Re: ATM Thanks for responce

[Andy Saulietis <iss@pvtnetworks.net>]

David T writes,

>    I was surprised that my question regarding the durability of enhanced as
>a opposed to standard coatings didn't receive more response but I sent it in
>HTML format so some of you my have deleted it. I would like to ask again.
>Are there any enhanced coatings that match or come close to the 10 year life
>span of standard aluminum coatings.

Our experience with enhanced silver coatings at NASA in the 70's was not
good, these lasted only a few months & were most likely damaged by
exposure to sulfur dioxide. We switched to enhanced aluminum & kept
the scope purged with dry filtered air at slight positive pressure; these
coatings lasted 15+ years.

Beral can also be long lasting, I mothballed a 16" Cass set with
Aluminum primary & tertiary, Beral secondary, the Al coatings are
shot but the beral still looks good after 10+ years. This
scope is being resurrected this summer.

The biggest killer of coatings is water condensation, especially wrapping
it up while still wet.




Andy Saulietis
ISS Enterprises
39 Silver Fox Trail
Mayhill NM 88339
505-687-3067 voice
505-687-3021 fax, call voice or e-mail to set up
e-mail: iss@pvtnetworks.net