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Biggest visual OTA for TAL-1M pier mount?

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#1 Jay_Bird


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Posted 07 May 2009 - 07:14 PM

When I've seen various OTA specials coming and going I've wondered what people have used successfully on the venerable TAL-1M GEM. That mount has manual slow motion on both axes with an RA clutch and AC motor. With Dec tension set right, it can just be pushed around the sky. Mine is on a portable pier that gives over 4-2/3 foot (about 1.2 M) saddle height, too tall for easy kids use with a Newtonian OTA. It gets occasional use when an 80mm f/6 Nighthawk comes off the alt-az mount. The TAL GEM is a 'bird in the hand' sitting in the garage that I would use more for outreach with the right OTA.

What is the biggest OTA that folks have put on this for stable visual use? I would use minimalist approach with Quikfinder RDF and a 2-inch 'finder' eyepiece.

A C-6 might work, or a 102/10 refractor.

I was tempted by a 127/6.5 refractor deal but the mount and it's about 5-pound counterweight seemed less stable with a 16 pound dummy load, even though it handles the 8-pound 80mm OTA very well. I'm guessing a realistic weight limit is in between, maybe at 12 pounds, plus or minus a little depending on the moment from tube length.

Has anyone used the 12 pound 120mm f/8.3 OTA on this?

Or the 120 ST f/5?

Any other options at f/10 or less, about 12 pounds or less, and 100mm or bigger aperture among achromat OTAs?


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