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New binos are here

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#1 tomhole

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Posted 07 May 2003 - 04:14 PM

The new to me Denk standards and 1 1/4" OCS came in yesterday. It was cloudy last night, but the moon is up in the daytime sky today so I did some playing around with the various barlows and powermates I have. The results are guesstimates, but very interesting. XT10, 1200mm f/4.7, 2x TV barlow, 2.5x and 5x powermates.

With a set of 25mm, 55 deg AFOV plossls and the OCS, the TFOV looks to be about 55 arcseconds as advertised (1.2x).

With the 2x TV barlow alone (no OCS parts) it looks to be about 16 arcseconds. About 4x, makes sense.

The powermates were interesting. The 2.5x powermate with no OCS parts resulted in about 26 arcseconds, which is about 2.5x. Same with the 5x powermate and no OCS parts, about 13 arcseconds or 5x. I guess the powermates are an OCS. I know that Harry has mentioned this before, but it's interesting.

So, with no OCS parts, I get 2.5x, 4x and 5x with my magnifiers.

I also tried putting the barlows and powermates in front of the OCS configured for 1.2x mode and they all came to focus and gave the expected magnifications for 2x1.2, 2.5x1.2 and 5x1.2. This makes for a very long optical path and a heavy piece of kit at the end of a long tube.

There are so many OCS, barlow, powermate combinations to try it is mind boggling. I wish there were a quick way to swap the OCS on and off. This would let me use my powermates and barlow as higher power OCS's and easily get a wide range of powers. With a pair of 24 Pans, I could get 60, 125, 200 and 250x. 2 premium ep's and a whole night worth of fun.

I would suspect that the 2" powermates behave the same. Maybe the dream setup is the 2" OCS and the 2x and 4x 2" Powermates and a setup that allows swapping them quickly. Hmmm, maybe I'll give Russ a call.

Clear skies,

Tom

Clear skies,

Tom




#2 tomhole

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Posted 08 May 2003 - 02:10 PM

Well, I have a path to a solution. I bought the 2"/1.3x OCA from Harry Siebert. It does exactly what I needed. Allows me to swap the OCA and powermates without doing any screwing and unscrewing. I'm pretty tickled pink about that. I'll let everyone know how it works out. Now, if it would just stop raining here in MD, I could get out and actually try these things out. Nothing worse for the wallet than cloudy nights. :bawling:

Clear skies,

Tom


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