Years ago I bought a refractor for $70 from a surplus store. As it turns out I got quite a deal. It is a Petzval APO design with a very large flat spot. The original focal plane had a 3x5 inch ground glass target. I was told that it might have been part of a boresight tool for a 16 inch naval cannon.
I cut down the end of the tube and installed a 2" focuser. I was very new at the hobby, but on one clear day I saw beautiful festoons on Jupiter. Sadly, I disassembled it to clean the lenses and did not mark lens positions. Now it has a rainbow fringe indicating it is out of alignment.
I need to know how to align this instrument. I do have a 5" 1/20 wave flat and can make most any tool I need. The objective is an air spaced doublet with about 1/2 inch between elements. The corrector has two elements spaced a 2 - 3 inches apart. The outer lens of this corrector is extreme. It has a 1 3/8 inch sagita. The focuser tube actually sits inside the lens when it is racked in. The spacers are metal rings and the lenses fit in machined ridges so it appears that the only alignment I can do is to rotate lenses and/or spacers. The lens pairs are each mounted in their own removable frame with spacers and threaded retaining rings.
Can anyone help me with instructions on how to align this OTA?
Thanks
Tom
I cut down the end of the tube and installed a 2" focuser. I was very new at the hobby, but on one clear day I saw beautiful festoons on Jupiter. Sadly, I disassembled it to clean the lenses and did not mark lens positions. Now it has a rainbow fringe indicating it is out of alignment.
I need to know how to align this instrument. I do have a 5" 1/20 wave flat and can make most any tool I need. The objective is an air spaced doublet with about 1/2 inch between elements. The corrector has two elements spaced a 2 - 3 inches apart. The outer lens of this corrector is extreme. It has a 1 3/8 inch sagita. The focuser tube actually sits inside the lens when it is racked in. The spacers are metal rings and the lenses fit in machined ridges so it appears that the only alignment I can do is to rotate lenses and/or spacers. The lens pairs are each mounted in their own removable frame with spacers and threaded retaining rings.
Can anyone help me with instructions on how to align this OTA?
Thanks
Tom
There are only 10 kinds of people who understand binary - those that do and those that don't
