Re: Focus indication

[<aah@nofs.navy.mil>]

Andrew,
  Are you sure the ellipse rotates?  I can see that the major axis
of the ellipse changes size, but the orientation of the axes should
remain fixed, and go from elliptical to circular to elliptical as
you move through the proper tracking rate.
  The problem Tom has is determining on which side
of 'correct' his current exposure resides.  Just as for focus
exposures, where you offset in Dec, change focus, offset in Dec, etc.
on the same frame, you can do something similar in RA.  Expose, go fast
forward, set new VCO voltage, expose, etc.  Then just look for the
image that has the smallest y (RA) fwhm.
Arne