg
20251118_024210_Light_IC 434_300.0s_Bin1_20251118-024208_0034~2.jpg
20251214_192814_Light_M 45_300.0s_Bin1_20251214-192814_0001~2.jpg
Are you shooting a proper calibration frames?
Here is the final photo with the calibration photos.
Could this be related to FLAT?
What I don't understand is that these two photos were taken on the same night without touching anything, and the stains don't overlap.
20251117_222722_Light_M 45_300.0s_Bin1_20251117-222723_0002~2.jpg
20251118_024210_Light_IC 434_300.0s_Bin1_20251118-024208_0034~2.jpg
Yes, how are you taking your calibration frames and what do your flat frames look like?
If your calibration is good then, considering the large number if bright stars in both of these fields, I would tend towards that as well. It would be easy to retouch these out.
So it's not a problem?
Wandrille VINCENT · Dec 17, 2025, 07:53 PM
So it's not a problem?
You should be able to clone stamp/blemish blast out those issues on the starless version of your image. Looking at more of your photo examples, I also think you’re getting some kind of reflection from the bright stars. Those two targets are often tough when it comes to reflections due to the brightness of the stars and number of them.
Here is the final photo of the horse's head. It's still very intriguing.
It’s a reflection from the sensor glass to the glass of the coma corrector and back to the sensor.
Notice how you can draw a line through the centre of the frame from a bright star and you will land on the aberration, with the star and the aberration an equal distance from the centre point?
I had this with the TS Optics GPU corrector and my 700D. Almost cured with the better AR glass on the 2600NS which I have now but still there on extremely bright stars
Any filter in the optical path?
Had this king of artefact on a RC8 with brilliant stars as Alnitak . I upgraded the UV/IR filter to higher standard and the problem was solved
Non, simplement un correcteur de coma.