Hi Mike that is a very neatly written article and it's easy to follow, the mirror cleaning subject is not always the easiest one to present verbally or otherwise, and everyone has slightly different ideas on how to do it exactly but you have presented the essentials in a easy to follow way, i am sure it will be popular with many people searching and browsing for help on the subject.
Thumbs up
Yep, good article. I pretty much followed that method when a fellow IIS Lostock 2006 attendee asked me about cleaning his (overcoated) Newtonian mirror, so I used the kitchen sink in the main house to do it, thanks to the overcoat protecting the underlying aluminium, despite the mirror being quite dirty, after cleaning it was like new.
Scott
I do pretty much the same with the exception of a warm rinse of the mirror from the tap to gently flush away loose crud before filling the sink. Loose dust and dirt particles get removed from the equation, leaving mostly solidified softer gunk left.
The less crud that ends up in the soapy bath, the less danger there is of inadvertent scratching of the mirrors coat.
If that is your mirror featured there, i think standing on it with such dirty looking workboots is a bit of a rough practice, surely you could stand beside the mirror while delicately prising the foreign bodies of it with the featured cleansing device
A very informative article,and many thanks for your efforts,
Might I suggest,before replacing the mirror, A light going over, with very low pressure compressed air,may remove any particles,that may remain from the paper towell.
I have used paper towell for final cleaning my Binoculars,and Allways end up with small particles,on the lenses.
I use a small air Compressor,with an air nozzle,to get rid of it.
i'd keep my optics away from compressors as they also blow water/particles (often with rust and junk from inside the tank) if you wanna see whats coming out of your compressor, turn it on and hold the nozzle close to a piece of glass, you'll see spots of nice brown water forming
I wouldn't even use the canned variety - yes you can shake them up but at the start they still blow some liquid out, and if you don't hold them perfectly upright they'll blow liquid out.
Best to use a normal hand-pumped blower that you can get from chemists, camera shops, etc.
true, but there are canned products that dont use hydrocarbons as the propellant.
apparently the best way to clean a mirror (that most of us wouldnt have access to) is using carbon dioxide (something like a fire extinguisher), the dust and junk on the surface freezes and blows/rolls off, no touching of the optical surface in any way required
Actually, believe it not, they use detergent and sponges and mops.. Yes Mops !. Then hose it off.
Here is how the do the 200inch Mt Polamar telescope http://hpwren.ucsd.edu/news/20061019/
Hi Mike. A good article, basically the same system I follow (I even use the exact brand of demineralised water in your photo).
A couple of suggestions:
- The best water to use is "demineralised", not just distilled. Demineralised will do a better job and evaporate without leaving any residue. (Since you're already using demineralised water this is just a slight correction in terminology).
- New mirrors should be left for at least 3 months before cleaning them. I've been told (and I think it's true) that newly coated mirrors have an overcoat of SiO (silicon monoxide) which over time will oxidise into SiO2 (quartz). Even though the overcoat may be advertised as "quartz" it really starts as the much softer (and porous) SiO which should not be exposed to cleaning.
Mike's process is pretty sound, but I'd be more inclined to use a pure detergent than dishwashing detergent. Most dishwashing detergents have lanolin or a similar oil added, and this can leave residues. So something like Kodak Photo-flo or Ilford Ilfotol (so called "wetting agents") would be preferable. Very dilute Teepol (a Shell product) would also work.
) has kindly written a how-to article titled Cleaning the Mirrors of a Newtonian Telescope.
