Seestar S50: light and dark bands on images

oRX2hR4h

I noticed that my images straight out of the Seestar app display a pattern of light and dark bands (see example below where I increased brightness and contrast in order to highlight the issue). What could be the cause of this?

oRX2hR4h

Same issue described by another user in the following thread: https://bbs.zwoastro.com/d/17107-weird-artifacts-always-appear-on-my-image/10

Is this common among S50 units?

x4q8nHzc

As mentioned it may be light leaks. Making sure light is prevented from falling onto the unit via dew shield or similar might alleviate it.

oRX2hR4h

I have tried a 40 cm lightshield and it does help a bit but the banding always appears. The fact that the bands are fixed in position irrespectively of the direction the scope points to, speaks against a leak, reflection or stray light explanation. It appears to be an undesired response of the sensor to diffuse light.

The issue can be reproduced if you illuminate the Seestar under angle with a diffuse light source (in a darkened room in order to control the amount of light). Under totally dark conditions the sensor does not show any sign of large scale banding. If illuminated from the sides, you get the vertical banding. When illuminated from top/bottom, the horizontal banding shows up. Below are the screenshots from the experiment.

Brille

This is a remarkable study with an interesting result. I, like others, have irregular vertical stripes like this in the picture, which I can now explain. I'm wondering whether it might make sense to put the Seestar in an opaque black bag or something like that. We would have to investigate where the light is coming from. Is it only through the housing or perhaps also through the slits in the side wall?

oRX2hR4h

Brille just to clarify: the light in the aforementioned experiment is hitting the objective, i.e. it is not an issue of a light leak through the housing etc. I just tried to simulate the impact of light pollution. The question is why does the Seestar produce a fixed banded pattern instead of a more or less arbitrary gradient.

Brille

How did you rule out the possibility that the stray light is only entering through the lens, but not anywhere on the housing? After all, a 40cm long tube should reasonably ensure that no stray light reaches the sensor. It is also really strange that there are sharply defined bands.

oRX2hR4h

Brille ruling out a light leak through the housing is very easy: just cover the objective and immediately no signal is being detected no matter how much you illuminate the Seestar S50. As said, the fixed pattern seems to be an undesired response of the sensor to diffuse background light (malfunction?). Since the appearance of the banding has been reported by many users maybe Support@Seestar, Tech@ZWO or AstroImg@ZWO could provide some insights on this issue.

Support@Seestar

oRX2hR4h Please don't worry, our team is discussing the situation today and I will get back to you when I hear something.

NavierIsStoked

Has there been any further information on this? My images seem to suffer the same problem. Here is a stacked image of M3 (Globular star cluster). 857 sub, 10 second exposure on each.

oRX2hR4h

NavierIsStoked yes, see here