RE: [APML] New Images Posted

["Jon Kolb" <jkolb@datawest.net>]

Chuck,

> Nice wide field shots.

Thanks - that's really satisfying coming from someone of your expertise
and experience.
 
> At +70 Dec, it is very sensitive to polar alignment so field rotation 
> can
> be a problem. If you've had varying results due to guiding 
> I'd look at that.

This was the only shot of the night that had any trouble, and was the
highest Dec target as well, so I think you're probably right about the
cause.  The STV was putting out corrections as large as 1.8 on both
axes, which sounds a lot like field rotation since it was on both axes.
If it were only or mostly in one direction, I'd suspect balance problems
instead, and they'd be a factor on every shot.  Normally, I get around
0.4-0.7 averages with the STV/MI-250.

Sincerely,
Jon Kolb
Adventures in Astrophotography
http://home.datawest.net/jkolb/
jkolb@datawest.net






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