Looks like something on the sensor

burke

Has anyone seen this sort of thing on a sensor before? [See images] Its a zwo 224. I thought it was a dust mote or a lens flare but the images I attached are separate times, locations and circumstances. I purchased a sensor cleaning kit [see below] and used it a couple times with no effect. I'm posting an old allsky image. Also an image with the artifact still there after a cleaning. Also after cleaning, the circle moved when I moved the camera ... a reflection would not do this correct? Finally, an image of Saturn with the spot/circle. In a later capture of Saturn, I had to move the it around to avoid the circle.
I think it may have happened after the front plate unscrewed after using it as guide camera and attaching it directly to the guidescope. https://www.amazon.ca/dp/B093MPNWJT?psc=1![

Tech@ZWO

burke It looks like the reflection halo in the imaging train of the bright lights.
You can do these test:
1 connect the fisheye lens, and use a bright light to point at the lens, then move it to see if the halos change the position, if it moves which means it is the reflection.
2 Change the optical accessories in the imaging train in turn to rule out the problem, you also can remove the protective window on the camera to see if there is any differents.

Corsair

If you take calibration frames - Bias and/or Dark Flats, Dark, Flats - does it show up?

If you use calibration frames does it go away?

What telescope are you using for each of the photos? Could it be from the telescope? E.g. the corrector plate of an SCT?

Can you post a photo of the lens of your camera?

burke

Corsair . I only use it for guiding and planetary. Two images were using the fisheye and the Saturn with my C8.

At this point I'm beginning to suspect that if its anything other than lens flare, but to be sure and since its so inexpensive, I have ordered a new protective glass window.

If the problem persists, I will follow up with an image.

Thanks!

burke

Tech@ZWO Thank you. I have ordered a new glass window just to be sure.