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IAUC 4196: 1982i

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                                                  Circular No. 4196
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

     M. Feast, South African Astronomical Observatory, telexes the
following infrared magnitudes of P/Halley obtained by B. Carter
with the 0.75-m reflector at Sutherland (36"-aperture diaphragm,
170" chop):  Mar. 15.1 UT, J = 4.95, H = 4.54, K = 4.30, L = 2.08;
17.1, 5.50, 5.08, 4.87, 2.79; 18.1, 5.46, 5.04, 4.83, 2.85.

     A. Tokunaga, W. Golisch, and L. Bergknut, University of
Hawaii, communicate infrared observations made of P/Halley with the
NASA Infrared Telescope Facility (magnitudes obtained with 7"3
aperture; errors < 0.05 mag):  Mar. 6.9 UT, K = 6.3, L = 3.6, M =
1.3, N = -2.5, Q = -3.9; Mar. 12.8, 6.4, 4.2, 2.1, -2.0, -3.6; Mar.
13.7, 7.0, 4.7, 2.3, -1.8, --.  The color temperature of the dust
emission was 370 K on Mar. 6 and 345 K on Mar. 12; the silicate
emission at 9.8 microns was ~ 0.6 mag above the continuum.

     R. M. West reports the following information from photographs
taken (mostly with the 0.4-m astrograph) at the European Southern
Observatory, La Silla:  On Mar. 1.4, the nucleus was 2" or less in
size and round; exposures of 20 and 60 s show a segment emanating
from the nucleus at p.a. 0 and curving toward p.a. 270.  On Mar.
2.4, the nucleus appeared much brighter, 2" across, and at the west
edge of a bright segment, indicating an outburst had occurred in
the preceding 24 hr.  On Mar. 3.4, the nucleus was again somewhat
fainter than the preceding day; the total intensity of the first
degree of tail length outward from the nucleus had decreased somewhat
over the previous 3 days, especially in red.  On Mar. 4.4, a
very noticeable decrease in 24 hr in the red brightness of the nucleus
(~ 0.5 mag or more) and of the surrounding matter was visible;
however, there were more streamers in the tail within 1 deg of the
nucleus on blue exposures.  On Mar. 5.4 and 6.4, the nucleus was
somewhat brighter than on Mar. 4.4.  On Mar. 7.3, a major outburst was
recorded, with the nucleus being about 1 mag brighter than on Mar.
6.3 and elongated on even the shortest exposures.  P. Bouchet, F.
Dossin, and P. Monderen report observation of a clear secondary
condensation, anti-solar from the main condensation, on Mar. 19.3
with the La Silla 2.2-m and 1.5-m reflectors and 0.4-m astrograph.

     Further total visual magnitude estimates (cf. IAUC 4194): Mar.
13.10 UT, 3.0 (J. Campos, Durban, South Africa, naked eye; tail 5 deg
long in p.a. ~ 275 ); 17.52, 2.8 (C. S. Morris, Little Rock, CA,
naked eye); 20.52, 2.8 (Morris, tail length ~ 10 deg).

1986 March 20                  (4196)            Daniel W. E. Green

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