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IAUC 4440: 1987u; 1987A

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                                                  Circular No. 4440
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM    Telephone 617-495-7244/7440/7444

     A new comet has been discovered by Michael Rudenko, Amherst,
Massachusetts.  The following observations are available:

       1987 UT         R.A. (1950) Decl.     m1     Observer
       Aug. 21.111    14 08.0    +34 00      9.5:   Rudenko
            21.20     14 08.1    +33 59             Morris
            21.24     14 08.0    +33 59      9.9      "

M. Rudenko (Amherst, MA).  0.15-m refractor.  Object diffuse with
   slight condensation, coma diameter 2'-3'.
C. S. Morris (Whitaker Peak, CA).  0.26-m reflector.  No
   condensation or tail.  Motion definitely detected.

     M. Karovska, P. Nisensen, C. Papaliolios and C. Standley, Center
for Astrophysics, report: "Follow-up observations were carried
out during May 30-June 2 with the purpose of detecting the second
bright source (IAUC 4382) using our speckle system and the CTIO 4-m
telescope.  Data were recorded in 10-nm bandpasses at H alpha and seven
other optical wavelengths in the range 400-775 nm.  Conditions were
fairly good (2"-3" seeing) on two of the four nights.  Careful
analysis of these data has not provided a certain detection of the
second source above the background noise.  For a certain detection
the magnitude difference at the time of these observations would
have to be less than about 4.  SN 1987A had brightened from mv about 4.1
at the time of our original observation (Mar. 23) to mv about 3.1 for
these observations, so if the second source remained at its originally
detected brightness the magnitude difference between it and
the supernova would have been about 3.7.  Data from additional
observations carried out in early July using the same telescope and
equipment are still being reduced.  The positions of the second
source relative to the supernova were remeasured in the reconstructions
from data taken on Mar. 23 and Apr. 2.  To the limits of accuracy
of the process (0".015) there was no detectable change in
the separation.  Better accuracy in centroid determination might
have been possible if the supernova were at a greater zenith angle,
where atmospheric dispersion would have less of an effect."

1987 August 21                 (4440)              Brian G. Marsden

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