Quote: I'm not sure what's happening, but my results are elongated stars.Thanks!
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Quote:It would be helpful to know the direction of elongation. If the bottom of the camera is square to the dovetail plate, then RA is up and down and dec is left-right. If the camera is "sideways" (bottom of camera perpendicular to dovetail plate) then left-right is RA (East-West) and up/down is dec (North/South). If the camera is at some other orientation then neither axis is square to the frame and it's hard to tell unless you nudge the mount in one axis or the other during an exposure to see which way things move.
Quote:What are you guiding with to remove the mount PE?
Quote:The bottom of the camera is square to the dovetail plate. The direction of the elongation in the images is dec (left to right), then either a right-angle squiggle (left, 90 degree angle, up) or an RA (up), then another dec elongation (left to right).
Quote:You never said where you slewed to after your polar alignment....Polar alignment is different for different parts of the sky.. diffraction can becomes a major issue below 45degrees.. Seeing is another factor. I can get .5 arcmin polar alignment using various methods.. as the star tracks across the sky from the meridian to the horizon, the polar alignment error increases. Maybe this is your issue?This is one reason many use pointing models..
Quote:OK; two different things are going on. The dec drift pretty much only comes from polar misalignment so you may need to watch it more closely during drift alignment. Maybe watch it with the camera? The RA squiggle is mostly periodic error. A good PEC training should reduce that (at least, I THINK the Sirius has PEC).Careful alignment of the frames should keep it from growing when you stack.