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THE ASTRONOMER Electronic Circular No 863      1994 July 22 19.45UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP,England. Telephone/FAX(0256)471074 Int:+44256471074
INTERNET: GMH at AST.STAR.RL.AC.UK  or    GMH at GXVG.AST.CAM.AC.UK
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PERIODIC COMET SHOEMAKER-LEVY 9 (1993e)/COLLISION WITH JUPITER
Transits of Impact Sites
Jonathan Shanklin, Cambridge, UK reports the following transit
times (1994 July UT)for impact sites:
G       18.840; H       18.917; A       19.846; C       19.904;
K       20.790; L       20.857; G       20.903
Sites G, H, K and L very dark.  Sites A and C much lighter.
There was no sign of any impact flash from Q1 or Q2.The area had
rotated into view before seeing deteriorated, but the site was
similar in intensity to A and C.
Fragment L
Mark Kidger, Teide Observatory report the detection by Clara
Regulo, Jose Miguel Rodriguez-Espinosa, Peter Hammersley,
Jesus J. Fuensalida (Instituto de Astrofisica de Canarias) in the
1.5m Carlos Sanchez Telescope (at 2.167 microns) and by Mark Kidger
and Miquel Serra (Instituto de Astrofisica de Canarias) and Olga
Munoz (Instituto de astrofisica de Andalucia)  in the 82cm IAC-80
Telescope, both in Teide Observatory, Tenerife of the impact of
Fragment L with Jupiter. The event was detected on July 19 at
22:18UT in the IR and at 22:22 in the visible. The infrared
detection was the brightest so far with the Carlos Sanchez
Telescope, saturating the detector for several minutes. Maximum
was reached at 22:23. The plume was brighter than the whole disc
of the planet until 22:43 when it started to fade. During the
rise to maximum of the flare, the plume was seen to be clearly
double; this effect had reappeared by 23:00. In 892nm the plume
extended more than 5000Km above the edge of the disc and, although
less bright than Fragment H, extended further beyond the limb.
The visible plume had faded from view by 22:42, but then
reappeared at 22:49. At 23:02 the visible plume was considerably
brighter than in its initial maximum.
Fragment M
Among the wealth of messages received via the SL9 message centre,
one from J. Klavetter indicates that the impact of the missing
fragment M = 10 was observed at the San Pedro Martir station of
the Mexican National Astronomical Observatory. Observations mainly
at 2.1 microns showed a dim spot just beyond site C on
July 20.259 UT, and it continued to brighten until 20.299.
IAUC 6030
Fragment N
D. Crisp reports for the IRIS observers on the 3.9-m
Anglo-Australian Telescope that the impact flash from fragment
N = 9 was detected, using rapid-sampling imaging photometry with
a 2.34-micron filter rather than K-grism drift scanning, on July
20.441 UT.  The intensity of this flash increased slowly until
about 20.442, but it never exceeded 70 percent of the mean
surface brightness of the south polar hood.  On resuming the
observations on 20.446 after a problem with the instrument there
was no evidence of the N impact site.  K-grism drift scanning
from July 20.451 to 20.458 also showed no evidence of the N
impact site.
P. McGregor and M. Allen, Australian National Observatory,
report that CASPIR 2.34-micron observations showed the N impact
as a faint flash beginning on July 20.441 and lasting until
20.443, but subsequent narrow-band imaging failed to detect
the site.
IAUC 6030

Guy M Hurst







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Date: Sun, 24 Jul 1994 10:55:06 +0100 (BST)