[bogert]

Hello~
I use an Astro-tech 72ED telescope prime focus for my birding photography. The results are fantastic, perfect detail (when I get the focus right).
But I was wondering if I could get the same great results using eye-piece projection? I have a number of eye-pieces for normal astronomy observing. Before I buy the adapter for eye-piece projection I thought I'd see other peoples results.
Would using 2" eyepieces with a 2" adapter be better and eliminate vignetting? Or would 1 1/4" eye-pieces be okay?
Thanks for any help.
Chris

[Paul Corfield]

I've tried this with a lot of eyepieces and never got very good results. You need an eyepiece that will project a parallel image so that it falls flat as possible on the ccd. Most eyepieces project a conical image and so you get quite bluured images away from the center. You can get around this by moving the eyepiece further from the camera so that only the good part projects onto the ccd. The magnification increase from doing this is usually so great the it's unusable. My best results came from using good quality orthoscopic eyepieces as they project a fairly flat image. Some results I posted here.

http://www.birdforum.net/showthread....ght=projection

I mounted my eyepieces inside a macro tube rather than buying anything special for the job.

Paul.

[bogert]

Thanks for the info.

[alphan]

I did tried using EP's between the focuser and camera without any other lenses but are not happy with result. A good quality EP may produce better IQ but costly. Telenegative are cheap yet produce better results.