50mm F16

I think this is the slowest scope I’ve ever owned. My slowest one was GOTO 80mm/F15 around 40 years ago.

800mm focal length. Yes, physically very long too. This is Japanese-made achromat lens. I was told by a Japanese friend it was still polished in Japan and good production quality. So I got it for solar use for experimenting. Temporarily I just clamped by a ring to hold the objective and looked at the moon last night. It’s clean and good contrast. Nothing disappointed. The result was what I’m willing to step forward to the next. If it is good enough for the sun, I will go ahead making the special adapter for BORG Series 80 tubes and filter thread in front. Now I’m just waiting for the tentative adapter from machine shop just for experimenting purpose. Once it will be up, I will test this along with 600mm one. My only concern is the image contrast for the bright target like the sun. AR coating is not basically designed for that to minimize the production cost.

 

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~ by tedishikawa on February 15, 2016.

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