Another case use for the suggested "Center Object after XX exposures" will be to cope with bad behaved mounts. I'm using an old EQ5 with OnStep GOTO system attached. Sometimes, the mount "jumps" in Dec 2" or 3" without a reason (I'm begin to believe that is poor stability on the tripod/mount head combo). Between those jumps the tracking and guiding is reasonable for my image scale, but If I let the telescope unattended I usually end with a collection of perfectly tracked frames that will be drifting in Dec during the session. If you add that I'm using a small chip camera.... some sessions are completely unusable because I end keeping 60% or 50% of the field of view.

With this "Center Object after xx exposures", my chances to use all the frames will increase a lot

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