[vsnet-chat 1891] V4444 Sgr

[aah@nofs.navy.mil]

Taking data last night on some fields near this novae
reminded me yet again that the center of the galaxy
is nearby.  Frames are basically white with stars
with short exposures.  CCD observers are cautioned that
they will have trouble removing the underlying faint
stars from their synthetic apertures, and therefore
magnitudes of the novae will be compromised.  As an
example, I've posted a 6arcmin field centered on
V4444 Sgr, taken through a V filter on the 1.0-m telescope
with a 30-second exposure time.  Even at this short of
an exposure, there is no 'bare' spot on the frames for
either sky determination or master psf stars.  Note
also that USNO-A2.0 fails rather dramatically here
due to the blackness of the photographic plate, and
that the Tycho stars have large errors.  Just a fair
warning as the variable gets fainter!  Find the
image at
  http://ftp.nofs.navy.mil/pub/outgoing/aah/temp/v4444sgr.gif
Arne

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