It's just a Newtonian, Dion, but instead of deflecting the light path 90-degrees, it's reflected back down the optical axis at a shallower angle, coming to focus just outside the light path of the 70-inch aperture. Mike then uses a regular 2-inch star diagonal to bend the light 90-degrees for a more convenient viewing angle. Some people these days call them a "lowrider" variation. JMI has been selling a similar configuration for years on their largest scopes. This enables a lower viewing height and shorter ladder for the observer. The secondary is a flat mirror, no curve. On Mon, Oct 21, 2013 at 12:40 PM, Dion Davidson <diondavidson@yahoo.com>wrote:
Maybe a dumb question - but what is the optical design of the scope? I have never seen a reflector with the eyepiece back down near the mirror, pointed toward the sky. ref images: http://www.ksl.com/?sid=27301024&nid=460#1 Dion