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Old 07-01-2018, 09:47 AM
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astro744 is offline
Join Date: Apr 2007
Posts: 1,132
Are you intending on using a Paracorr at any stage (would be nice with your 'scope and 31mm Nagler)? If so you will need extra in-travel.

I just looked at the Moon with my 6" f5.5 Newtonian and 31mm Nagler with and without a Paracorr, (last Type 1 version with tuneable top and white index marks before Type 2 introduced).

With the Paracorr I had to move focus inward an extra 6 - 7 mm approx.

Note there is a note on the Tele Vue web site stating that the 1.15x magnifying factor was introduced to push out focus but this should not be taken as to push out past the position with no Paracorr but rather push out from a reference position of a Paracorr with no magnifying factor. This is to better allow usage of the Paracorr with most telescopes without modification. The 1.15x factor also flattens the field a little.

Find where your focal plane is and then you'll know what you need to do.
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