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Reflector Mirror Cleaning

Optics Reflector DIY
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#1 BionicDan

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Posted 08 March 2021 - 01:43 PM

There are plenty of instructional videos and written procedures on cleaning mirrors. Most are similar with dish soap, cotton, distilled water etc... and I've had no problems cleaning mine without damage. I'm wondering if there any "best practices" for cleaning or who may have the most thorough instructions on cleaning. 



#2 SteveG

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Posted 08 March 2021 - 01:47 PM

The new trend is to ditch the cotton, and instead, use your fingers. It’s very simple, place the mirror in the sink, run water over it, using a drop of dish soap gently clean the surface with your fingers. If you feel something, don’t drag it across the mirror. Rinse, then do a final rinse with distilled water. Put it on its edge and let it air dry. Use a bulb blower for any remaining drops of water.


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#3 Mike G.

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Posted 08 March 2021 - 01:51 PM

I would add to that (just because I am OC) that I wash my hands thoroughly first, as much to clean them as to soften my skin on my fingers.  I have rather rough hands and tough skin and if my fingers are clean and soft, I don't worry at all. 


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#4 Spikey131

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Posted 08 March 2021 - 01:51 PM

This is all you need to know:  https://www.google.c...V0mvVqJ1melX4nB


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#5 belliott4488

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Posted 08 March 2021 - 02:46 PM

I would add to that (just because I am OC) that I wash my hands thoroughly first, as much to clean them as to soften my skin on my fingers.  I have rather rough hands and tough skin and if my fingers are clean and soft, I don't worry at all. 

This sounds neither O nor C to me! Our fingers have lots of tiny bits of abrasive dirt in the fingerprint grooves, and that can easily scratch a mirror. That's why technicians never touch high-end optical glass with bare fingers.

 

Maybe it doesn't matter since we're not exactly cleaning the primary mirror of the Hubble Space Telescope here, but I'd certainly clean my hands as well as possible before ever touching a reflector mirror. I imagine gloves would be better still, but I don't know what kind would be suitable for this purpose.


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#6 Jon Isaacs

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Posted 08 March 2021 - 04:22 PM

This sounds neither O nor C to me! Our fingers have lots of tiny bits of abrasive dirt in the fingerprint grooves, and that can easily scratch a mirror. That's why technicians never touch high-end optical glass with bare fingers.

 

Maybe it doesn't matter since we're not exactly cleaning the primary mirror of the Hubble Space Telescope here, but I'd certainly clean my hands as well as possible before ever touching a reflector mirror. I imagine gloves would be better still, but I don't know what kind would be suitable for this purpose.

 

Actually.. It's all done under water. Your fingertips are very soft, particularly when wet, and are extremely sensitive. A glove would get in the way.

 

Everything including ones hands needs to be clean. The mirror is rinsed first with lots of water. 

 

It's scary the first time but it's amazing how well it works. You basically just lightly massage the submerged surface of the mirror. Each fingertip has thousands of nerve endings, very light touch is possible and particles can be felt so as to avoid dragging them across the surface.

 

Here's a 25 inch mirror that had been quite dirty, it was in a case but was in a barn for a number of years, it cleaned up nicely.

 

Mirror 25 inch F5.jpg
 
Jon

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#7 belliott4488

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Posted 08 March 2021 - 07:01 PM

 

Actually.. It's all done under water. Your fingertips are very soft, particularly when wet, and are extremely sensitive. A glove would get in the way.

 

Everything including ones hands needs to be clean. The mirror is rinsed first with lots of water. 

 

It's scary the first time but it's amazing how well it works. You basically just lightly massage the submerged surface of the mirror. Each fingertip has thousands of nerve endings, very light touch is possible and particles can be felt so as to avoid dragging them across the surface.

 

Here's a 25 inch mirror that had been quite dirty, it was in a case but was in a barn for a number of years, it cleaned up nicely.

 

 
 
Jon

 

Thanks! You're inspiring me to give it a shot. I bought a second-hand 8" Newt last year that arrived with a nice layer of dust all over the mirror. I don't honestly know how much it affects the image, but I'd kind of like to clean it just to get a baseline so I'll know how long it's been since it was last cleaned.


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#8 bthrel

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Posted 08 March 2021 - 07:10 PM

The new trend is to ditch the cotton, and instead, use your fingers. It’s very simple, place the mirror in the sink, run water over it, using a drop of dish soap gently clean the surface with your fingers. If you feel something, don’t drag it across the mirror. Rinse, then do a final rinse with distilled water. Put it on its edge and let it air dry. Use a bulb blower for any remaining drops of water.

Just cleaned my ES 12" mirror exactly this way,,, works like a charm.


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#9 Jon Isaacs

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Posted 08 March 2021 - 07:15 PM

Thanks! You're inspiring me to give it a shot. I bought a second-hand 8" Newt last year that arrived with a nice layer of dust all over the mirror. I don't honestly know how much it affects the image, but I'd kind of like to clean it just to get a baseline so I'll know how long it's been since it was last cleaned.

 

Watch the video and follow the procedure.  In the past, I'd used cotton balls but the mirror never really came out bright and shiny. 

 

One thing:  Never dust off the mirror with a brush. I learned that lesson the hard way. It puts tiny scratches in the coating.

 

Jon


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#10 astropup

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Posted 08 March 2021 - 07:38 PM

Thanks for all the good info. I haven't had my dob out in years and this just motivated me to give it a good clean this week.


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#11 Stevencbradley

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Posted 08 March 2021 - 08:12 PM

I had to do this in 2004, with my Starmaster, due to the fires that ravaged SoCal in the fall of '03. According to what I read at the time, it was GENTLY rinse 1st, then use (Dawn) dish detergent with a soft cloth, then dry very carefully. No mention of fingers back then, except to avoid touching the front surface of the mirror with your fingers. I later decided to sell it, and at the buyer's request, I sent it to Rick Singmaster to have it given a going over. I must have done OK, because he told the buyer (as she later told me) that it was in "excellent shape." Funny aside: the buyer lived in Ocala, FL, to which my brother moved after remarrying. The buyer later emailed me that she was happy with the scope, which is about the best result one can have as a seller to a fellow amateur astronomer

#12 vtornado

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Posted 08 March 2021 - 11:00 PM

I use a tupperware dish to put the mirror in with the soapy water.   It can be rocked back and forth, and sometimes that is

all that is necessary to clean a dirty mirror.   Rinse with distilled, tip the  mirror on edge and chase any water drops off with

a squeeze bulb.   I do this first, and check if it is clean.  Nothing touches the mirror.

 

If it is not I repeat and use the finger tip.  


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#13 icomet

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Posted 08 March 2021 - 11:53 PM

http://www.rfroyce.c...leaning_new.htm

 

 

Clear Skies.



#14 Jon Isaacs

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Posted 09 March 2021 - 06:08 AM

 

Have you used this technique?

 

Jon



#15 Rob Willett

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Posted 09 March 2021 - 06:35 AM

Just about to look for a thread on this subject as I have a dirty old 6" mirror I found in a barn.

 

thanks

 

Rob



#16 Neil_Phan

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Posted 11 March 2021 - 12:30 AM

After botched my first attempt at washing my SCT mirror. I removed the darn thing. Filled the sink with distilled water to the mirror surface. Add a few drops of Dawn dish soap. Used an eyeglasses microfiber towel to clean. Them rinsed the whole thing with a jug or two of distilled water and let the mirror stood for an hour. Success. 



#17 Jon Isaacs

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Posted 11 March 2021 - 07:25 AM

After botched my first attempt at washing my SCT mirror. I removed the darn thing. Filled the sink with distilled water to the mirror surface. Add a few drops of Dawn dish soap. Used an eyeglasses microfiber towel to clean. Them rinsed the whole thing with a jug or two of distilled water and let the mirror stood for an hour. Success. 

Personally I would not use any fiber to clean a mirror.  But SCT mirrors are unlikely to be as dusty as a Newtonian mirror so the embedded dust issue that is a concern with the exposed mirror of a Newtonian is not such a concern with an SCT.

 

Jon



#18 Starman1

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Posted 12 March 2021 - 04:00 PM

shocked.gif bigshock.gif foreheadslap.gif gaah.gif Just. No. Way.




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