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saxon FCD100 127 focuser
Hi all, I'm mucking about with a saxon FCD100 127 APO for my job. I've got a question for the brains trust, because I'm not sure I understand the geometry.
To focus on infinity with my little 20mm 1.25" test eyepiece and the diagonal, I needed one of the two 37.5mm spacers supplied with the scope. The focuser was racked out to about 26mm.
To focus on infinity with my DSLR (without the diagonal) I needed both spacers and even then the focuser was racked all the way out to 44mm.
I've attached two pictures showing both of these.
Perhaps I'm wrong here, but I can't see any application that would require no spacer to be in the train. A shorter (non-parfocal) focal length eyepiece might require racking in, but not by 20mm, right? Removing the diagonal and just going for the eyepiece would require more spacers, right?
Or am I completely wrong?
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