Re: Switching Scopes on 900GTO

Joe Zeglinski

Hi Hunter,

On the question of aligning all your scopes, would it not be possible to
determine the "pointing error", for each scope, without it being precisely
aligned, and simply plug in the correction to the target coordinates, based on
that predetermined fixed offset? It would be nice if something like that could
be done right in a Planetarium program, so as you switch and specify which OTA
you are using, the program compensates for you.


----- Original Message -----
From: "hewholooks" <hewholooks@...>
To: <ap-gto@...>
Sent: Friday, January 18, 2008 3:23 PM
Subject: [ap-gto] Switching Scopes on 900GTO

Sorry, but another almost owner question.

I currenly image with 3 different scopes - Orion ED80, APM/TMB
130/780, and C9.25. I place these on my mount one at a time on a
dual saddle and guide with an ST80 on the other side of the saddle.

Most likely these scopes point in slightly different directions when
mounted in the saddle and probably none are exactly orthogonal. I
would plan on doing the same with the 900GTO, although I will leave
the mount set up in an observatory, not changing the polar allignment
from night to night.

As I understand it, the AP mounts are dependent on orthogonality to
perform accurate gotos across wide sections of the sky, so that will
leave me out (unless I spend the time making each scope orthogonal on
it's respective dovetail). If that's true, I can live with it
because I hardly ever observe and most always image, syncing on a
star nearby to my intended object and slew a few degrees from there
to the object.

Question is - assuming I am not totally skewed in my orthogonality,
will this work out for me? - that is - syncing close to my subject
and expecting the mount to get me close enough to be within a FOV of
the target.

Second question is - after I image one target and want to go to
another that night, should I sync on a star near the new object and
proceed in the same fashion that I did with the first object, or do I
need to turn off the mount and start over so as not to corrupt my
planetarium alignment with another sync?

Third - when the session is over, should I turn off the mount as if I
were taking down a temporary setup for the night in anticipation of
using another OTA the next session, or should I park the mount first?

Thanks in advance.


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