Central Bureau for Astronomical Telegrams
IAUC 3572: 1980 S 6; (1537); TIME ADJUSTMENT ON 1981 JUNE 30
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Read IAUC 3573
Circular No. 3572
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
1980 S 6
H. J. Reitsema, Lunar and Planetary Laboratory, writes that an
orbit for 1980 S 6 = 1980 S 10 = ..., popularly known as 'Dione B',
has been determined from 76 ground-based observations reported on
these Circulars or measured at L.P.L. and also from several Voyager
1 observations. The best fit to the data gives a period of libration
about the L4 point in the Saturn-Dione system of 787 +/- 1 days,
with orbital-longitude extremes of 76o.4 and 46o.9 +/- 0o.2 relative to
Dione (Saturn IV). Maximum separation occurred on 1980 Apr. 20.7
UT. Further predicted separations are: 1980 Dec. 27.0, 57o.0; 1981
Feb. 15.0, 51o.7; Apr. 6.0, 48o.0; May 26.0, 46o.9; July 15.0, 48o.7.
(1537) TRANSYLVANIA
L. K. Kristensen, University of Aarhus, suggests that, of the
several post-discovery-opposition observations attributed to this
object, the original provisional designation of which was 1940 QA,
the only ones that might be correct are the pair obtained at the
Goethe Link Observatory on 1962 Dec. 30. As with (1538) Detre (cf.
IAUC 3558, MPC 5788), the orbit determination for this object is
rendered difficult by the unavailability of reliable observations
from the discovery opposition. If the 1962 identification is correct,
the following ephemeris, which differs by 1o-2o from that in
Efemeridy Malykh Planet for 1981, should be correct to 1'-2'.
Positive or meaningful negative observations would be useful.
1981 ET R. A. (1950) Decl. Delta r Mag.
Feb. 15 14 16.51 -15 42.1
25 14 16.71 -15 43.5 3.387 3.959 18.8
Mar. 7 14 15.15 -15 35.6
17 14 11.84 -15 17.9 3.137 3.951 18.6
27 14 06.95 -14 50.9
Apr. 6 14 00.79 -14 15.4 2.975 3.941 18.3
16 13 53.81 -13 33.5
26 13 46.56 -12 47.9 2.927 3.929 18.0
TIME ADJUSTMENT ON 1981 JUNE 30
The Bureau International de l'Heure informs us that a positive
leap second will occur such that the of UTC second markers
will be: 1981 June 30d23h59m59s, 30d23h59m60s, July 1d00h00m00s.
1981 February 12 (3572) Brian G. Marsden
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