To: atm{at}shore.net
From: tkrajci{at}san.osd.mil
Reply-To: tkrajci{at}san.osd.mil


>From: "Mel Bartels" 
>
>That's why the RoboFocus and other temperature compensating devices are so
>popular despite their steep pricing.  Re-focusing for digital imaging is
>often necessary every few minutes because of temperature changes anyhow.
>
>If
>you change objects and move to another quadrant of the sky, swinging the
>scope from vertical to horizontal, you likely will go through a re-
>focusing
>session anyhow.

Mel,

What have you heard about athermal optical tube assemblies...do they
maintain focus tolerance as the scope is moved to new targets...or is the
concept of an athermal optical tube assembly more market hype than
practical use to the amateur with a finite budget?  (I'm sure you can make
an athermal OTA that has no appreciable focus shift as the OTA is pointed
to new objects...but does this level of engineering drive the price or
difficulty of contruction way up?)

Thanks in advance,
Tom Krajci
Tashkent, Uzbekistan

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