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Skywatcher Dob mirror cleaning: step-by-step (visual) instructions ?

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#1 fromEarth

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Posted 14 December 2018 - 03:34 PM

Hi, 

 

I bought my 12'' collapsible SkyWatcher dob after watching movie {Interstellar} in 2014. Now its primary mirror is a little bit dusty and I am thinking of mirror cleaning during this winter season.  

 

 

[1] Option_1: blowing dust?

 

Actually the mirror's condition is not that bad at all, but I can see a (very) thin layer of dust on the mirror. Is it OK to use a strong electrical fan or blower to remove dust? Is there any possibility that some small particles in the blower's strong wind stream can damage the mirror's coating? 

 

 

[2] Option_2: mirror cleaning?

 

When I ordered my scope from Amazon, I received an pre-assembled tube, so I have no idea how to assemble/disassemble mirror (primary and secondary) parts. I watched several youtube video clips, but they did not explain how to do it. Is there any visual (and detailed) instructions showing assembly/disassembly steps for this specific SW dob? 

 

 

fromEarth


Edited by fromEarth, 14 December 2018 - 03:35 PM.


#2 StarBurger

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Posted 14 December 2018 - 04:03 PM

Hi fromEarth.

I would not touch the mirror at all. Dust on the mirror is a fact of life and unless severe (like it was left uncovered for years near a cement plant) it is not worth cleaning off yet by any method.

One rule of reflectors is NEVER LOOK AT YOUR MIRROR WITH A STRONG LIGHT! There lie demons!

The mirror always looks MUCH worse than it is.

At some point in time mirror cleaning may be desirable only, much like washing your car followed by a good wax polish (but not your mirror!) but it will not improve the performance much.

Even if you did clean your mirror it is doubtful you would visually notice much difference anyway.

So-don't remove the mirror, don't clean it  and don't look at it, just look in it and enjoy the views.

 

 



#3 Jon Isaacs

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Posted 15 December 2018 - 06:53 AM

There comes a time when it is necessary to clean a mirror.  It is something you need to do carefully but it is not something to be afraid of.  This is the technique I use and have used for the past 6 or 7 years.  It is very effective in getting the mirror clean and very gentle on the mirror.

 

https://www.youtube....8xFnXFVGQ&t=29s

 

Jon


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#4 Asbytec

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Posted 15 December 2018 - 10:01 PM

Is there any visual (and detailed) instructions showing assembly/disassembly steps for this specific SW dob? 

 

 

fromEarth

First, I agree with Jon on cleaning. It's not complicated.

 

As for disassembly, I guess the best way is to just see how it's put together. Looking at pictures it seems the mirror cell is similar to mine and pretty common these days. The primary mirror cell is often integrated into the bottom end of the tube itself as a single unit rather than being a separate cell. There are very likely screws that hold it in place, that's how it's assembled. You can see them in this picture.

 

https://www.highpoin...ynscan_rear.jpg

 

Be careful to support the upper end of the OTA, first, because once the weight is removed from the back the upper tube will instantly nose dive into something. Remove any screws and pull the mirror cell away from the bottom of the OTA. The thin metal tube will likely distort a bit once the cell is removed, so you may have to finagle the tube shape when you reinstall the mirror cell. No biggie. 



#5 sparksinspace

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Posted 16 December 2018 - 01:03 AM

https://www.cloudyni... is dirty dirty79-when-is-dirty-dirty/

 

This was how dirty mine was. and how I went about it. It is fairly straight forward to do and you will learn more about your scope if you do it.  




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