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Is my Binoviewer collimated

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#1 Nessark

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Posted 28 June 2020 - 10:30 PM

Hello, I have a Celestron binoviewer. I think I may have collimation issues with it.

Pointed my binoviewers at my kitchen cabinets 38'10.5" (thirty eight feet and ten and a half inches) away. Then upon switching the collimation laser with each eyepiece socket I saw there was a half inch of space separating the markings. Are my binoviewers with terrible collimation?

I made 2 pencil dot markings on my cabinets. They are diagonally spaced. Is this normal for binoviewers?



https://i.imgur.com/24MZO0T.jpg
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#2 TOMDEY

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Posted 29 June 2020 - 03:02 AM

Please confirm... you are doing this with the naked binoviewer... no telescope and no eyepieces... right?

 

If that is the case, you are measuring differential field tilt... not what matters, which is the vergence vector. To quote the one and only expert I know, Bill Cook, in his book Binoculars: Fallacy and Fact, p.94 >>>

 

"The US Navy trained its Opticalman personnel to use the goal of 2 minutes of step (dipvergence, or vertical image separation), 2 minutes of divergence (lateral image separation), and 4 minutes of convergence (image crossover)."

 

What you are doing does not measure that... not at all.

 

Binocular collimation is one of the least understood and most misunderstood optical alignment topics out there. What you should do is take a small telescope and mate it to the shortest focal length eyepiece you have (ideally a pair)... and aim that at something structured, far enough away to achieve good focus, both sides. Because it is a binoviewer, not true binos, the target doesn't have to be far away or a collimator. Scrutinize that for vergence issues. The vergence improves, proportional to the inverse of eyepiece focal length. So, e.g. if you intend to use 10mm eyepieces... testing with 3mm will manifest three times worse, so be easier to quantify. That's really all there is to it!

 

I can provide more guidance, regarding quantification, if you like.   Tom


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#3 TOMDEY

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Posted 29 June 2020 - 03:07 AM

PS: You don't need a collimator (as you would for true binoculars) because the binoviewer is beamsplitted through the same telescope... so the target can be down range but relatively close... provided you can bring it to focus.    Tom



#4 Nessark

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Posted 29 June 2020 - 07:20 AM

Thanks for the info Tom. I previously used two 23mm eyepieces and had no issues merging images but after a few minutes I started getting headaches from eystrain I'm guessing. So I figured there may be collimation issues with the binoviewer.

#5 Nessark

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Posted 29 June 2020 - 07:20 AM

Actually I used a 2x Barlow with that as well so it was actually 11.5mm not 23.

#6 decep

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Posted 29 June 2020 - 11:39 AM

Make sure your laser is collimated.  You can spin the laser in the holders and make sure the resulting dots do not move too far.



#7 Miranda2525

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Posted 30 June 2020 - 08:16 PM

Hello, I have a Celestron binoviewer. I think I may have collimation issues with it.

Pointed my binoviewers at my kitchen cabinets 38'10.5" (thirty eight feet and ten and a half inches) away. Then upon switching the collimation laser with each eyepiece socket I saw there was a half inch of space separating the markings. Are my binoviewers with terrible collimation?

I made 2 pencil dot markings on my cabinets. They are diagonally spaced. Is this normal for binoviewers?



https://i.imgur.com/24MZO0T.jpg

Have you tested them in your telescope first?




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