RE: [APML] Focusing and temperature change issues during an exposure- advice wanted

["Greg Hartke" <ghartke@earthlink.net>]

That's an easy one, Alan, so you've probably already gotten responses.
However on the off chance that you haven't I can kick in some info.

The Optec TCF (which means something like "temperature compensated focuser")
is reputedly an excellent device. Dick Greiner was involved in some
prototype testing of this device. I posted him privately on the subject some
time ago and he said it worked excellently. Check it out at Optec's web
site. Keep in mind it isn't cheap but it does the job.

Greg

> -----Original Message-----
> From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On
> Behalf Of Alan Voetsch
> Sent: Wednesday, November 13, 2002 4:45 PM
> To: APML; MAPUG
> Subject: [APML] Focusing and temperature change issues during an
> exposure- advice wanted
>
>
> Hi all,
>
> I'm posting this to both APML and the MAPUG lists,
> sorry to those who'll get it twice.
>
> I want to find the most effective way to deal with the
> above issues during an exposure. Seeing as how most
> exposures now run in the 2-5 hour range, I think you
> can see how this would become a significant issue.
> Currently, all I have to go on is a change in
> brightness readings fron the autoguider. Those
> readings vary anyway, so it's probably not the best
> indicator, but right now it's all I've got.
>
> I've accepted the fact that a computer in the
> observatory is now a must along with a motorized
> focuser. So here's what I'm working with: 12" LX200
> (non-GPS), Taurus Tracker III, OM-1 guided with a
> 208XT.
>
> OK, so what's the best way to make sure that focus and
> temperature related issues are not screwing up a great
> shot?
>
> Thanks,
> Alan
>
>
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