Re: Reflections in Images


Roland Christen
 

There is one other remote possibility that you can check out with the camera removed. Look up the camera adapter tube past the baffle tube towards the secondary. Now place your eye at the edge of the camera adapter tube and look if you can see clear sky past the primary and secondary baffles. If you can see the sky directly past the baffles (would look like a thin crescent shape of sky), then it is possible for the light of a bright star to enter directly into the imaging train and cause an arc of light. If that's the case then you would need to make the secondary baffle somewhat larger to block this source of stray light.
 
This is most probably not the source of your stray light, but it would be good to check out.
 
Rolando
 
 

-----Original Message-----
From: 'Steven Reilly' sreilly24590@... [ap-gto]
To: ap-gto
Sent: Thu, Feb 4, 2016 2:29 pm
Subject: RE: [ap-gto] Re: Reflections in Images



If I’ve learned anything in this life it’s that I listen to 1, my wife, and 2, Roland. I took the camera off the telescope and turned on the FlatMan XL at full brightness. There appear to be some suspects but they are as far away as 7” which I find even less suspect as the arc appears to be finely focused making me think it’s very near the CCD chip itself. What few surface reflections I did see I covered with flocking paper. As the FW8 is part of the camera there is no removing the filter wheel itself, the camera came with this when new, but I could remove the filter carousel itself if needed. For now, it’s intact. I also flocked the STL camera adapter for the Pyxis which is as close as anything come to the camera/filter wheel. Of course it’s likely a few days before a clear night is expected so I’ll have to wait and see. And it will have to be tested on NGC3521 as this is the target that the past few imaging sessions have this problem. Other images taken the same night on different targets show none of this.
 
Thanks,
 
Steve
 
 
From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 2:09 PM
To: ap-gto@...
Subject: Re: [ap-gto] Re: Reflections in Images
 
 
It's no use showing the picture of the large parts of the scope (i.e. primary mirror, etc). That's not where the reflections are coming from.
REMOVE THE CAMERA (emphasis mine), now look up the small parts that are near the camera, ALL of them, not just the focuser. Take a picture up from the tail end with the scope aimed up at the bright sky - with all of the parts in place, only the camera removed.
 
Rolando
 
 
-----Original Message-----
From: 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Wed, Feb 3, 2016 1:04 pm
Subject: RE: [ap-gto] Re: Reflections in Images
 
Gotta run pick up the pup but I just uploaded new pictures of the imaging train and interior/exterior of the telescope. See http://www.astral-imaging.com/reflection.html and no, you don’t need to mention the dirt on the primary.
 
Steve
 
 
From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 1:21 PM
To: ap-gto@...
Subject: Re: [ap-gto] Re: Reflections in Images
 
 
Steve, did you already say if it was affecting all filters? 
 
Stuart
 
On Wed, Feb 3, 2016 at 1:16 PM, 'Joseph Zeglinski' J.Zeglinski@... [ap-gto] <ap-gto@...> wrote:
 
Steve,
 
    By chance, do you have an empty filter? If not, remove one filter, as a possible optical cause, and see if one or both problems go away.
 
Joe


 
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