Re: ATM Cheap Astrositall

[astillma@nit.AirTouch.COM (Anthony Stillman)]

Lance,

I've ground and polished one quartz mirror, one was enough.  Compaired to 
Pyrex it was a dream to polish, but a pain to grind.  It seems, I was told
this by Gerry Logan, the harder the material the easier it is to polish.
This is due to less sub-surface damage and smaller pits and scratches
left from the fine grinding stage.  

I've not worked with Zerodur yet, I plan to soon as I picked up a six
inch blank at Riverside.  I'm told that Zerodur is harder than Pyrex 
but softer than Quartz.  So I expect a six inch will not be that difficult.

Incidently, I am told (Kevin Medlock) that some Zerodur, depending on how
it was made can be worse than plate glass.  I've got my fingers crossed.

Anthony