From: Milton Aupperle <maupperl@gmail.com>
Date: October 14, 2015 8:46:57 AM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] First ever AstroIIDC screen capture with a Chiefspiegler
Hi Jim;
Thanks so much for the notes and advice.
Can you clarify how much peripheral coma there would be say over a 1" sensor?
From briefly looking at the design last night, I also wondered if one could use smaller diameter lenses behind the second mirror rather than in front of it - but I'm sure if that was possible, it would have been done by now.
The dream scope would be in the 14 to 16" range and at F8, at a permanent dark site in rural Saskatchewan.
All that extra light captured with no obstruction, improved contrast improved resolution would be amazing.
Talk to you later..
Milton Aupperle
On 2015-10-14, at 6:17 AM, jim_chung@sunshine.net [Astro_IIDC] wrote:
Hi Milton,
The beauty of the Ed Jones Chiefspiegler design is that you can indeed buy the optical components needed, within reason. You are probably limited to about a 10" f/8-f/10 scope, slower & smaller diameter the better because the required planoconvex and planoconcave lenses generally top out at 50 mm diameter from commercial sources.
I have a 10" f/8 primary, a 3.5" diameter circular flat, and 50mm planoconvex/planoconcave lenses 600mm focal length.
If you want to build a bigger Chief, larger planoconvex lenses can be found (Ross Optical) but the planoconcave are impossible to source. Have Ed Jones make one for you and it will also be optimized for perfect color correction.
If you adjust everything right you will get a perfect star test with no coma or astigmatism on axis (peripheral coma from the primary mirror will still be present).
regards,
Jim
Milton J. Aupperle
206 - 6414 Travois Place NW
Calgary Alberta T2K 3T2
Phone: 403-453-1624
http://www3.telus.net/maupperl