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Old 18-04-2013, 02:13 PM
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Nico13 (Ken)
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Question GSO RC 8" and DSLR question

Hi all,
Thinking about the above mentioned scope as an upgrade from my current SCT for use with my DSLR APSC size sensor and was just wondering if anyone was using a similar setup and if it suffered with any vignetting issues?

Thanks for any help in this area.
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Old 18-04-2013, 07:18 PM
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rmuhlack (Richard)
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Can't speak to the RC8, but I can tell you that there is little vignetting when using a APS size chip on a Vixen VC200L, even with the 0.71x reducer. A flat (unstretched) from last night is attached. The VC200L includes a triplet flat field corrector as standard, so even without the reducer the field is fully corrected out to a 44mm image circle (ie a "full frame" DSLR).

A VC200L is a lot more expensive than a RC8 though so that is obviously a consideration. The focuser is from all accounts a zillion times better than the GSO though (not hard to believe if my GSO newts are anything to go by), so no need to upgrade there.
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Old 18-04-2013, 08:21 PM
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Nico13 (Ken)
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Thanks Richard,
That's not too bad at all, wouldn't take much to flatten that out.
The VC200L was definitely another scope of interest but yes the price is also a consideration so still looking at this stage.
Oh by the way just loved the deep M104 post you put up, nice work.
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Old 19-04-2013, 05:47 PM
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NO problem whatsoever Ken. I used a D40 with my RC8 for over a year. Below are a few of the images I did with that setup. All taken from 2008 to 2009. No vignetting present in those images. Some vignetting in the subs but using flats got rid of those problems.

http://paulhaese.net/trifidcloseup.html

http://paulhaese.net/NGC5128closeup.html

http://paulhaese.net/NGC4945.html
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Old 19-04-2013, 08:46 PM
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Nico13 (Ken)
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Thanks Paul,
I noticed on the image links that you had been using a Tak flattener, I was under a miss comprehension that the the RC 8" was a flat field scope and not requiring a flattener.
Nice shots by the way as that's what I'm hopping to achieve with an upgrade.
How flat are the the images without the flattener?
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Old 20-04-2013, 07:48 AM
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Hi Ken,

RC scopes are not flat fielded in their native form. They do however correct for coma. The field on an RC8 has a bit of field curvature and you could get away without having a flattener if you crop the image. This might limit the targets you image though.
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