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IAUC 3817: 1983d; 1982d

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                                                  Circular No. 3817
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


COMET IRAS-ARAKI-ALCOCK (1983d)
     G. Richter, Sonneberg Observatory, reports that further
prediscovery images have been found by Huth, Kroll and himself near
the plate limit on two simultaneous exposures.  The position is:

        1983 UT           R.A.   (1950.0)   Decl.      m1

        Apr. 17.0535     19 07 47.5     +46 57 14      12

     W. Altenhoff, W. Batrla, W. Huchtmeier, J. Schmidt, P.
Stumpff and M. Walmsley, Max-Planck-Institut fur Radioastronomie,
telex: "Radio observations at 13 mm using the Effelsberg 100-m
telescope (halfpower bandwidth 40") have resulted in the detection
of a pointlike radio continuum source with a flux of 8 mJy on May
11.5 UT.   We have also made detections of the  NH3 (3,3)  and the
22.2-GHz H2O lines, with main-beam brightness temperatures of 0.16
and 0.12 K, on May 11.6 and 12.6, respectively."

     R. Nolthenius, University of California at Los Angeles,
writes that he observed an occultation of SAO 98040 by the nuclear
region of comet 1983d on May 12.188 +/- 0.003 UT.  Visual
observations (at Lockwood Valley, CA, Long. 119deg01'47" west, lat.
34deg47'51" north, altitude 1630 m; 0.20-m Schmidt-Cassegrain, 275
x; seeing steady at 1"-1".5) showed the condensation to be not
quite resolved, distinctly fuzzy, ~ 1.3 mag fainter than the star.
The event lasted 0.8 s (corresponding to 31 km at the comet's
distance), during which the combined image slowly faded by 0.5
mag, then brightened, with no obvious interval of constant light.

     With further reference to IAUC 3801 and 3811, J. D. Drummond,
Steward Observatory, writes that his visual observations indicated
a definite minor meteor shower associated with the comet.  He
gives zenithal hourly rates as follows: May 9.47 UT, 5.1; 10.32,
4.1; 10.40, 3.2; 10.44, 3.1; 11.36, 2.4; 11.41, 3.2; 11.44, 3.1.

     Total visual magnitude estimates by V. F. de Assis Neto, Sao
Francisco de Oliveira, Brazil: May 11.92 UT, 2.6 (naked eye);
12.94, 3.8; 13.98, 5.2; 15.98, 5.4; 17.02, 5.4 (0.10-m reflector);
18.94, 7.5 (0.10-m reflector; 7'2 coma with 10 x 70 binoculars).


PERIODIC COMET TEMPEL 2 (1982d)
     Total visual magnitude estimates by J. Bortle, Stormville, NY
(0.32-m reflector): May 14.34 UT, 10.4; 18.34, 10.3.


1983 June 1                    (3817)              Brian G. Marsden

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