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I think the OAG prism is the problem. The prism is extended quite a way into the optical path. Also, the bottom edge of the prism is not quite parallel to the long edge of the chip. It was rotated 5 degrees or so which would extend the corner of the prism on one side even further into the optical train. I’ve adjusted both and will check it out when I get clear skies again.
On Sep 4, 2021, at 12:06 PM, Wayne Hixson via groups.io <wayneh9026@...> wrote:
Thanks Roland - I’ll bet it’s the OAG prism. I’ll take a look.
On Sep 4, 2021, at 11:48 AM, Roland Christen via groups.io <chris1011@...> wrote:
These kind of reflections always come from some part very close to the focal plane. They cannot originate further up towards the objective lens. Since they are straight lines, they probably originate from some straight part near the chip. I have seen something similar coming from the bottom of an off-axis prism that was refracting (not reflecting) a bright star into the focal plane (similar to diffraction from a Newtonian spider). If not that, then are you using square filters by any chance?
Remove the camera body and look up into the optical train and look down into the camera. Do you see any linear (straight line) obstructions at the edges?
From: Wayne Hixson via groups.io <wayneh9026@...>
Sent: Sat, Sep 4, 2021 1:06 pm
Subject: Re: [ap-gto] Strange Artifacts -
Hi Robert, I should have mentioned these appear on almost all the subs, so it doesn’t appear to be more random events like meteors. I suspect it’s reflections somewhere.