G11 Periodic Error Analysis
    
The G11 is a great mount for the money.  In general I have had good success with the ST4 autoguider but occasionally I would get apparent wild swings in the readings followed by a loss of the star.  I decided to determine what the error was in the tracking by using the CCDTRACK software from SBIG. 

I set up the software to track a star with the relays inactive.  After each exposure of 2 seconds the coordinate of the star was logged to a file.  This file was then loaded into excel and the following graphs made.
      

 

 
As can bee seen from the RA axis chart, there is a relatively smooth error with the mount showing about 18 arcsec peak to peak error over a period of 4 minutes.
The dec axis is more puzzling.  In particular there are two large spikes which do not seem to make sense.  In addition, when I was using CCDTRACK with the relays active, the ST4 lost the star and it was due to a large swing in the DEC value.
 
All images and contents are © Copyright 2000 by Tom Blahovici. All rights reserved. The images and contents may not be reproduced, published, copied or transmitted in any form without written permission of the author.
    
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