Tilt / collimation issues

[thomasv]

I have an ASI1600 hooked to a Canon 300 L lens via a filter drawer unit and an EOStoCCD adapter and been testing it the other night. Getting some not perfect star shapes near the corners, so I plugged the subs into CCD inspector and below are the results I'm getting. My question is what do these graphs exactly mean, should they be believed? How is it possible to have such an abrupt degradation in only one of the corners as indicated by the red area?

Thanks for any suggestions, I also attach a jpeg of the stacked subs and the camera-lens assembly.

 

[Fellside]

Hi Thomas,

Are all the components screwed together? Have you any way of adjusting the tilt. If possible try turning on component of the imaging train by ninety degrees. That might narrow down which part is causing the problem. Maybe the filter isn't seated in the draw correctly.

I have been using Maxselector recently and have found is works quiet well. As with all these programs they can get a little confused when you get close to a perfect setup.

Graham

[thomasv]

Thanks for the tips Graham, yes the assembly is all screwed together, but I've no provision for adjusting the tilt. I might try to come up with a way to fix both the lens and the camera to a dovetail bar, so that there are no stresses between the two due to weight.

I'll look into using Maxselector, thanks.