QHY268 mono problem

[Mark Johnston (Mark Johnston)]

I'm not sure if this is the best forum for this but I recently bought a QHY268 mono camera and filter wheel. I'm using on a GSO RC10 which I've had for a few years and used with other cameras, Atik and ZWO 1600MM Pro. Straight out of the box I'm getting what seems to be a form of vignetting where the centre of the image is very bright as shown in the attached images. I hadn't seen this with other cameras on this scope. I'm surprised it's so noticeable as I saw another image on Cloudy nights taken with this camera with no flats or darks and it showed no such effect. I also tried the camera on my ED80 with similar results. I've checked for light leakage and ruled that out. I'm not using any reducers or flatteners in these tests. Any advice would be welcome.

Mark

[multiweb (Marc)]

Have you ruled out some fogging issues or reflections?

[Wilsil (Wilco)]

What size filters are you using?
I am using 2" filters on my ED80, a bit of overkill but future proof.

[Mark Johnston (Mark Johnston)]

Originally Posted by multiweb

Have you ruled out some fogging issues or reflections?

I've checked for fogging, couldn't see any. Reflections not so sure.

[Mark Johnston (Mark Johnston)]

Originally Posted by Wilsil

What size filters are you using?
I am using 2" filters on my ED80, a bit of overkill but future proof.

I get the effect without filters as well as with, so it isn't the filters.

[Startrek (Martin)]

Severe vignetting possibly a spacing issue in regards to focal length ?