Help, strange shadows on my photos

Hello,
Are you using flat frames?

No, I have not used flats because I just wanted to try the camera to see how it works but the shape of the circles is very strange
At first glance, in the filters I don't see stains and the mirrors are clean. I will look at the shots of each filter separately in case there is something that escapes me. It gives the impression that it is like the reflection of "something"

.

This is simply caused by the absence of flat frames. Further more, I guess you took this photo under a bright moon.

Tian Li

Major vignetting and dust on sensor. Calibrate your image with darks, flats and biases.
your backfocus optical train may be off creating maximum vignetting?
CS

Thank you all.
I will wait a few good days and I will spend more time. I will do the flats, darks and bias to see the resultI thought it was something different because of the shape of donuts. On the weekend I will revisit the equipment and the photos with different filters.

It looks like you have some dust bunnies on your optics , flats should remove them, properly done, it also looks like there is some vignetting going on there, not sure flats will correct that much vignetting. Good luck, shawn

Hi Shawn,
thank you very much for your advice, I am waiting for the rain to stop, so that I can do the flats.
The vignette that is seen in the photo is very exaggerated because I have raised the contrast so that the spots look better.
In the lights it shows very little and with the background calibration it disappears almost completely.
I have a lot of work for the weekend  !!
Clear skies

Good luck, I'm sure you can easily calibrate out those dust bunnies with good flats! Clear skies hopefully!

Thank you very much for the encouragement.
I'm looking forward to changing the weather so I can take out the telescope. Before I had problems with  the spots on the sensor of the Canon but it was different that is why I found the shapes very strange.
I expected some spots but not with those shapes.
Clear skies

Except for probably the small one they are not dust bunnies, they are reflections. One can see the struts of the secondary mirror in the lower one and also faintly in the other ones. That´s also the reason why most of them are nearly perfectly round.  I thought that Mak-Newtons don´t have these struts and the secondary mirror is fastened to the lens/plate but your stars also have diffraction spikes which are orientated in the same way they are in the reflections.

Usually these reflections occur when light is reflected back into the system by the cover glass of the sensor. And is then reflected back to the sensor either from a filter or in some cases by the correction plates of SCTs, so theoretically also by a lens of a Mak. A theoretical option might also be from the filter back to the plate and back again. I´d check the filter option first and think about the Mak lens later (or try a different cam if you have the opportunity). I suppose you used a luminance filter? That there are so many reflections is strange however. And I´d also expect them to be near bright stars.

An astrocolleague is currently fighting his reflection problem, looks like this: https://astrob.in/wolx6l/0/

Flats won´t take care of reflections under the assumption that stars cause them (or another light source that is inherent to the specific subs). Flat light shouldn´t produce these reflections so one can´t cancel them out in the subs.