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Top five longest back focus refractors ??
Need some help here folks.
Always wanted to by a refractor but have been reluctant due to the back focus problems that can occur when trying to add bits and pieces. I would particularly like to use an ONAG to guide through the scope with as I already have one so I'm looking at about 100-110mm of back focus needed.
What I would like to do is use my QHY9M (22.5mm diagonal) to LRGB image 1-3 degrees of view if possible but I'm not sure what the focal length would be needed. The cost needs to be less than $2k if possible. I know there's some really nice Taks out there that would do the job but they are way over my budget. Size? Well I guess 102mm would be the minimum but 80mm can do some very nice images as well.
so the question is...
What are the top five longest back focus short F/L refractors that could fit my requirements?
Cheers
Stephen
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