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Binoviewing with just one reticle eyepiece?

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#1 R Botero

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Posted 13 August 2013 - 09:16 AM

Hello All

I enjoy looking at doubles with my Mark IV binoviewers and a pair of Baader Mark III zooms. I estimate positions and separation from the known field of view and some reference pairs.

Has anyone tried using a single reticle eyepiece, accompanied by a matching non-reticle one, to trick the brain into "measuring" with both eyes? Could this be done?

I don't want to go down the filar micrometre route yet for measuring doubles as I love my binoviewers!

Thanks for your input.

Roberto

#2 TomCorbett

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Posted 13 August 2013 - 10:23 AM

Interesting question. And how about an illuminated reticle eyepiece (double cross hairs)in a binoviewer to assist in locating alignment stars for GOTO setups?

#3 GlennLeDrew

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Posted 13 August 2013 - 12:36 PM

As for alignment purposes with BV installed, one needs only a single eyepiece, and so even a reticle eyepiece can be completely mismatched in focal length and still work just fine.

Now to the original question. Yes. If the focal lengths match to within a couple percent or several percent, such use is fine. The apparent field of view doesn't need to be the same, as you're concentrating on the central part of the field for the most part with doubles. Indeed, a single reticle is probably best anyway, considering the potential difficulty of having two aligned both in plane and rotation, and with the images.

#4 R Botero

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Posted 14 August 2013 - 04:18 AM

Hi Glenn

Many thanks - that's interesting. The Baader micro guide eyepiece is still widely available and I may go for that one. The problem is finding a matching 12.5mm genuine ortho (Baader or Celestron) they are as rare as hen's teeth!

Roberto

#5 R Botero

R Botero

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Posted 19 August 2013 - 05:14 PM

Well, I thought I would report back on this. Got an old Celestron micro-guide reticle eyepiece and found out that the new Hutech Astro orthos matched the old Baader/Celestron Abbe Orthos (as former no longer in production).
Loaded them onto my Baader Mark IV tonight and they work! It takes some time to get used to it but brain does indeed merge the images - it helps if BV is well collimated - and measurements can be made using the binoviewer. For fainter star pairs - I'm into doubles - switching off the reticle illuminator is best and one ends with a couple of nice 12.5mm orthos...

Roberto






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