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cleaning a 1-meter CDK mirror

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#1 prefetch

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Posted 18 October 2020 - 01:29 PM

i spent yesterday cleaning this filthy mirror in my planewave CDK 1000 and i thought i'd share some images.

 

here's how it started out.  lots of dust and water stains.

dSc1jSX.jpg

 

i sprayed it with a spray bottle filled with soapy distilled water, and then laid out viva paper towels, then sprayed those with distilled water.  notice the beach towels stuffed in the sides to catch water.

 

FyVBc4K.jpg

 

i then removed the wet paper towels and repeated this process.

 

next i sprayed it with distilled water, then with 91% alcohol and let it dry.  the images below show water.  i don't have an image of the alcohol, but it looks different - there are no beads with the alcohol, it just looks wet.

 

fmGksgT.jpg

 

y5H71hd.jpg

 

 

after i came back an hour later, i shined a super bright flashlight on it and noticed some streaks and things.  i used alcohol and microfiber towel and gently rubbed away all of streaks and marks.  

 

and here it is all nice and clean.  next step was to clean the tertiary mirror (the secondary was pretty clean already.)

UCNJuGa.png

 

anyway, that's it.  i was scared to death to do this, but it wasn't too bad at all.  now i'm confident enough to do it again maybe next year when i'm sure to screw it up due to my overconfidence.  grin.gif


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#2 elwaine

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Posted 18 October 2020 - 03:14 PM

Nice job. Thanks for sharing those photos.


Edited by elwaine, 18 October 2020 - 03:17 PM.


#3 junomike

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Posted 18 October 2020 - 03:20 PM

Looks great.  I wonder if you can do a large Newt the same way (looks easier and less risky than taking out the mirror).


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#4 alphatripleplus

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Posted 18 October 2020 - 04:36 PM

Just curious how long it took to get dirty enough to necessitate the thorough cleaning?



#5 prefetch

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Posted 19 October 2020 - 02:43 AM

Just curious how long it took to get dirty enough to necessitate the thorough cleaning?

almost 2 years.  there was a lot of construction and excavation at the site that first year which created a lot of dust in the air, plus the observatory dome leaked and the telescope would get water leaking onto it.  this combination of factors made for an unusually dirty mirror.


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#6 Codbear

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Posted 19 October 2020 - 08:35 PM

Looks great.  I wonder if you can do a large Newt the same way (looks easier and less risky than taking out the mirror).

I would think there wouldn't be any difference, other than not having to worry about the liquid going through the central mirror hole.

 

With my muscle disease it is impossible for me to take my 24" mirror out and clean it using a "traditional" method, but this actually looks doable.

 

Care would need to be taken to make sure water doesn't get down into the GoTo electronics underneath the mirror, but a piece of cardboard cut to the base dimensions, covered with a couple of layers of plastic wrap and taped to the edges of the telescope base and slightly angled to drain any liquid that might find its way below the mirror should do the trick.



#7 alphatripleplus

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Posted 20 October 2020 - 07:38 AM

almost 2 years.  there was a lot of construction and excavation at the site that first year which created a lot of dust in the air, plus the observatory dome leaked and the telescope would get water leaking onto it.  this combination of factors made for an unusually dirty mirror.

Okay, that makes sense. Hopefully, you will not have to do it that often in the future if those factors don't come into play again.



#8 cmaier

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Posted 21 October 2020 - 10:34 AM

So just having  the wet paper towels sit twice on the mirror for some time  picked up all the bits of dust and stuff?




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