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  1. #1

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    Micromega Critical Focuser Lens cleaning

    Hello, I have one of the Micromega Critical focuser units (Prof. Z. Koana) and it's in fine shape other than the inner elements need a cleaning. Is this a difficult task for someone with limited experience?
    Does anyone have any tips/diagrams/info they could share?
    If it is not advisable for a home job, does anyone know where I can send my focuser to be cleaned?

    This is not fungus, if you wonder. It looks like many tiny dust specs and and overall residue, like maybe someone smoked heavily in the darkroom (hard to describe). It's odd to me that the microscope inside would get dirty. It seems like a pretty closed atmosphere, but it's very distracting when trying to view the grain of a fine grained enlargement.
    Should I just get a pair of lens calipers, some lens cleaning supplies, and a few hours and try this myself?

    Many kind thanks, I hope everyone has a safe holiday, whatever it might be.

    EDIT. Actually, it looks like the bottom element (closest to the mirror) is the main culprit....maybe this is not to bad for a home clean. Opinions sought.

  2. #2
    ic-racer's Avatar
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    I found one like new in box with foggy elements. After cleaning it was better than my 10 year old unit, so I cleaned that one up also. I believe it comes apart by removing the lens retaining ring on the bottom of the objective.

    You might consider sending it off if you have not disassembled a lens before. If you get this back together wrong, it is useless.
    Last edited by ic-racer; 12-23-2012 at 03:32 PM. Click to view previous post history.

  3. #3
    Bill Burk's Avatar
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    Quote Originally Posted by ic-racer View Post
    If you get this back together wrong, it is useless.
    Yes, we had quite a discussion going and in the long run, I think that's what happened here...

    http://www.apug.org/forums/forum41/1...repancies.html

  4. #4

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    Well, I'm glad my search for "cleaning critical focuser" didn't bring up that post, or I never would have tried it today!
    Luckily, like I thought, it was the rearmost "element" that was dirty. It's not really an element but just a piece of glass with a rectangle etched into it. I did as ic-racer describes and removed the 3 retaining screws (but next time I won't remove them, just loosen them a lot...if they fall and get lost they are tiny). The rear retaining assembly comes out of the shaft with a twist and pull; it doesn't screw in. The rear glass can then be removed from the inside of the retaining assembly with simple finger pressure on the inner retaining ring. I cleaned it up (it was nasty and foggy) and now it's like a brand new finder. I'm amazed that it got so junky in there. Thanks for the replies. If anyone needs to clean just the bottom glass from the inside out it's very easy. Just look to see what side the rectangle etching is on before removing that glass and put it back like it came out (I can't remember right now).



 

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