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Ruined corrector plate coating with Zeiss lens cleaner

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#1 genericnj

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Posted 22 March 2019 - 09:01 AM

I recently purchased a never used MTS-SC8 -- old school 8in SCT with pedestal stand and lx motor drive. It was in all original packaging with manuals and everything included. I paid a good penny for it, but was excited to get an old model in immaculate new condition... There was some dust on the front corrector plate which I wanted to clean just to have the telescope in absolutely new condition and I used Zeiss lens cleaner - which states on the bottle safe for all lens coatings.... Well with one spray of the stuff, as I wiped with the microfiber cloth, it completely removed the lens coating.... now I have half a corrector plate with coating, half partially or completely uncoated. It seemed like there was 2 layers of coating because some parts have still some coating, and some have none ... this is from one spray of the bottle... 

 

I understand I cannot replace the front corrector plate without replacing the mirror as they are matched -- are there any other options to have it recoated? it absolutely kills me that I had a mint telescope that I paid a lot of money for and trying to be diligent I used what I thought was the best lens cleaner and ended up ruining it....

 

Attaching pic. Any advice very welcome

Attached Thumbnails

  • meade 8in damage.jpg

 

#2 genericnj

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Posted 22 March 2019 - 09:09 AM

Attaching a slightly better photo of it...

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  • 8in2.jpg

 

#3 gnowellsct

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Posted 22 March 2019 - 09:35 AM

It seems unlikely that you are in fact removing the coating, though I suppose you could test the hypothesis with a different brand of lens cleaner. I like techspec lens cleaning fluid from Edmund optics.

In other words I only think your lens cleaner is removing coatings if you're victim of some kind of industrial sabotage.

Coatings are fused into the glass and only things like nitric acid can harm them. If you sand papered your corrector you could get the coatings off by grinding through them through to the underlying glass.

An alternative hypothesis is that the corrector is so grimy that the clean area looks like something is wrong with it when it's the other way around. The pic is hard to see. Put a bright light on it and try one more?

If you HAVE removed coatings with a lens cleaner it will be something of a first. Even for Meade...
 

#4 Cali

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Posted 22 March 2019 - 09:36 AM

Sorry to read this. Wondering if the Zeiss lens cleaner is the only culprit.

 

- Cal


 

#5 mclewis1

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Posted 22 March 2019 - 09:39 AM

I'd be very very surprised if you have actually removed the factory applied coating (assuming you aren't also using an abrasive pad with the liquid). Given the age of the scope and the cleaning fluid used I think you have actually removed old build up on the corrector (over time the build up has come from something where it was stored and it was deposited in small amounts so appears to be a uniform coating).

 

I'd continue cleaning the whole corrector and be done with it ... just use the scope. If for some strange reason you have removed the optical coating finishing it off won't make it any worse and in the more likely situation you will have just properly cleaned the whole corrector.


Edited by mclewis1, 22 March 2019 - 09:40 AM.

 

#6 genericnj

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Posted 22 March 2019 - 09:42 AM

i cleaned the rest of the element with isopropyl 90% 10% water and a hint of dish soap and it did not do any harm to the remaining coatings or affect it in any way -- I even put quite a bit of pressure when cleaning the rest to test if it would come off, it would not budge no matter how much pressure was applied. I used the microfiber cloth that came with the zeiss cleaner.

 

The telescope was in box it is in amazing shape -- I just stupidly wanted it perfectly clean when honestly it did not even need a cleaning of the element ... it is definitely the coating coming off -- the remainder that is still there is perfectly uniform so would not have been dirt or grime... :(


 

#7 genericnj

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Posted 22 March 2019 - 09:45 AM

.. also it seems clearly 2 layers of coating, the top layer is a tad darker brownish looking that reflects less light than the bare glass, then a layer under the top is darker greyish layer, then bare glass. Anywhere on the coating where a drop of the spray went on seems to have eaten the coating away. Also when i sprayed it and wiped, it had a rainbow effect as it came off the element.

 

The Zeiss spray was brand new i bought off amazon yesterday just for this purpose..


Edited by genericnj, 22 March 2019 - 09:46 AM.

 

#8 Asbytec

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Posted 22 March 2019 - 09:45 AM

Coatings have some color to them. Holding it up to a light at a proper angle should show some color depending on the type of coating.

I tend to agree, its not likely the lens cleaner removed the coating. But you may be able to verify it by checking for some color on the cleaned area
 

#9 Paul G

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Posted 22 March 2019 - 09:46 AM

I have seen an older Meade 8 with a failed coating on the corrector plate. The corrector looked cloudy and the coating came off in little flakes over large areas with gentle cleaning (Kodak lens cleaning solution and surgical roll cotton). It lost its adhesion to the glass, cloudy areas were where it had detached, cleaning just removed what had already failed. Sounds like your situation was similar, a healthy coating would not have come off with the Zeiss cleaner.


 

#10 jupiter122

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Posted 22 March 2019 - 09:49 AM

Assuming that your mirror is in fact damaged then:

 

I am not a telescope maker and am not familiar with mirror coatings, but if you think a reasonable argument can be made that a "mirror coating"  constitutes a "lens coating" then the representation on the bottle that the cleaner was"safe for all lens coatings" may have been false. In that case, you may want to consider making a claim for "misrepresentation" or "breach of express warranty" against the retailer from whom you purchased the cleaner and ask them to pay for repairs or replacement of the mirror. If, however, the product came with a disclaimer--on the bottle, with the packaging, or on any website you may have used to purchase it--like "no liability for consequential damages"(that's what the damage to the mirror is) or "your remedies are limited to replacement of the product or refund," you may be out of luck.  

 

Just saw that you bought it on amazon.com.  Amazon's terms and conditions exclude liability for consequential damages, but if the seller was not amazon itself, but just a seller placing items for sale on amazon, you might have a claim against them.  


Edited by jupiter122, 22 March 2019 - 09:54 AM.

 

#11 gnowellsct

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Posted 22 March 2019 - 10:08 AM

The Zeiss spray was brand new i bought off amazon yesterday just for this purpose..

It's possible there is fraud st work and it's not really Zeiss. Amazon sells phone chargers marked Samsung that short out and don't work, even blow up. They cost $7. I was slow to realize they were fakes because they said Samsung and there were dozens of vendors.

After having a couple of those I went to best buy which has a marketing agreement with Samsung. I figured they wouldn't sell fakes, and the prices were much higher. I paid $30 for a charger that works. 98% positive reviews, compared to 50% for the fakes on Amazon.

Still it's hard to believe you have something removing coatings. Even if it is fake.

You could contact Zeiss. Amazon is no guarantee of quality. The opposite, in fact. Buy optics cleaners from B&H or Edmund Optics.

Edited by gnowellsct, 22 March 2019 - 10:12 AM.

 

#12 genericnj

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Posted 22 March 2019 - 10:10 AM

Just for clarification, this isnt the mirror coating, but the corrector plate, which is a lens. Based on the product it definitely states safe for ALL lens coatings and was not safe for the coating on this lens element :/

 

 

Assuming that your mirror is in fact damaged then:

 

I am not a telescope maker and am not familiar with mirror coatings, but if you think a reasonable argument can be made that a "mirror coating"  constitutes a "lens coating" then the representation on the bottle that the cleaner was"safe for all lens coatings" may have been false. In that case, you may want to consider making a claim for "misrepresentation" or "breach of express warranty" against the retailer from whom you purchased the cleaner and ask them to pay for repairs or replacement of the mirror. If, however, the product came with a disclaimer--on the bottle, with the packaging, or on any website you may have used to purchase it--like "no liability for consequential damages"(that's what the damage to the mirror is) or "your remedies are limited to replacement of the product or refund," you may be out of luck.  

 

Just saw that you bought it on amazon.com.  Amazon's terms and conditions exclude liability for consequential damages, but if the seller was not amazon itself, but just a seller placing items for sale on amazon, you might have a claim against them.  


 

#13 genericnj

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Posted 22 March 2019 - 10:13 AM

I would be surprised if it was a fake item -- It would cost them more to produce a lens cleaner than they would make on it. The cleaner has a very 'windex-like' ammonia smell -- i am guessing it has strong ammonia that caused the coatings to fail -- it could be that the coatings being old had a higher likelihood of failing -- but scrubbing with isopropyl alcohol does not cause it any harm, whereas gentle wiping with the zeiss cleaner took it right off..

 

 

It's possible there is fraud st work and it's not really Zeiss. Amazon sells phone chargers marked Samsung that short out and don't work, even blow up. They cost $7.

After having a couple of those I went to best buy which has a marketing agreement with Samsung. I figured they wouldn't sell pirated fakes. I paid $30 for a charger that works. 98% positive reviews, compared to 50% for the fakes on Amazon.

Still it's hard to believe you have something removing coatings.

You could contact Zeiss. Amazon is no guarantee of quality. The opposite, in fact. Buy optics cleaners from B&H or Edmund Optics.

 

Attached Thumbnails

  • zeiss.jpg

Edited by genericnj, 22 March 2019 - 10:19 AM.

 

#14 genericnj

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Posted 22 March 2019 - 10:17 AM

The areas that did not lose the coating definitely have a hint of darker / brownish color that is very uniform -- the areas where coating came off are just clear glass, slightly more reflective, and reflection is more whiteish in color (you can see in 2nd pic i posted especially where left side is coated, right side is where coating came off)..

 

 

Coatings have some color to them. Holding it up to a light at a proper angle should show some color depending on the type of coating.

I tend to agree, its not likely the lens cleaner removed the coating. But you may be able to verify it by checking for some color on the cleaned area


 

#15 PETER DREW

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Posted 22 March 2019 - 10:34 AM

Corrector coatings on early Meade SCT's were quite light in colour. I was a Meade dealer at the time and I never saw a brownish colour. I would continue to clean with the zeiss cleaner to provide a uniform finish. Try a piece of cotton wool and see what colour it assumes after use.
 

#16 rachnoman

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Posted 22 March 2019 - 10:36 AM

I have seen an older Meade 8 with a failed coating on the corrector plate. The corrector looked cloudy and the coating came off in little flakes over large areas with gentle cleaning (Kodak lens cleaning solution and surgical roll cotton). It lost its adhesion to the glass, cloudy areas were where it had detached, cleaning just removed what had already failed. Sounds like your situation was similar, a healthy coating would not have come off with the Zeiss cleaner.

If the corrector plate is not cleaned properly the coating will not bond to the glass. Also, the cheaper "soft" coatings do not stand up to any type of cleaning. I have seen similar effects in some of their eyepieces.


 

#17 genericnj

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Posted 22 March 2019 - 10:36 AM

sorry i may be exaggerating saying brownish -- it is a very subtle coppery color reflecting off the sun -- see the left side of the element in the below pic.

 

 

Corrector coatings on early Meade SCT's were quite light in colour. I was a Meade dealer at the time and I never saw a brownish colour. I would continue to clean with the zeiss cleaner to provide a uniform finish. Try a piece of cotton wool and see what colour it assumes after use.

 

Attached Thumbnails

  • 8in2.jpg

 

#18 Paul G

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Posted 22 March 2019 - 11:13 AM

Regardless, it shouldn't affect the views through the scope. Might lose a few percent transmission but that is well below the threshold of visual detection so I wouldn't sweat it.


 

#19 Toddeo

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Posted 22 March 2019 - 11:42 AM

Looks like some sort of "grime" to me. I've had quite a few sct's-still have three. I've never seen coating on a sct that was a brownish-copper tint to it.  I have a 30+ year old Meade 8" sct- just took it apart and cleaned the corrector and primary. Just used windex and distilled water. The views are now fantastic! As long as you have cleaned part of the corrector- you might as well finish it. Your views will be fine.


 

#20 Reid W

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Posted 22 March 2019 - 11:54 AM

Looks like the coating is still there on the "cleaned" area, and the stuff that appears to be a coating could be an oxidation or similar material.


 

#21 Binojunky

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Posted 22 March 2019 - 12:09 PM

I had a similar experience a few years back, it was a Lomo MiniMak scope, I used a Zeiss wipe , the type sealed in individual packets, brought the coating right off,D.


 

#22 genericnj

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Posted 22 March 2019 - 12:33 PM

Looks like the coating is still there on the "cleaned" area, and the stuff that appears to be a coating could be an oxidation or similar material.

Unfortunately the cleaned area looks like straight glass, it definitely has lost coating -- very hard to capture in the photo but in person it is very clear -- and the coated area is impossible to 'clean' the coating off with anything and no matter how much i scrub so i trust it is the original coating -- the only thing that takes it right off is the zeiss cleaner. I even tried one small additional section..

 

I had a similar experience a few years back, it was a Lomo MiniMak scope, I used a Zeiss wipe , the type sealed in individual packets, brought the coating right off,D.

I'm guessing it was the same chemical solution -- what did you end up doing in your case? did you end up just stripping the rest of the coating off or left some on and some off ? 


 

#23 genericnj

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Posted 22 March 2019 - 12:38 PM

This photo shows the problem even better -- you can clearly see the two layers of coating from left to right top coating in the coppery color, then greyish coating, then plain glass...

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  • 20190322_133454.jpg

 

#24 KLWalsh

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Posted 22 March 2019 - 01:14 PM

This photo shows the problem even better -- you can clearly see the two layers of coating from left to right top coating in the coppery color, then greyish coating, then plain glass...


Even the ‘glass’ area doesn’t look especially shiny. You can verify that it’s plain glass by taking a piece of window glass and blackening one side with black paint, then comparing the unpainted surface with your corrector. If the coating has actually been removed it will look as shiny as the unpainted glass.

But as was mentioned before, the net affect on performance will be almost negligible.

Btw- I’ve seen it happen a number of times that an AR coating fails. As an optics engineer I see a lot of coated glass. Glass prep errors, coating machine failures, missed steps in the coating process - these things do happen.
 

#25 Sketcher

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Posted 22 March 2019 - 02:42 PM

Try looking through the corrector plate, at the primary mirror.  Does the mirror appear to be brighter/clearer when looking through the cleaned (Zeiss) portion of the corrector or when looking through the still-coated portion of the corrector?

 

If it's brighter through the cleaned (Zeiss) portion of the corrector, then the remaining "coating" (regardless of what it is) is causing more harm than good and performance will be enhanced by cleaning the rest of the corrector plate using the Zeiss product.

 

The colors (brownish and grayish) of the film layers on your corrector plate don't look like those from any low-reflective coatings that I've ever encountered on astronomical telescopes (blueish - purplish - greenish).

 

You mentioned that the cleaned (Zeiss) part of the corrector was more reflective than the still coated part.  That, to me, would be another indication that it wasn't a low-reflection coating that was removed.  Such optical coatings tend to be just as highly reflective as uncoated glass, but only at selective wavelengths (colors).

 

My current "best-guess" is that the coating that was removed was residue from some type of fine smoke or chemical(s) that the scope had been exposed to -- perhaps on two different occasions.

 

What does the reflection of a white light bulb look like (intensity and color) from the cleaned (Zeiss) vs. still coated portions of the corrector plate?


 


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