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Cleaning of Corrector Plate CPC EdgeHD 1100

cassegrain Celestron DIY optics SCT
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#1 arshadwm

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Posted 02 December 2020 - 10:27 AM

Hello. I cleaned the corrector plate with Distilled water isopropyl alcohol and detergent solution 

 

after that I finally cleaned by Lens Cleaner. 
 

now I can see some very tiny dots all over the corrector plate. I didn’t see any problem while observing the objects however I am bit worried with these tiny dots. Are these normal coating or something went wrong ? Please advise and see the below yputube video 

 

https://youtu.be/IuEyEdNygUI

 

 

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#2 Whichwayisnorth

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Posted 02 December 2020 - 01:09 PM

Doc Clay has a kit  that has worked great for me.

 

I am actually out of the cleaner spray and need more but don't need it at the moment.

 

Anyways, following his directions mine always come out super clean.

 

I've also just used windex and plain white kleenex.  

 

Dabbing and not wiping is key.  

 

If you have hard water spots they can be a pain to get off.  This is where I take a step back and wait for someone else to offer suggestions.  I don't want to be the person that gives you bad advice that ruins your gear.



#3 KerryR

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Posted 02 December 2020 - 01:12 PM

I don't know what the dots are, or if that's 'normal' or not. However, shining a flashlight into/onto just about any commercial mass market optics will reveal all manner of spooky stuff, to the point where the practice is, it's said, to be avoided. I'll use a flashlight to scrutinize my work when I clean optics, but I take what I see with a grain of salt. As long as things look clear and 'dark' from the front under normal room lighting, and you're not seeing a glowing halo around bright targets under the stars, everything is probably fine.


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#4 alphatripleplus

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Posted 02 December 2020 - 02:09 PM

I've also tried original Windex and unscented kleenex with no adverse effects as far I can tell.



#5 KerryR

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Posted 02 December 2020 - 02:39 PM

I've read here on CN of some instances where anti-reflection coating pitting, in the form of little dots and cirlces, has been observed on some scopes, usually SCT corrector plates, that are subjected to repeated heavy dewing in humid urban locations, where the air/fog/dew can be comparatively acidic courtesy of air pollution; the 'acid fog', over time, can, apparently, etch the glass overcoats... or so it's said. Anyway, if you live somewhere where that's a possibility, consider adding active (heated) dew prevention if you haven't already.



#6 arshadwm

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Posted 02 December 2020 - 03:15 PM

@soyuz. Thank You however how to remove these tiny spots and I leave them as it is .



#7 arshadwm

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Posted 06 December 2020 - 08:00 AM

Thank You all 



#8 Michael Harris

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Posted 14 December 2020 - 08:59 PM

Don’t worry about little spots on the inside, they don't interfere with the view. I have taken off corrector plates to clean them when there were serious problems like mold spots, it’s a little nerve-wracking but not difficult. But only if the spots are very large, otherwise they disappear into the background and are not close enough to the focal plane to interfere with the image.



#9 thesubwaypusher

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Posted 18 December 2020 - 08:32 PM

Hi A:

 

Whenever you clean optics you degrade them. 

 

The spots you see are nothing to worry about. Dew residue, pollen, whatever they are we all have them. One of the cardinal rules of owning a telescope is to not analyze the optics because you will find junk that you do not want to find. I observe under NYC skies and I swear I don't recall when the last time I cleaned a corrector, meniscus or objective. If you can't see problems in the dark, everything is fine. Just enjoy. Don't make things worse with any type of pressure. Although the coatings are resilient, they do have their limits.

 

Good luck, Chris

 

 



#10 Oort Cloud

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Posted 20 December 2020 - 10:12 PM

I don't think that looks like it needs to be cleaned yet. I didn't have good results when I tried alcohol/water/dish soap, so I removed the corrector and used dish soap in my hands and tap water to clean it, with a final rinse using distilled water. Blew off most remaining water with air bulb and then used tissues to finish drying. Cleanest it's been since it was new. Just be sure to index the corrector plate somehow so you can make sure it goes back on in the same orientation if you remove it.

#11 arshadwm

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Posted 21 December 2020 - 07:59 AM

Thank You 




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