[vsnet-chat 2126] sn1999cp field photometry

[aah@nofs.navy.mil]

Berto asked if I could get some photometry to resolve
the zero point differences in this field.  The weather
during my observing run has been poor to abysmal.
However, I did observe this field through cirrus, and
there is a Tycho star near the galaxy.  The transformed
values for that star are:

  Tycho 4981-353-01  V 8.35  B-V  +0.80  errors ~0.02mag
  
If you use this star as a zero point, then the magnitudes
and colors as given in
  http://ftp.nofs.navy.mil/pub/outgoing/aah/sequence/sn1999cp.dat
should be corrected by
  V = Vdat - 0.04
  B-V = (B-V)dat + 0.47
This will at least give a consistent magnitude scale.
I have two more nights in my run, with less than 50-50
chance of any clear hours.  If it does clear off, I'll
update this file with real calibrated photometry.
Arne

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