--- daniel turner <outwest112@yahoo.com> wrote:
Kurt: The focal plane of the newt is right near the top of the fully racked in focuser. In order for the barlow to work properly, it needs to be upstream of the primary focal plane or down in the focuser. . . . So I often take the lense assembly and screw it on to the front of the diagonal and let the light path through the diagonal act as the extention tube.
Daniel, Thanks, that's a good trick that I hadn't considered. This week, I installed a Cray 2" low-profile focuser in order to get enough flexibility to be able to conveniently set the "A" distance between the negative barlow and the prime focal plane. I am projecting through a filter wheel and a flip-mirror onto either a Meade DSI or film camera. In some configurations, the optical train is a little long. It looks like it would be safer for the scope body, the focuser and the projection/astrophoto components to have an extra point of support other than just the focuser itself. - Canopus56(Kurt) __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com