[vsnet-alert 1025] (fwd) Nova Sco 1997 (possible precursor image)

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

  I have received the following message from Howard Lanning on the possible
precursor image of Nova Sco 1997.

From LANNING@stsci.edu Tue Jul  1 02:06 JST 1997
Date: Mon, 30 Jun 1997 13:06:09 -0500 (EST)
From: Howard Lanning/STIS Contact Scientist <LANNING@stsci.edu>
Subject: Nova Sco 1997 (possible precursor image)

==================================================

  Following the recent postings of the Ouda images of Nova Sco 1997, the 
field was re-examined on the associated plate from the Sandage Two-color Survey
of the Galactic Plane.  This survey consists of plates with images taken in B 
and U on the same plate separated by 12 arcseconds.  Limiting magnitude
is typically around 20 in the B.  The plate was taken with the Palomar 48-in
Schmidt telescope 11 May 1969.

  Consistent with the report of G. J. Garradd (IAU Circ. 6678) an image
at B~18.5-19 and with a color of U-B~+1.0 is noted equidistant in the pattern 
of 3 stars described by A.C. Gilmore.  Garradd indicated this red star may be
USNO A1.0 (R = 18.7, B = 19.0). The Nova was of similar brightness to the 
two outlying stars (B~11.4).

  A second red star within 1 arcsecond of the USNO star (in the SW direction)
is also seen on the Sandage Two-color plates.  However, based upon the Ouda
images, Nova Sco 1997 appears offset to the west from the center position of
the 3 stars described above.  A hint of an image at the plate limit (B~20:) of 
the Sandage survey plate) was noted about 13 arcseconds to the West of the USNO
star and ~0.5 arcsecond North (immediately adjacent to what would be the UV
image of the two-color pair).  Although identifications can be highly 
questionable when working at the plate limit, the image does appear to be
consistent with the location of the nova.
  
                             Howard Lanning
                             Computer Sciences Corporation
                             Space Telescope Science Institute

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