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. My 1 1/4 inch diagonal has standard filter threads on the front input opening. My barlow is just a small lense assembly tied to an extension tube with standard filter threads. 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. The spacing and thus the magnification at the eyepiece are the same as through the extention tube. DT --- Canopus56 <canopus56@yahoo.com> wrote:
I am considering adding a camera support bar to my 10" EQ 1120mm fl Newt for long focal length projection magnification. Although I have a simple design figured out, I was wondering what if one had done something similar and had any experience based tips or other suggestions. Basically, the a right-angle is inserted in the focuser, sending the optical path back to the rear of the scope. Then a barlow is used for negative projection, up to 300mm to 400mm long. This is intended to be used for projecting longer focal lenghts during astrophotography than what can be had by simply projecting "up" the axis of the focuser. - Canopus56 (Kurt)
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