THE ASTRONOMER Electronic Circular No 481 1991 Jan 29 20.45UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke,
Hants, RG22 4PP, England. Telephone: (0256)471074 Int:+44256471074
Telex: 9312111261 Answerback: TA G Microlink: MAG60138
JANET:GMH @ UK.AC.CAM.ASTRONOMY.STARLINK GUYH@UK.AC.SUSSEX.CLUSTER
TELECOM GOLD: 10074:MIK2885 PRESTEL 256471074
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TELECOM GOLD
With the impending closure of MICROLINK, the Editor has
re-established a telex number on GOLD for urgent incoming messages.
This new personalised number is:
9312111261 Answerback (TA G)
Successful tests have been carried out with CBAT.
GOLD have also announced that all mailbox users must change to the
personal telex option as the earlier 'master GOLD number' with
reference lines is to be withdrawn following improvements to the
system.
If anyone requires application forms to join TELECOM GOLD these are
now available by e-mail request from the Editor.
URA SHUTTLE EXPERIMENT
Diane Dupre of Los Alamos Laboratory has e-mailed details of this
project and advises that the latest estimate for launch of
'Discovery' is Feb 28. If anyone requires the full message (very
long!) please e-mail the Editor.
COMET ARAI (1991b)
Prediscovery images of this comet (m1 about 10) were found on films
exposed 1990 Dec. 23 by T. Ohtsuka and T. Kojima, Tatebayashi,
Gunma, Japan. The following improved parabolic orbital elements by
S. Nakano, Sumoto, Japan, are from MPC 17596:
T = 1990 Dec. 11.070 ET Peri. = 337.762
Node = 114.841 1950.0
q = 1.43596 AU Incl. = 71.119
1991 ET R.A. (1950) Decl. Delta r m1
Jan 29 7 33.73 +54 59.2
Feb. 3 7 12.65 +59 35.7 0.787 1.627 11.6
8 6 52.84 +62 53.0
13 6 35.48 +65 12.1 0.975 1.697 12.2
18 6 21.39 +66 50.2
23 6 10.91 +68 00.4 1.176 1.773 12.8
28 6 04.03 +68 51.9
Mar. 5 6 00.50 +69 30.7 1.383 1.856 13.4
IAUC 5170
1991 BA
An asteroidal object of V = 17.5 was discovered in Cancer on
Jan. 18.23 UT by D. Rabinowitz with Spacewatch, Kitt Peak, and
followed by him and J. V. Scotti for 5 hr, during which time it moved
7.1 deg to the east and south. From seven measurements by Scotti,
B. G. Marsden established that this was an Apollo object with the
following approximate orbital elements: T = 1991 Mar. 2.06 ET, Peri.
= 70.58, Node = 118.34, i = 1.96 (equinox 1950.0), q = 0.713 AU, e =
0.682, a = 2.24 AU. All the observations are satisfied within 1",
so there is no possibility that this was an artificial object in a
geocentric orbit. With H = 28.5, the object was presumably some ten
times smaller than 1990 UN (cf. IAUC 5130), until now the celestial
object of smallest known size, and 1991 BA is thus estimated to be
only 5-10 m across. During the observed arc, the topocentric
distance of 1991 BA decreased from 0.0052 to 0.0033 AU, the latter
distance being closer than any natural object outside the atmosphere
has been known to come. It passed the earth at a record (geocentric)
miss distance of 0.0011 AU (170 000 km) on Jan. 18.72 UT and moved
into the daytime sky.
IAUC 5172
Guy M Hurst