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Easier to converge: Narrow or Wide FOV?

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#1 blakestree

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Posted 27 February 2021 - 12:58 PM

I should rather know this, but I don't. What's the answer?



#2 Reid W

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Posted 27 February 2021 - 01:13 PM

My guess would be- it doesn't matter.

 

Exit pupil on the other hand?  Small exit pupil is "less tolerant to mechanical shortcomings".  


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#3 Astrojensen

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Posted 27 February 2021 - 01:21 PM

It doesn't matter. What matters is focal length. The shorter the focal length, the more difficult it can be to merge the views, unless the collimation of the binoviewer is perfectly spot on and the eyepiece holders hold the eyepieces perfectly square. 

 

 

Clear skies!

Thomas, Denmark


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#4 blakestree

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Posted 27 February 2021 - 01:47 PM

Thanks, chaps!



#5 Jeff B

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Posted 27 February 2021 - 05:39 PM

It doesn't matter. What matters is focal length. The shorter the focal length, the more difficult it can be to merge the views, unless the collimation of the binoviewer is perfectly spot on and the eyepiece holders hold the eyepieces perfectly square. 

 

 

Clear skies!

Thomas, Denmark

And the eyepieces are actually round with the element stack centered precisely on the centerline of the eyepiece.  You will at times find the culprit of merging difficulties with a particular eyepiece pair is actually due to small imperfections in the mechanical construction of the eyepieces themselves.   That's where rotating one or both eyepieces in their holders can help a lot with merging issues.

 

Jeff


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#6 faackanders2

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Posted 01 March 2021 - 11:19 PM

I should rather know this, but I don't. What's the answer?

Easier to merge/converge low power vs. high power.



#7 noisejammer

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Posted 03 March 2021 - 12:15 AM

My experience is that a misalignment is far more visible at high powers than it is at low. My eyes can pull a small angular displacement together but there's a limit. I exploit this when collimating my Denk II's.

 

I've also noted that when the exit pupil approaches 0.5 mm, I have to be very careful with the IPD adjustment - if I don't nail it, either one or the other eye can't see the image.


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