Micromega Critical Grain Focuser - 1) cleaning the mirror 2) reversing he mirror

Todd Barlow

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Aug 9, 2004
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I picked up a used Micromega Critical Focuser at a camera show today. The mirror is in fair to good shape.
1) Recomendations for cleaning? I have already tried the camels hair brush and compressed air.
2) The underside of the mirror is exposed and is in excellent condition - has anyone flipped the mirror? Any issues with reversing the mirror?

Thanks in advance

Todd
 

AllanD

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Hi Todd,

I have always assumed that what you are seeing on the underside is the back of the first surface mirror, so reversing it would give you two reflective surfaces in the optical path (a bad thing!) However, I haven't tried it so I could be wrong.

Cleaning would have to be done very carefully in the same way as one would clean the mirror in an SLR camera i.e. preferably not at all but if you must then with pure isopropyl alcohol and a very light touch. Check out the advice online re. cleaning first surface mirrors.
 

ic-racer

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I use Windex. New mirrors are available also. http://www.omegabrandess.com/products/Peak/130MIRROR
 

BobMarvin

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Several years ago someone gave me an Omega [Berkey-Omega] grain focuser which I haven't used because the mirror is in terrible condition. Instead I've continued to use a Microsight grain focuser, which works fine. Is Will the "Peak Replacement Mirror for MODEL 1" replacement mirror fit and, equally important, is the Omega better than the Microsight, which might justify spending the $36 that a replacement mirror costs?


 

BobMarvin

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I looked up the replacement mirror on the B&H website, where it's about $10 cheaper than buying it from the manufacturer. However I can see from their illustrations that my Omega focuser looks like the less expensive Peak model 2, which doesn't seem to have a removable mirror.
 

AllanD

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Just had a look at my focuser and can confirm that the first surface mirror is on a clear glass substrate so what you see from underneath is a second surface mirror. It is not coated on both sides so it should not be reversed.

Bob, the advantage of the Micromega/Peak focusers is that you can move to the edges of the projected image to check for sharpness into the corners. Only you can decide how much this feature is worth! I have found mine to be at least a comfort when printing big. Spending time aligning the enlarger properly is a better investment IMO.

Allan
 
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