Mirror Cleaning

[+Bino-viewer]

Hello guys.

 

I'm sure this topic has been covered somewhere in the past before.

 

I'm getting close to the point where its time to clean my primary for the first time.

Now i'm sure there's some of you who will say.... "don't do it" ,  "leave it alone" ,  "it won't matter if it's a bit dusty"  etc, etc.

 

Looking at my mirror though, i get the impression it's not been cleaned since it left the factory.

Thats nearly 2 years ago, and looking at it, its visibly dusty. Not just a little bit. Quite a lot.

There's a black speck of something on it, and also what appears to be quite a few carpet fibres. (It was stored indoors in a carpeted room by the original owner...)

 

So, its time for a clean.

I'm not taking this lightly. I've trawled YouTube and watched several cleaning video's.

This includes Dion's. (Astronomy shed)

However, i'm not going to follow Dion's as i dont want to touch the mirror with my fingers.

 

This is the video demo i shall be working to.....

 

 

Now, before i start i shall be sourcing some medical grade Distilled water, and the 'BP' cotton wool that Dion recommends.

And of course i will be ultra careful the whole way through.

It would be a costly bit of glass to replace, and i am a bit on the clumsy side ! 

 

Have any of you guys got any tips ? 

How often should i need to clean my mirror ?

I'm reckoning it will be a once a year sort of thing. What do you think ? 

 

 

[Brantuk]

That's the Steppenwolf mirror cleaning video (Steve who wrote Making Every Photon Count). It's the guide I followed and is very good. You shouldn't need to clean it till the dust is a quarter inch thick and seriously inhibiting the views. But I know you're gonna go ahead and do it like we all did once. Mark the tube and mirror positions as you disassemble the scope so you know exactly how to put it back together.

 

After blowing off any loose dust - give the mirror a good soaking first - run under a luke warm tap for 20 mins. When cleaning with the cotton wool - don't press - wipe under just the weight of the wool itself just two wipes per swab one side then the other. Drag it from the center outwards and turn the mirror as you go. After rinsing stand to dry - wick off any excess with the tip of a folded paper napkin.

 

Don't pinch the mirror when screwing it back in it's clips or you'll get deformed stars.

Good luck

[Doc]

Basically what Kim says.

 

I kept my mirror in it's cell. Ok if you have no electrics on the back cell.

 

Only use the cotton wool once just in case it's picked up any debris you don't want to scratch the mirror. Wipe from the centre outwards.

 

After it has been cleaned stand upright and pour Isopropyl alcohol over mirror this will then evaporate leaving no streaks and a gleaming mirror.                          

[+Bino-viewer]

Thanks for the tips.

 

Isopropyl alcohol ?

I've not seen that being used ? 

I thought that was what the distilled water was for ; to leave no streaks residues etc....?

i could give it a go. Amazon list it for £5 for a 500ml bottle.

 

Is it re-usable ? Or drinkable even...? 

[Doc]

I didn't reuse mine but I see no reason why you cannot.

 

It just leaves a very nice unstreaked mirror. Maybe distilled water also leaves an unstreaked mirror, I don't know as I have never tried it.

 

I have tried washing the mirror with just luke warm water and washing up liquid and rinsing off with tap water and that does leave streaks. 

[Brantuk]

I used tap water with a little soap to clean it - rinsed off with clear tap water - rinsed that off with distilled water to remove impurities - then a quick splash of IPA to leave it unstreaked. Maybe I was little ott.....? lol

[BAZ]

When you decide to take the cell out, do it with the secondary end down on some nice soft carpet and the primary cell upright. This makes getting it out easier as the tube wants to collapse on itself if you do it on it's side. Use some insulating tape to mark the cell and the tube, so the cell goes back right where it came from. This makes it a shed load easier to get back in as well.

I have only used the bog basic green washing up liquid, this is to have no fragrances or added whatever properties, just the detergent. I rinsed the mirror with the shower in luke warm water, then let it soak for half an hour in like warm water with a couple of drops of washing up liquid in it. Then rinse with luke warm water in the shower again and finally rinse with de-ionised water and as Kim said, dry the drops that are left off with a tip off kitchen paper.

I took my mirror out of the cell, but again marked both with a sharpie, (on the side of the mirror and cell) so that it is put back exactly where it came from. I then used baking sheet (the brown thin slippy stuff) as a feeler gauge when putting the mirror clips back on. the mirror should be free to rotate when you have finished. If you get it too tight you will get triangular shaped stars. I have done this and it's really disheartening when you have a good clear night and a stuffed scope you know you have to take to bits again.

 

Here's mine before!

 

 

And after.

 

 

Edited December 11, 2015 by BAZ

[catman161]

Yeah as above rob. I did exactly as they have already said. I followed Dion's (astronomy shed) video on Newtonian mirror cleaning. This was mine before:

This was it after:

[Daz Type-R]

When we did mine it was soaked in a bowl of warm water with bog standard plain Fairy washing up liquid, rinsed with warm water and wiped from centre to outside with surgical cotton wool, using 1 peace per wipe, rinsed again and then rinsed with de-ionised water.  Left it propped up in the sink and it came out perfect.  Here are my before and after picks.....

 

 

 

Only reason I cleaned mine was the primary was out to flock the OTA, if I wasn't doing that I wouldn't of bothered, you don't need squeaky clean mirrors.

 

Ive had the scope nearly 5 years, it's been cleaned once.

 

[+Bino-viewer]

Thankyou chaps for your tips.

 

All your 'before & after' pictures prove to me this is a job that is genuinely worth doing.

I've ordered some surgical cotton wool and distilled water which should be with me in a few days. IPA as well.

 

One little point. Distilled water & de-ionised are not the same thing.

 

Also.......what about the secondary ? Does this need a periodic clean as well ?

 

Btw....i've really enjoyed the modding process so far.

And i may have a tracking platform sooner than i think.

There's one going one UKABS and i've made the chap 'an offer' which he's accepted 

[Brantuk]

The secondary is face down (at 45 degs) and doesn't attract as much dust as the primary which is face up to the elements.

 

(So it's a "no" basically)

[+Bino-viewer]

Thanks kim. That makes sense.

My 'Rocket bulb' shifted most of the dust off there anyway.

[Brantuk]

Yup - that'll be more than enough for a secondary

[BAZ]

It looks like Felix got a crop of spuds off his mirror, that did need a clean.

[Doc]

I left mine till it was like this before I done mine 

 

 

[+Bino-viewer]

Crikey Mick 

That is a dirty mirror !!

[BAZ]

That stain is where he fried an egg on it!

[+Bino-viewer]

I wouldn't be able to sleep at night if my mirror was like that.

 

I'm now thinking mirror cleaning isn't a job to be scared of.

Just prepare well and follow the online guides, and the results will show for themselves.

Darren, Martyn and Felix's end results are proof.

Obviously great care is needed, but i often wonder why all the forums advise against cleaning at all ?

The coatings on these mirrors are actually very tough as well (in most cases)

 

I do recall though reading a 'Cloudy nights' post re mirror cleaning a few years ago where this chap had actually

put his mirror in the dishwasher and ran a full cycle 

On that occasion the result was a nice shiny piece of glass.....minus the coatings ! 

 

 

 

[Daz Type-R]

The reasons we are told not to clean them is because they can be absolutely filthy and it does not degrade the view.  You could quit easily make things worse by scratching the mirror or removing the coatings, as Micks mirror shows, he was observing with that.

 

Had I not been flocking my OTA I would not of cleaned it.

 

The views through my scope were better after the flocking and the cleaning but I bet the clean mirror contributed nothing, it was the flocking that improved the contrast.

 

Like you said Rob, nothing to be scared of but I doubt it really needs cleaning.

[Doc]

Just like to point out it's not my mirror.

But I have had a few mirrors that are at least half as bad as that one.

One of them took over three hours of soaking in a bath to remove all the crud.

Edited December 12, 2015 by Doc

[catman161]

It looks like Felix got a crop of spuds off his mirror, that did need a clean. [emoji3]

It really did need a good clean Martyn! I miss my old 200P. It gave me some beautiful views and some OK planetary images. It resides in Fondofchips obsy nowadays [emoji106]?