[AZ-Observing] Plotting Periodic Error

  • From: pulind@xxxxx
  • To: az-observing@xxxxxxxxxxxxx
  • 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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