Re: ATM Lenses from natural quartz

["B. Pepin" <atmjedit@conceptsnet.com>]

Greetings Dominic,

Precent for quartz? Oh yes indeed. The first telescope lenses on record as
'made to order' were ground in the Netherlands using natural quartz, by
optician Hans Lipperhey in 1608-09. 19th C. French maker Cauchoix used
quartz in sizes up to 4 inches (when he could get it that large). Results
were good.

Recently, however, the synthetic stuff has taken over for specialized lenses
and flats, its more homogeneous.

Barlow




----- Original Message -----
From: Bill Marriott <btk@pacbell.net>
To: Dominic-Luc Webb molmed <Dominic.Luc-Webb@molmed.ki.se>; <atm@shore.net>
Sent: Thursday, April 26, 2001 8:06 AM
Subject: Re: ATM Lenses from natural quartz


>
> Dominic-Luc Webb molmed wrote:
> >
> Dominic
>
> > Does anyone here know (maybe a reference) that
> > naturally occuring quartz can be used to make optics
> > and any ideas as to how suitable it is in making high > quality lenses
(i.e., UV
> > transmitting, etc)?
> >
> > Dominic
>
> Before the advent of syntheticly grown crystal quartz, natural crystal
> was used for both optics and piezo electric stuff. During WWII, having
> difficulties getting high quality crystal from Argentina, the Germans
> developed the techniques for growing crystals (So I've been told
> anyway). I suspect that the yield of optical grade material was fairly
> low, as compared to "electronic grade", as well as issues of orientation
> of the lattice probably made it difficult to work with...
>
> These days, for UV work, high grade optical fused silica preforms
> well....
>
> Bill Marriott
> http://www.starlightoptical .com
> telescope/optical stuff
>
> PS: Nice running into you over at Chabot
>