[AZ-Observing] Re: Plotting Periodic Error
- From: "Wayne (aka Mr. Galaxy)" <mrgalaxy@xxxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Tue, 7 Feb 2012 06:00:19 GMT
15480 Empire Rd.
Benson, AZ 85602
hm ph: 520-586-2244 Wow, Paul, a Shaefer mount!! That's usually only owned by a
southern Californian or maybe someone who's been to the RTMC in the good old
days (the late 70's anyway). Nearly everyone who was anyone in astrophotography
(not me...) in the Orange County Astronomers (OCA) owned one of Bill's
telescopes along with a Tom Cave or Enterprise Optics mirror. I'm curious about
the tracking jump. Is there some dirt (or other imperfection) on the worm gear?
Clear skies,
Wayne (aka Mr. Galaxy)
---------- Original Message ----------
From: pulind@xxxxx
To: az-observing@xxxxxxxxxxxxx
Subject: [AZ-Observing] Plotting Periodic Error
Date: Sun, 5 Feb 2012 22:04:04 -0500 (EST)
Last night I used my guide-scope and Orion guider (with PhD software) to plot
periodic error. The main scope was idle. PhD was set to "Disable Guide
Output" and a guide star was selected near the equator. Then "unguided
guiding" was started. Below is a link to the output graph produced by PhD. It
shows the overall RA periodic error and an abrupt irregularity in the worm that
come around every rotation. Good polar alignment is necessary to use a guider
for this, and the image-scale of the guide-scope must be known.
Conclusion: The Byers gear on my Schaefer mount is OK but definitely not great.
Peak-to-peak PE is 16 arc-sec.
Here's the graph and a couple pix of the 12.5 inch astrograph. Just click on
the thumbnail to see the graph:
http://www.pbase.com/paullind/equipment
Paul Lind
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