Clean this? Looking down my eyepiece tube.

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xioz
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Clean this? Looking down my eyepiece tube.

#1 Post by xioz » Tue Sep 20, 2022 12:57 pm

Hi all,

Is this worth trying cleaning in my Olympus CH B monocular head? Not sure if it is fungus/mold, coating separation due to age or just fibers from a previous owners attempt to clean it. As I understand it might be reducing the resolution/brightness slightly, but how much?
DownCHBtube.jpg
DownCHBtube.jpg (24 KiB) Viewed 1558 times
Thank you for any help.

apochronaut
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Re: Clean this? Looking down my eyepiece tube.

#2 Post by apochronaut » Tue Sep 20, 2022 2:22 pm

There will be a prism or possibly mirror system in the bottom of a monocular head but most likely a prism. Airborne debris and film will build up on the surfaces over the years, sometimes mould.
I am not familiar with that tube but commonly the deviating prism is mounted to a backing plate which also forms the base of the head. Usually removing 3 screws at the apexes of an isoceles triangle will drop the prism out for cleaning.

To avoid scratching surfaces I usually blow on the surfaces initially in case there are loose particles. Then to remove those that cling, flood each surface with either ipa or a mixture of water, ipa, white vinegar and detergent. Something like a tbs. water, tsp. ipa, 1/4 tsp. vinegar plus 1 drop of dish detergent will do. You only use enough to cover the surface. Isopropyl alcohol will do if it is just dust but usually there are airborne vapourized oils that have distilled out as well. Cigarette smoke, cooking, lab experiments, so the vinegar and detergent help to cut and saponify those some.
Flood the surface then remove the looser debris by dragging a tissue corner lightly over the surface. This sops up the liquid and removes any loose particulate matter that might be there : aluminum oxides or tiny metal particles that might have dropped down out of the tube over time. Aluminum threads can relase those to gravity.
Usually then it is safe to wipe the surface with a soft cloth and or swabs. Use ipa on a swab , then follow up with more swabs to dry and polish the surface.
Your optical tube looks pretty murky. Intensity and contrast are the victims with resolution affected due to both.

There also looks to be some film and possibly mould on the optical window in the top of the tube. IPA works pretty good on mould too, as long as it isn't too bad. If you have mould, it doesn't look to be that bad ....I don't see the typical manifestation of a really bad case in the photo.

Sure Squintsalot
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Re: Clean this? Looking down my eyepiece tube.

#3 Post by Sure Squintsalot » Tue Sep 20, 2022 4:50 pm

Sounds like useful cleaning advice...thanks Apo!

What does one do for older, cloudy or foggy objectives? I've got an old Zeiss 40x that seems to get cloudy over a few months after cleaning the interior of the objective. The 10x and 2.5x stay clean and crisp.

PeteM
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Re: Clean this? Looking down my eyepiece tube.

#4 Post by PeteM » Tue Sep 20, 2022 10:48 pm

That looks like fungus to me - perhaps caught early enough to avoid damage to the coatings.

If so, one approach to cleaning is IPA (isopropyl alcohol) or vinegar as Apo suggested. Potentially a more effective one is a diluted mix of ammonia and hydrogen peroxide. Should be Web sources with the proper percentages.

You'll want to keep relative humidity below 55RH or so to keep it from returning.

Phill Brown
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Re: Clean this? Looking down my eyepiece tube.

#5 Post by Phill Brown » Wed Sep 21, 2022 9:49 am

I have 100% success with ziess coated lens cleaner spray. It's not expensive. Still on my first bottle.
Looks like fungus which so far has not permanently damaged any coating I've cleaned.
Tried IPA and various home brews which left outlines of fungus on prisms and lens coatings, assumed they where damaged but not the case.
If the parts are clamped try to mark where they are to make it more likely they line up when it goes back together.

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xioz
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Re: Clean this? Looking down my eyepiece tube.

#6 Post by xioz » Thu Sep 22, 2022 3:46 am

Thanks all for the tips, I will gird my loins and give it a go.
Phill Brown » Wed Sep 21, 2022 7:19 pm

I have 100% success with ziess coated lens cleaner spray. It's not expensive. Still on my first bottle.
So lens cleaner spray for 'coated lenses' as in eyeglasses? Thanks I will have a look around and see if there is some different formulas.
Most of the ones I have seen have isopropyl alcohol as the ingredient in any case.

Phill Brown
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Re: Clean this? Looking down my eyepiece tube.

#7 Post by Phill Brown » Thu Sep 22, 2022 11:08 am

Prisms,lenses coated or not.
First surface mirrors is spray on and allow residue to run off, repeat a few times without letting anything dry on. I choose not to use any method for first surface mirrors that involves physical contact, including lens paper, older first surface mirrors can have a patch where light has thinned the coating or left a dull area that is best lived with.
Zeiss coated lens cleaner doesn't smell of IPA so my guess is it's not got much if any.
Air blower first,tip of a clean 000 brush will pick up visible dust if you have just a few particles. It's' not good practice to spray directly onto a lens assembly.
Capillary action will draw it in around the edges.
Sensor cleaning brushes use static attraction but if £5 sounds too much for spray my guess is they are beyond the maintenance budget.

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xioz
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Re: Clean this? Looking down my eyepiece tube.

#8 Post by xioz » Sat Sep 24, 2022 1:23 am

I have a basic cheap lens cleaning kit with a air blower/brush, but no sensor brush I might check out a photography store and see what they have.

I didn't say 5 pounds was too much BTW! Maybe the Ziess spray is everywhere in the UK, but I haven't seen it here in the stores or on eBay. We don't have a retail microscope hobby store in my city, so I have been buying most of my stuff online.

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xioz
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Re: Clean this? Looking down my eyepiece tube.

#9 Post by xioz » Sun Sep 25, 2022 1:19 pm

Thought I would show the difference after I had a go in cleaning the prism, for other beginners at least!
My first attempt. I got the fungus threads off, but smudged the glass with the lens paper.
PXL_20220925_105410154a.jpg
PXL_20220925_105410154a.jpg (114.07 KiB) Viewed 1183 times
My second attempt, I was not so gentle and used a lot more IPA, and a lot more polishing, also with a lens cloth.
IMG_20220925_220905(1).jpg
IMG_20220925_220905(1).jpg (102.17 KiB) Viewed 1183 times
Not sure it was affecting the viewing much, but at least the growth can't get worse now.

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xioz
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Re: Clean this? Looking down my eyepiece tube.

#10 Post by xioz » Mon Sep 26, 2022 1:06 am

*bump*
Looks like we will have to check if the spam bot is in the middle of a posting spree before posting for the moment... ;-(

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