Re: [ATM] Lens after diagonal?

["john sherman" <atm@mail.johnspics.com>]

Hi list,

Transfer lenses?

Shucks, I always thought the best way to minimize secondary size was to put a Barlow lens just in FRONT of the secondary. The Barlow does not increase the obstruction size. It does increase the F/# of the scope, so you can make a faster primary and keep the eyepiece closer to the ground, and have a smaller obstruction than the equivalent "normal" Newt.

Like, you could have a 36" F/3.5 primary with a 4" obstruction, and an efl of F/6..

And if you're really talented, maybe your Barlow could double as a coma-corrector.

Have fun!

John





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