Re: Re[2]: [ATM] Back Focal Distance design considerations

["Bob May" <bobmay@nethere.com>]

The corrector needs to be moved a little bit so that there is room to adjust
the focuser to where you want to have it for the focusing range.  You may
lose a little bit in the spot size but when you really look at it, the
difference will be very minimal.
The alternative is to make the scope so that the corrector goes inside the
focus tube and either is stationary (make the focus tube larger in diameter
to keep the FOV - you don't need to have the inside diameter of the tube
itself to be 2" in diameter!) or attach it to the focusing tube.
Bob May
bobmay@nethere.com
http://nav.to/bobmay
http://bobmay.astronomy.net

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