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Old 25-05-2019, 08:30 AM
Stefan Buda
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Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 823
Quote:
Originally Posted by Paul Haese View Post

I believe this problem is caused from the idea that the filters are within the casing of the camera and not in an external filter wheel.

So for example my GPU corrector is 55mm back focus. The Camera has a back focus with the mount I have of 50.17mm. If I subtract 1mm from 50.17 I end up with 49.17 and that subtracted away from the 55mm back focus is 5.83. This corresponds really well with the actual imaging for curvature.

Hope that helps.
Perfectly explained. I knew it had something to do with the way of looking at it.

Quote:
Originally Posted by Slawomir View Post
Paul explained it very well.

I have QSI 690 and increasing spacing between Riccardi reducer and the camera by 1mm to account for Astrodon filters gave the best results at f/4.5. I also tried decreasing the spacing by 1mm and star correction got significantly worse. Didn't see as much difference with both scenarios with a dedicated flattener at f/6.
Indeed.

Thanks everyone. Case closed.
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