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Need of collimation?

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4 replies to this topic

#1 betacygni

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Posted 22 November 2019 - 11:56 PM

Just bought some Baader zooms for my televue binovues. Had a brief chance to try them out this evening, loved them so far, but unfortunately couldn’t get them to merge at the 8mm setting. Was ok at the 12mm setting however. I understand collimation issues get worse at lower focal length eyepieces, so wondering if I should reasonably expect them to be able to merge at the 8mm setting, and maybe this is indicating the binovues need a trip back to televue for collimation? While I can live with just the 12mm setting, the afov and eye relief on the zooms do get a bit nicer at the lower focal lengths, so would be cool to have available.

Edited by betacygni, 23 November 2019 - 12:17 AM.


#2 Eddgie

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Posted 23 November 2019 - 08:50 AM

As the focal length of the eyepieces get shorter, collimation error can be easier to see.  Now the common wisdom is that for binowiewers, it is better to get magnification by using amplifiers ahead of the binoviewer than after it, and while there are other good reasons for this, the issue you are dealing with is one of the main reason. 

 

The only way you would know if Televue thinks that the behavior is out of their design spec would be to ask them, and that is what I would do.



#3 junomike

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Posted 23 November 2019 - 09:03 AM

To check collimation I use the Lunar test as outlined in Post #2.

 

Before sending therm in for service, make sure the Zoom eyepieces are flush to the BV with no tilt.

Second, check that the 4 screws holding the eyepiece collets to the BV aren't loose.

Finally, there are tiny set screws on the side of the collets that hold the upper part (that turns to tighten/loosen) to the lower part of the collet that is fixed to the BV via the 4 screws mentioned above.  Check these also.

 

If you're really eager to have it fixed and confident in your abilities, here's how you can do it yourself.



#4 PETER DREW

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Posted 23 November 2019 - 04:26 PM

You could easily try rotating the whole zoom bodies in the eyepiece holders. The optics in the zooms might not be perfectly orthogonal.

#5 Steve D.

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Posted 02 December 2019 - 05:38 AM

Here's how I aligned mine.  What I don't know is whether this only aligned them for my specific IPD or for all widths.

 

 https://www.cloudyni...e/#entry8139541

 

Even if you decided not to align them yourself, this would at least let you know for sure. 




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