Re: TN 76 finished (for now)

[<aah@nofs.navy.mil>]

Michael,
  There are at several answers to your noise floor.
  First, with a 1mmag quantization, you have to add that
to the observed noise.
  Second, if you used ensemble methods for *all* stars
detected at least 5 times, you weight the zero point
towards the faint stars (obviously, there are more of
them).  Try with just a subset of stars around 9th mag.
  Third, at these levels, the accuracy depends on how
you form the digital aperture and sky annulus, and how
you subtract sky.  Sky is significant for all Mark IV
images.
Arne