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Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User
PeterAllday
member
Reged: 03/24/06
Posts: 22
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I have an image drift problem, if anyone can help that would be great. I am also autoguiding, and the stars in the bottom corner are nice and round, whereas the ones in the top left have trails.
Example here
http://picasaweb.google.co.uk/lh/photo/Z27R3OfEjuEtr6tiysLogw?feat=directlink
I believe that the mount is pretty level, and as well polar aligned as I can get it.
Does anyone have any thoughts as to what is causing it?
Thanks
Peter 
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Jerry Lodriguss
Vendor
Reged: 07/19/08
Posts: 576
Loc: Voorhees, NJ
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Hi Peter,
This is almost certainly from field rotation because the mount was not polar aligned accurately enough.
What mount is it? Have you tried taking the time to drift align it and then checking that against the polar alignment scope?
Jerry
--------------------
A Beginner's Guide to DSLR Astrophotography
http://www.astropix.com
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PeterAllday
member
Reged: 03/24/06
Posts: 22
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It is an EQ6 mount. I have tried drift aligning it once, but with not a great deal of success. I guess that it is time I tried again.
Peter
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Jerry Lodriguss
Vendor
Reged: 07/19/08
Posts: 576
Loc: Voorhees, NJ
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Hi Peter,
You should take the time to accurately polar align the mount with the drift method at least one time, to check the accuracy of the Polar Alignment scope.
You should also make sure that the reticle is correctly centered in the polar alignment scope.
I have a page on drift alignment here:
http://www.astropix.com/HTML/I_ASTROP/TRACKED/POLAR.HTM
It will initially seem much more complicated than it really is in practice. It is a little bit time consuming. But it is something you can do in your driveway on a night when the moon is up.
Jerry
--------------------
A Beginner's Guide to DSLR Astrophotography
http://www.astropix.com
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PeterAllday
member
Reged: 03/24/06
Posts: 22
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Thanks Jerry,
I will give this a go tonight assuming that it stays clear.
Peter
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dgpilot
super member
Reged: 09/25/09
Posts: 105
Loc: San Ramon, California
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Also, I've heard that having the guidescope pointed too far away from the imaging scope's target, it can produce the same results.
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LXD75 8" SN f/4
Canon 50D, 350D (unmodded)
Orion ST80 Guidescope
Meade DSI II Pro
San Ramon, California 
My Astro Gallery
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PeterAllday
member
Reged: 03/24/06
Posts: 22
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Well, it wasn't clear, so I haven't tied the drift alignment. I think that the guidescope is fairly well aligned, at least from looking at it, I haven't tested it.
The other change that I made recently was trying to get rid of cone error, which was noticable when going from one half of the sky to the other. This is now greatly improved, but this new problem has only arisen since then.
Peter
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