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Old 01-10-2017, 02:56 PM
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Visionary (David)
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Barlow, Powermate advice

I have an excellent range of Ep's I really have no need for the added magnification Barlows & Powermates offer within my optical Astro endeavors. I believe there is a need within my photographic gear for a Powermate x4.
There is a marked difference in price between the TeleVue 2" Powermate and the 1.25 Powermate. Given that my current widefield camera is APS in size and at some time I will upgrade to a full-size sensor. Is it worth my while spending the extra $200 or so for a 2" Powermate, or in your considered opinion would a 1.25 be fine?
David
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Old 01-10-2017, 03:25 PM
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Merlin66 (Ken)
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David,
I've had, and used all the TV Powermates.
Note that the 1.25" sizes are x2.5 and x5; the 2" are x2 and x4.
You'll also probably need the special T thread adaptor for the Powermate to better fit your camera.
What exactly do you have in mind (target object wise) that makes you think of a PM?
I regularly use the x2.5 PM to get an f ratio around f22 for solar imaging but this uses an ASI 174 fast frame camera.....(I also need to add a T2 tilter to suppress newton rings)
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Old 01-10-2017, 04:46 PM
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Visionary (David)
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I am aiming for some basic Video Astronomy, planetary. Is anything gained by using a 2" for this application? It would be great to have some up-close high def of Jupiter and Saturn.
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Old 01-10-2017, 05:34 PM
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Merlin66 (Ken)
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David,
The optimum f ratio for detailed planetary/ solar is from f25 to f30.
The PM/ barlow should bring you close to these numbers.
Nothing to be gained from 2” fittings, the target image is so low.
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Old 01-10-2017, 08:30 PM
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Visionary (David)
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Quote:
Originally Posted by Merlin66 View Post
David,
The optimum f ratio for detailed planetary/ solar is from f25 to f30.
The PM/ barlow should bring you close to these numbers.
Nothing to be gained from 2” fittings, the target image is so low.
Cheers!
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