Re: [APML] OT: AP Oil Spaced Lenses

["Jim Janusz" <jjanusz@ix.netcom.com>]

Hey John,

You just gave me some info. I was unaware of.  I thought the 7-7 was oil
spaced.  Now I understand what the slight stains are at the very outer edge
of the cell.

Gel, well I'll be damned!  Did Roland say what the gel is made of?  Is it
petroleum based?

Jim
----- Original Message -----
From: John Gleason <dvj@earthlink.net>
To: <astro-photo@seds.org>; <astro-photo@seds.org>
Sent: Wednesday, June 21, 2000 4:27 PM
Subject: RE: [APML] OT: AP Oil Spaced Lenses


> Chuck,
>
> My 7" f/7 is gel spaced not oil spaced. The gel used is from the fiber
> optics industry.  I can see changes in the gel when there is thermal shock
> to the cell during cool down.  The cell is sealed, but there does not
> appear to be a manifold to compensate for contraction or expansion of the
> lens elements.  Roland told me so.  The 6" f/7.1 that I also own (7 years
> old) is oil spaced as per Roland.  This appears in early 90's AP
> literature.
>
> jg
>
>
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