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Cleaning corrector lens with XLT coating

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#26 rmollise



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Posted 05 July 2013 - 04:20 PM

They should be so perceptive. :lol:

#27 Stacy


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Posted 07 July 2013 - 11:00 PM

It is unclear on the "ammonia" that is in Windex. The manufacturer says it is "Ammonia D," but is reluctant to describe exactly what that is.

Not really sure where you are getting your information. The company that makes Windex (Johnson & Son) is quite clear about the ammonia used in their product. They also do not recommend it's use on surfaces that would suffer from ammonia.

This is a lively discussion however, and I would love to see what the scientific community has to say about it. :ubetcha:

Uncle Rod says it's safe and effective. I believe it's potentially harmful to your coatings.

I am going to call Celestron tomorrow, and see what they say about it. I actually hope Uncle Ron is correct, because my corrector needs a good cleaning, and that would simplify the whole process... However, I doubt they will say much more than what's in the official manual, which has already been posted......

Ammonium Hydroxide (From Johnson & Son website)

Ammonium Hydroxide is commonly referred to as ammonia and is found in air, soil and water. Many consumers use it at home for cleaning and laundry. It’s a cleaning agent that removes dirt, and it can also be used as a pH adjuster that alters the pH of a product to improve stability. Every formula has an optimum pH to make it work best. For example, a formula that’s more acidic works better for soap scum removal. Its opposite, a formula that’s more alkaline, might be more effective at removing grease or greasy soils. We use pH adjusters to make sure we achieve the best pH for a particular job. Also, the pH of a formula can affect how long it lasts within a container – for example limiting its tendency to rust in a steel can. Household ammonia has a strong odor; by using Ammonium Hydroxide in combination with other ingredients, we can achieve the same cleaning results while using much less ammonia.

#28 astroman100082


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Posted 08 July 2013 - 02:24 PM

Thank you very much for your help guys! I appreciate it!

#29 Stacy


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Posted 09 July 2013 - 03:28 PM

Called Celestron and they were non-committal as expected. However a little research provided some insight into the issue.

Al Nagler mentions Windex on the TeleVue website as a potential cleaner, that used sparingly, is safe and effective on TeleVue eyepieces.

Another important item to consider is what is the nature of the dirt? Is it water soluble?

A quick Google search on "windex optics" reveals more of the story. It's a hotly debated topic on many web forums from hunting to photography. Many are for and many are against, and just about everybody cites a personal experience either good or bad to back up their opinions.

The simplest argument against it's use however was from someone who had not tried it. just a simple question that spoke to my logical side.

Why use something that is so hotly debated, when there are products uniquely designed to clean coated optics, that not only yield excellent results, they are safe, inexpensive and readily available? :question:

Also a warning against "canned air" I found. It's safe to use in most applications, but there are pitfalls that can ruin your optics, especially on Fluorite lenses. It can also condense moisture from the air (depending on your humidity level) and deposit it on your lens in the form of a hard opaque stain. YMMV.

I found an excellent primer on cleaning optics at the "Company 7" web site. A company well known for their relentless pursuit of quality. Click Here

Good luck. :)


#30 iam1ru12


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Posted 09 July 2013 - 10:38 PM

I'll chime in here as well. I've used Dr. Clay's method (http://www.arksky.org/asoclean.htm) as well with much success on my personal scopes, my club's loaner telescops and a cleaning session we ran with the NC State Physics Department (their 12 8" SCTs used for astronomy labs were in rather poor shape).

Dr. Clay does recommend using Windex but I want to make sure everyone reading this thread is aware of exactly how it is to be used. We're not talking about grabbing a bottle from your cleaning supplies and spraying it right on your optics. We're talking about filtering the Windex then diluting it. It's one ounce Windex combined with 1.5 ounces of "pure" isopropyl alcohol and 2 drops of Kodak PhotoFlo solution. This 2.5 ounce solution is mixed with 12 ounces of distilled water. It is this final solution, that contains some filtered Windex, that is applied to your pure cotton / synthetic cotton pads which then lightly used on your optics.


#31 Stacy


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Posted 11 July 2013 - 03:10 PM

From Celestron,

Dear Stacy,

Thank you for contacting Celestron Technical Services. We spoke a few days ago and you mentioned that on a forum it was mentioned you can use Windex to clean your corrector. Can you provide us with the forum that indicates the information? Windex is not used to clean the corrector. See links from our knowledgebase.



Thank you

Celestron Technical Support

Like I said, fairly non-committal, except they do not recommend it.

#32 dougvolfan


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Posted 14 September 2013 - 11:47 AM

i have tried to clean the corrector plate with the cloths that come with eps. Unfortunately I did rub in circles in some place and applied a little pressure. Last night I could not focus any stars. Did I screw up the corrective lens or maybe bump the outer cover of the secondary mirror cover? Also if the corrector plate is screwed up can celestron put on another?

#33 Brian Risley

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Posted 14 September 2013 - 12:20 PM

Do you have any added accessories that might have screws extending into the mirror path? It takes a lot more than cleaning to make you not able to focus. (I have a C-8 with a cracked corrector and a primary mirror where sections of the coating are missing. It still comes to focus and presents a decent image! ) Look inside along the edge of the mirror and see if any screws are close to the mirror. If there are, then back them out until they clear the mirror. (Don't remove any flush mounted screws on the rear cell, just the round headed ones.) Was this an ota removed from a fork mount? If so, the screws that were holding the fork should be replaced with much shorter ones!
Don't force focus, if you have a screw hitting, then you could damage the mirror.

Did you remove the corrector or secondary or add something like Bob's Knobs or in any way mess with the screws holding the secondary? If so you could be way out of collimation.
You need to look up collimating a C-8 and check the initial rough alignment from the front (about 10 feet away, see if the reflections are concentric. If they aren't then we need to have some idea about what you have recently done to the scope to figure out where to start.
If you have a club in your area, see if someone there is experienced with a C-8 and collimation.

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