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Old 09-05-2011, 06:23 PM
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seeker372011 (Narayan)
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seeker372011 is offline
 
Join Date: Oct 2004
Location: Sydney
Posts: 3,652
A polar alignment mystery

I need figuring out what went awry

I did a really good polar alignment...I thought. The star stayed in the crosshairs for five minutes when I finished doing both alt and az adjustments
I didn't bother doing a second iteration because I was trying to image at 240mm,while auto guiding, so I thought close enough would be adequate

To my surprise I found huge star trails in my 25 minute first shot;I cut back to 5 minutes, and found I was still getting trails
Cloud came over before I could do any more
But how could this be?
One thing I did different though..I polar aligned using the guide scope, not the imaging scope that I would normally use
Surely this shouldn't matter?
The imaging scope and guide scope were not perfectly aligned..not even close..still surely that shouldn't matter?
The guide scope has a focal length of 900mmm and I was using star targ with a dsi as the camera

Any thoughts?
Would appreciate any comment, especially as it will probably be three months before I get another clear night to actually try it out again

Thanks in advance
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