That's a cool shot. What scope is this?
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Originally Posted by dylan_odonnell
Hi guys,
First post to non-beginner deep space section. I hope I'm not being presumptuous!
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Not at all. Actually I still don't understand why there is a beginner section. Some of the pics in there are way better than some of the shots in the deep sky forums anyway.
Quote:
Originally Posted by dylan_odonnell
An issue I'm having is that the field isn't focussed from edge to edge. If I focus on a star in the middle , one side is slightly off. It's focus, not alignment or field rotation because I can see the hollow stars in high res. Out of focus is left hand side on this image.
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Your field curvature seems a bit excessive. I reckon your camera spacing on the corrector plate is wrong.
Quote:
Originally Posted by dylan_odonnell
I believe this is because of the camera sag as the cables / weight of cam pull down so the chip isn't totally parallel to the optics. I have the adjustment ring between the QHY12 and the hyperstar lens to adjust for this but it has 3 screws so I'm not sure how to do this apart from twiddling for hours and checking on my imaging software the focus on one side, and then the other, and then back again. Surely this would take *forever* ! And then I'd lose the lot once I pack up for the night. Does anyone have any tips for this? If I can get it right, I'd probably leave the hyperstar / ccd / ota all connected for as long as I can before changing the filter so as not to throw it all out again.
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You can certainly collimate the hyperstar but that would be for field tilt. The issue here is a spacing issue IMHO. Try to move the camera out or in a bit and see if your field gets flatter. A couple of mm will go a long way. Then take it from there.