Primary mirror cleaning

[N3ptune]

I found this second hand mirror for almost nothing and I want to do a cleaning practice on it before I do it on my telescope mirrors. If I can get it clean without scratches, I might try to wash it a few more time, abuse it a little bit just to see how strong  the mirror coating is. (Looks like a fun project to me)

I could share the pictures here if some are interested in seeing this experience.

(:

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UPDATE 2016-06-18 - My first test and observations

https://drive.google.com/file/d/0B0OZ0oXfzDlFVEQzNmtsdlFUVXc/view?usp=sharing

[Jimtheslim]

Yes, give it a good clean and see if you think you would regret it with your actual telescope mirror. I did a similar thing with my old star diagonal and came to the conclusion that it was a lot of hassle for nothing but would be interested to see what happens with a big primary

[Ally8446]

Very interested in the outcome. 

Ally

[DHEB]

Very interested in the results as well as in your methods. How are you planning to do it?

FWIW in the book "Astronomy Hacks" the authors recommend just tap water. If the mirror is too dirty, they suggest submerging it for several hours in slighty warm water with just a tiny drop of mild detergent, and then rinsing the mirror at an angle under a moderate water stream from the tap. After that the mirror should be left to drain and dry at an angle. They suggest never touching the mirror, except for very slight touches with a paper nap to suck the last minute drops of water that won't drain. I have never done this but I believe it is not harmful.

Good luck!

[Timebandit]

Hello. Owwwww ?  I would be very interested in the results of this.  The times I have been tempted to give my mirror a gentle little clean just to make it sparkle(as It must give better performance clean than dirty by all logic ??). From what I have seen and read there seems to be a big anti clean thought in existence. I have heard the best way to clean a mirror is a bit of good quality washing up liquid in a bowel of warm water then let it soak for a while, then gently wipe over the mirror surface with some special medical type of cotton wool(I have even read somewhere that normal cotton wool scratches the mirror?) What I would be interested in is how are you going to see if your preferred method first works as It supposed to, as surely you will have to examine the surface with some type of magnification aid prior and after cleaning to pick up minute scratches . as even minute scratches I understand this can damage the mirror surface after incorrect cleaning method and effect the performance?.  To me seeing I have a frac also I try to simply the clean or not to clean debate by comparison to a house glass window. If your house  window glass is dirty then it is obvious to me it effects the quality of the image you can see through it, but give the glass window a good clean and the image you can see through the glass window improves considerably . My reasoning then this must in all logic apply to telescope mirrors and frac glass lenses. There must be a point in time a unclean mirror or frac lense effects the image to a detrimental degree that cleaning is needed(remember all of us want the best possible from our scopes and we are talking about fine image detail over vast distances we are attempting to view and capture) . Therefore I feel this is a very important and interesting topic to hopefully we can answer the clean or not to clean debate. I would certainly like to see the responses☺

[brantuk]

Detergent can embody a whole world of different substances - don't use it - just a couple of drops of pure soap is more than enough (e.g. Fairy Liquid is pure soap). Here's a link for mirror cleaning:

 

[spaceboy]

I think be it cleaning mirrors, optics or even collimation it's all just a case of self confidence.

Sky-watcher mirrors are coated with silicon dioxide so as long as your not cleaning the mirror with a brillo pad you shouldn't cause ill effects from giving your mirror a flush under a warm shower.

[N3ptune]

(; It will be done the following days. The dust on the mirror right now is a commercial grade dust, the mirror comes from the telescope workshop, it looks heavy and artificial.

I will follow Brantuk's procedure has in the video for the first wash, has discussed in another thread from a few months ago which was interesting also but unfortunately, didn't end happily.

I will also get the fairy Liquid, it's possible to order it on Amazon. Has for the towel, it's going to be the Zeiss microfibre cloth has the address bellow, they are really soft.

http://www.zeiss.ca/camera-lenses/en_ca/camera_lenses/accessories/cleaning_products.html  

If the first clean up is a success, for the second wash, I want to scrub the surface with my bare hand, directly touching the mirror. Some say it can be done without problems but I want to see it to believe it.

spaceboy

That's good to know about the Silicon dioxide, I am glad to ear that my good mirror has an extra protection, to help me in the process of cleaning it someday. (:

[gls]

I was told by the people at my astronomy club that you should give it the final rinse with distilled water because it doesn't contain any impurities and won't leave any stains on the mirror. Not sure if it makes a difference but this is what I did.

 

I was also advised to use a brand new sink bowl so there would be no residues left in it.

 

Sorry if the link mentioned this, I didn't watch it.

[N3ptune]

I did an experiment with pictures.. I can't say if it's exactly a success but the mirror is quite clean now. I have a PDF of this, (Actually not yet)

GLS

Yep, they talk about de distilled water in the video. Has for a new sink bowl, honestly I trust a clean bowl I have here, it's not a bad idea to get a new one either.

 

[Dave In Vermont]

I'm glad distilled-water was recommended. Considering the stains tap-water leaves behind in a toilet-bowl, one certainly want that on a mirror!

Here's a pdf. from Doc Clay - most famous fixer and super-tuning of SCT's and their relatives in the USA - which I also gave to another person(s) just yesterday.

ASO fine optics CLEANING SYSTEM - Part I & II.pdf

"When it rains - it pours."

Dave

[N3ptune]

Those are my observations during he process of cleaning the 102mm. I am not sure if the result is satisfying or not, if this mirror could be used, I think it can.

https://drive.google.com/file/d/0B0OZ0oXfzDlFVEQzNmtsdlFUVXc/view?usp=sharing

[jetstream]

Interesting technique!

These days I follow Mike Lockwoods cleaning ideas, fairly close anyway. For the first step I use a pump sprayer with a weak dishsoap solution and mist the mirror with it, the soap  will "lube" any grit on the surface before rinsing off. I then tip the mirror up and mist the same solution on until it runs off easily.

Then, depending on the cleanliness of the surface I will use another pump sprayer and "mist" (rinse) the mirror again with RO or distilled.Then back to step1 , then2 again.

Lockwood and some others don't like the idea of soaking for very long... coatings issues potentially.

You might try pure acetone ( not nail polish remover) on the centre spot glue and the clip residue. Very carefully and at your own risk- no rubbing just dabbing or blotting.

http://www.loptics.com/articles/mirrorcare/mirrorcare.html

 

[gls]

7 hours ago, N3ptune said:

GLS

Yep, they talk about de distilled water in the video. Has for a new sink bowl, honestly I trust a clean bowl I have here, it's not a bad idea to get a new one either.

I just thought I mention the distilled water because nobody else did and not everyone who reads this thread might watch the video. 

 

I think you'd get away without using a brand new sink bowl too, as long as you haven't just finished washing up a fry up or a curry, but, for the price they cost, you've got nothing to lose. 

[Stu]

I use RO water which you can pick up very cheaply from any aquarium

[N3ptune]

Stu

Great tip, you go to the aquarium (aquarium store?) with a container and they fill it up with RO for you or they sell sealed gallons of it directly ? How much does it costs ?

GLS

I went to the dollar store to buy a container and they didn't had anything the right size ... what bad luck, that's why I used one I already had this time.   For my 203 mm am going to get a new one.

 

[Stu]

14 minutes ago, N3ptune said:

Stu

Great tip, you go to the aquarium (aquarium store?) with a container and they fill it up with RO for you or they sell sealed gallons of it directly ? How much does it costs ?

GLS

I went to the dollar store to buy a container and they didn't had anything the right size ... what bad luck, that's why I used one I already had this time.   For my 203 mm am going to get a new one.

 

Pretty sure they sold me a container first time I went but they will fill up a container for you if you have one already. Only cost a few pounds at most if I remember correctly.

[N3ptune]

Stu

Ok ok it really inexpensive.

Jetstream

Thanks for the link I found interesting thing in there. I think the pump sprayer is a good idea only if the mirror is not too dirty and cleaned periodically to prevent accumulation of a film. I don't think it's possible to remove the sticky dust like the one that what was on my 102mm, without touching it with something..

--> I am going to test the alcohol and acetone on my mirror and see, just for fun, i feel Acetone could do more harm then good but I bought the mirror just for that so.