Re: [ATM] newbie question

[Jarvis Krumbein <jkoptic@juno.com>]

Nigel, the easy way is to use a glass (plate, Pyrex etc.) substrate and
coat it with a highly reflective metal (aluminum, silver etc.) surface. 
While there is some labor (can be quite a lot actually) the method is
fairly simple and well understood.  People have been trying to come up
with an alternative for many years without success and we eventually go
back to glass which we know works.  The liquid metal (Mercury) mirror has
been used for a couple of fairly large telescopes and as long as you can
eliminate vibration and only want to look straight up works fine.

Jarvis Krumbein
jkoptic@juno.com

On Thu, 13 Sep 2007 13:55:56 +1000 Nigel Weeks <nweeks@prism9.com>
writes:
> 
> A liquid metal mirror that's being spun, has a paraboloid shape, 
> yeah?
> 
> Aluminium, or even polycarbonate plastics, could be molten, spun, 
> then
> cooled and annealed.
> 
> Ah, uneven cooling, distortion when mounting, etc.
> 
> Damn. No easy way...
> 
> N
> 
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> 
> 
 
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