Horizontal Heavens Observatory "...From  A Galaxy Far, Far Away"
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This page was last updated on 01/22/15.

Bad Winding in RA Motor - Imaging Issues

This took a long time to figure out the culprit because the symptomatic jumps at first to seem sporadic.  It wasn't until I put a stop watch to them and associated a "click" in the mount that I realized the RA motor was stopping in the dead spot and then "jumping" ahead when a stronger pulse allowed the motor to "jump" the bad spot in the winding.

Below are a portions of; first a 10min "unguided" ST-10XME image and, second a 20min guided image of IC1848 in the NNE quadrant of the sky.  Both were  taken at 384mm focal length on my MI-250.  Guiding on second image conducted at 660mm 2x2 binning with an ST-402ME. 

(below) 10min tracked only- NO GUIDING                                                                                 (below) 20min GUIDED