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APM 100mm Temporary/Bodge Collimation

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5 replies to this topic

#1 RickyD85

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Posted 19 June 2019 - 04:20 AM

Hi guys

Ive taken my APM’s to a forest holiday, they went in their carry bag in the boot of my car and unfortunately it looks like they have been knocked out of collimation on the journey here.

Looked through them and seeing double on all the stars.

Can i temporarily adjust the collimation? It doesn’t have to be perfect but currently they are pretty much unusable.

Edited by RickyD85, 19 June 2019 - 04:20 AM.


#2 markb

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Posted 19 June 2019 - 06:56 AM

Does this happen with all eyepiece pairs? If you only have the pair that came with the binos I might do the swap eyepieces / rotate eyepieces to see if it is an eyepiece knocked out of whack, not the binos.

 

Remember the role of eyepiece optical axis errors, https://www.cloudyni...f-apm-100-bino/ .

 

I also found the removing and reinserting eyepiece can resolve temporary issues, probably related to eyepiece holder clearances.

 

Check the eyepiece holders too, the orings can break, and a partial print can decent er an eyepiece. I used my fist pair without the orings, without issue.

 

APM has a tool available for home collimation. It is pictured on their site and in CN discussions.

 

https://www.cloudyni...m-120100-binos/

 

I have collimated 3 pairs of old 1950s-1960s binos with a large lens spanner as well as plastic spudgers and modified wooden tools (to avoid collimation eccentric ring damage and slipped tool damage). It is tricky, and may take reorienting both sides to reach collimation where the barrels have been turned, on those old zinc screw on barrel types, not applicable here. The hardest part on fixed eyepieces is getting target (I did this in daylight) truly centered. I think I used a method where I moved my eye well away from the eyepiece to reduce the visible portion to a small area. It may also be possible todefocus an articicial or real star to allow matching the defused circle to the field edge.

 

I never touch prisms, hoodoo is required. 

 

Also, contact Suddarth, the bino experts. They are great and said to be affordable.

 

Yours sounds like it will need the true collimation with a tool though; it cannot hurt to swap and also rotate the eyepieces first.

 

Good luck.


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#3 Rich V.

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Posted 19 June 2019 - 10:18 AM

For temporary alignment, if rotating the eyepieces doesn't help, by all means try to see if there is "wiggle room" with the eyepieces in the focusers.  It's the only variable you have to work with.

 

I don't see how the APMs would be easily knocked out of collimation unless somehow a prism shifted by an impact. The prisms are not intended to be user adjusted.  I wouldn't expect the eccentrics to turn by themselves; they shouldn't be that loose.

 

Rich


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#4 garret

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Posted 19 June 2019 - 10:27 AM

 

Looked through them and seeing double on all the stars.

What magnification?

 

If the upper prism assembly has been bumped or shift relative to the main body it result in de-collimation, I know this from my own experience.

Even a very slight shift result in de-collimation, but the 4 screws (2 hex) keep the upper body precisely into the right position. 

 

Garret v/d Veen

 


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#5 markb

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Posted 19 June 2019 - 10:12 PM

I agree with Rich and Garret, I was not clear that that was the reason I suggested Suddarth; prisms take the magic touch they have offered for over a decade, no foreign shipping required.

It may be possible to compensate for a small prism shift with the eccentrics, however.
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#6 RickyD85

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Posted 20 June 2019 - 06:48 AM

Many thanks for the fix!

So I simply unscrewed the locking rings all the way, swapped the eyepieces and locked them up again and everything is working perfectly again!

I’ve experienced similar before (not as bad) and thought it must have just been my eyes on that particular day. Must have been the way the eyepieces were seated or ‘twisted’ then.

Anyway, many thanks again not only can I use them, I don’t need to worry about getting them fixed

Oh and garrett, to answer your question, I am using 12.5mm Baader Morpheus (so giving me 44x)

smile.gif

Edited by RickyD85, 20 June 2019 - 04:00 PM.



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