Psy1280 What can cause a target to drift away from center?
Was this a slow drift (each subframe progressively moving away), or is it a displacement (all subframes are off by about the same amount).
If it is a progressive drift, and assuming that your guide graph is good, then the top two suspects would be (1) inaccurate polar alignment causing field rotation, and (2) differential flexure between the guide scope and main OTA causing the mount to be guided away from your OTA's center.
If all subframes, including the first subframe, are displaced, you may have yourself moved the center of the frame after the image on the tablet had been magnified (two fingers to zoom). When you use two finger zooming, the center of the preview window is no longer the center of the frame. Unlike other programs, there is no way in ASIAIR to zoom with the center ROI locked.
If you want to properly center a zoomed target, first go the preview window, select Tools icon, and turn on the crosshairs. The center of the crosshair will show the true center of a full frame. Turn the crosshair off when you are finished centering, or you can keep it on the whole night to monitor for any drift.
Finally, when you are stacking, be sure to select a reference frame that has your target centered. Most stacking programs default to the first subframe as the reference frame, but they usually also allow you to select a different subframe as the reference.
Chen
