Chuck, I did shoot a couple of photos through the original Digistar lens. It was a 43 mm f2.8 160 degree FOV lens and covered a 5 inch circle. I put a 4X5 adapter on it and attached it to my Byers mount. I let it go unguided for about 30 minutes. I was using Ektachrome - probably ISO64(???) My recollection is that I didn't get much in the way of stars. I could barely see the Andromeda Galaxy. I also did not see much trailing either. I didn't look for trailing due to atmospheric refraction, so I am afraid your original question is unanswered here. It was fun to use a $25,000 (1980 dollars) large format fisheye lens though. Brent --- Chuck Hards <chuckhards@yahoo.com> wrote:
Has anyone (Rob? Patrick?) tried tracking fairly long-exposures with a "fisheye" lens? I'm wondering if, guiding on a star near the center of the field, if the edge stars trail because of differential atmospheric refraction? A few years ago I acquired a nice fisheye lens with a FOV darned near 90 degrees, and would like to try it on the sky when the weather warms up. Any meaningful input based on experience is welcome.
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