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IAUC 3257: V1500 Cyg; 1978f; Notice

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                                                  Circular No. 3257
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM     Telephone 617-864-5758


V1500 CYGNI
     J. C. Kemp, R. King and P. E. Johnson, Physics Department,
University of Oregon, write: "Photometry in unfiltered light (S-20
response) on the 81-cm telescope at Pine Mountain on seven nights
during Aug. 11-20 showed a lightcurve with predominant period 3.358
hours and peak-to-peak amplitude 0.32 magnitude.  Some suggestion
of a double period (6.7 hours) has appeared again: see Kemp, Sykes
and Rudy (1977, Astrophys. J. 211, L71).  Our current ephemeris in
terms of the possible double period is 1978 Aug. 1.55661 + 0.21984
E.  This epoch seems to correspond to the deeper of the two minima;
and the first maximum, in this phasing, is the higher of the two.
The maxima are decidedly peaked; in general, the curve appears
ellipsoidal in character, rather than of an eclipsing type.  Since
the double period may well be a spurious statistical effect,
comparison with current lightcurves by other observers is urgently
sought.  The mean magnitude in unfiltered light was estimated as
13.4, roughly a V magnitude; but the nebular lines, which presumably
do not manifest the 3-hour variation, should be subtracted.
Thus the nuclear object is fainter, and the true variation amplitude
is deeper than noted above."

     Recent visual magnitude estimates at the Harvard Observatory:
July 1.18 UT, 14.3 (D. W. E. Green); 13.23, 14.2 (S. O'Meara).


COMET MEIER (1978f)
     Further total visual magnitude estimates: July 12.10 UT, 7.9
(J. Bortle, Brooks Observatory, 32-cm reflector); 14.11, 8.3 (P.
Maley, Houston, Texas, 15-cm refractor).


NOTICE TO CONTRIBUTORS
     Repeating the notice on IAUC 3231, we request that material
for these Circulars (and for the Minor Planet Circulars) generally
be communicated to us, either by TWX/telex/telegram/cablegram to
the TWX number given above, or by letter (sent by airmail from
points outside North America).  The telephone number given above
is available for receiving brief (up to 30 seconds duration)
recorded messages.  Telephone calls to the regular office number or
to the private home number of the undersigned should be made only
in cases of extreme urgency.


1978 August 25                 (3257)              Brian G. Marsden

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