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Earthwin optical path length ?

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#1 bilgebay

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Posted 08 May 2013 - 04:22 PM

I am trying to put together the necessary parts for using my Earthwin binos in my new C6 and C8 Edge scopes. Can anybody tell me the optical path length of the Eartwin binoviewers ? The distance I need is from the front dovetail to eyepiece focal plane.

Thanks

#2 GlennLeDrew

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Posted 08 May 2013 - 10:23 PM

If you have the BV, you can easily measure the optical path length yourself.

Install the BV in the daytime, and place a piece of tissue paper inside one of the barrels, up against the prism opening. Focus some object onto the paper; the target need not lie at infinity. Measure the distance from some convenient surface at the scope's back end. Remove the BV--but do not touch the primary mirror focus--and find the new focus position and measure the distance, using the same reference surface as before. The difference in distances is the optical path length required for the BV.

#3 bilgebay

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Posted 09 May 2013 - 12:50 AM

Thank you Glenn.

My problem is I have the bino but it is in my obs which is 500 miles away from me right now :) Saturday I will be there but then it will be a bit late for ordering the stuff which needs to be in Wisconsin latest by next saturday for me to pick up during my stay there :(

Anyway, let's see if any friends here or Bill at Earthwin can give me this info earlier than Saturday. I've sent an email to Bill as well.

Best wishes

#4 Fred1

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Posted 09 May 2013 - 07:17 AM

Hi Sedat, call Bill or John at EarthWin. In the meantime, to the best of my recollection, I think Bill told me some time ago that the path was 118mm... or 119mm... or 115mm. I recall that it was at least 10mm shorter than my TV Bino Vue which is 129mm. I'm sorry that I can't be more clear.

#5 bilgebay

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Posted 09 May 2013 - 07:30 AM

Thank you Fred. That's a great help.

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