Re: ATM Diagnal and a Fast Mirror

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

Byron, one thing that you may want to consider with the whole diagonal thing
is to use a sliding focuser and carry the secondary on that slider.  The
focuser slides up and down the tube or the scope rather than moving in and
out from the side of the tube.  This will allow for a smaller secondary as
the eyepiece can be real close to the edge of the tube and thus not need as
big a secondary to be useful.
Another thing is to allow for some vignetting for the larger EPs that you
plan on using. A 25% obsruction is only a half magnitude of llight loss and
that isn't that much in reality.  Besides, the edge views are always going
to be poorer than the central view.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net