Re: ATM Silver coatings

[Bratislav Curcic <epabcc@epa.ericsson.se>]

Don Morrison wrote :

> I have found that the surfaces are extraodinatly delicate, scratching at
> only a suggestion of contact, and, this is what causes me the most concern,
> they have an uneven, smoky or cloudy appearance in strong light. Is this
> normal or have I  got dud coatings?

One thing is for sure - coatings have to look just as one expects them -
uniform, bright and sqeaky clean. 'Smoky and cloudy' will be painfully
visible as scatter at the eyepiece, and not just on bright objects.
Are you sure that mirrors are well polished ?

About hardness - I'm not sure how the company in question does 'protecting'
but I thought that this has to either be Quartz overcoat (very hard) or
MgF2 (not as hard, but still withstands reasonable handling).

Can you tell me which is the company in question (privately, please) ?
BTW, I'm in Melbourne, so it does have practical value to me. 
The only other company I know that does silver in Oz is in Qeeensland
(Brisbane I think). Can't remember the name though.

Bratislav