[ATM] Quartz blanks

[Mike Lockwood <melockwo@uiuc.edu>]

Hi,

Just wondering if anyone out there had a source for larger quartz 
blanks that they recommended.

I may be looking for a blank or two in the 20" range, ~1.25" thick. 
The use is an astrograph primary (F/3) for a friend, and possibly a 
Cass. primary for myself.

A pyrex mirror has a large focus shift with changing temperature, so 
we are investigating lower-expansion substrates.  If the price is 
astronomical we'll stick with Pyrex.

One company already declined to quote prices, saying they would not be 
competitive.

Also, if anyone is interested in a 20" F/3-generated blank, 1.25" 
thick in Pyrex or Quartz, let me know.  I will likely be putting 
together an order.

You can reply off list if you wish.

	Thanks,

	Mike Lockwood


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