-------------------------------------------------------------------
THE ASTRONOMER Electronic Circular No 864      1994 July 24 09.35UT
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
-------------------------------------------------------------------
PERIODIC COMET SHOEMAKER-LEVY 9 (1993e)/COLLISION WITH JUPITER
Fragment P
Negative reports of K-band observations near the expected time of
the P = 8 impact were received from the South African Astronomical
Observatory (two groups), the Teide Observatory and Pic du Midi.
Fragments Q1 and Q2
The Pic du Midi team reported a very short, tiny flash in the K
band on July 20.822 that may have been due to fragment Q2 = 7b,
followed by a double flash from Q1 = 7a on 20.842 and 20.847, the
latter being the more prominent.  Plume phenomena were observed at
the Calar Alto Observatory around the impact times of the Q2 and
Q1 fragments; two spot-like features appeared over the impact limb
of Jupiter around July 20.822 and 20.847, the latter considerably
brighter than the former, and they were simultaneously identified
by direct imaging at 2.3 and 1.7 microns and by fast photometry
in the 3.1-micron range.  A further spot appeared over the limb
around July 20.842, and at 2.3 microns it was intermediate in
brightness between the others.  At the Teide Observatory the Q2
plume was noted on July 20.828 (evidently with the IAC-80
telescope at 750, 892 and 948 nm); the impact of Q1 was difficult
to separate from the Q2 plume, but it was clearly observed at
892 nm by July 20.851, the impact cloud later being clearly
double.  The Q2 impact did not show in the raw 2.166-micron data
from the Carlos Sanchez telescope, but the Q1 flare appeared on
July 20.847.
IAUC 6032
Fragment R
The impact of fragment R = 6 was detected at 2.34 microns using
CASPIR on the Australian National University 2.3-m telescope at
Siding Spring; distinct brightening began on July 21.237 UT and
continued until the detector saturated on 21.238; bright
emission at the impact site was detected at 4.78 microns on
21.242 but had faded by 21.256.  P. Nicholson and others using
the 5-m reflector at Palomar first noted the R flare at 3.6 and
5 microns on July 21.233; rapid brightening occurred on 21.237,
reaching a peak on 21.240, when diffraction spikes were observed
at 5 microns.  The 5-micron flux dimmed by a factor of 40 by
21.243, and the image was observed to be extended about 2" along
the limb on 21.246; by 21.249 the 5-micron flux had dropped to
the level of the first images, and by 21.258 it was comparable
to that of the planet.
IAUC 6032
Fragment S
The South African Astronomical Observatory reports via the SL9
message center that J. Shykula used the 1.9-m telescope for
high-speed K-band photometry of the impact of fragment S = 5.
Definite brightening began around July 21.640 UT, with peak
brightness around 21.645 and a return to relatively constant
signal levels by 21.651; peak brightness was nearly twice that
seen for impact Q, with a peak K mag about 1.19.  Using the 0.75-m
telescope and PtSi camera K. Sekiguchi obtained images of
Jupiter at 30-s intervals during the impact.  A low-level
brightening began around July 21.636 and began to fade before
a much more dramatic brightening began around 21.640.  Peak
brightness occurred around 21.645, and by 21.653 there was
definitely no remaining obvious excess brightness from this
impact.  The bright spot at the impact site could not easily
be separated from those for impacts R, G and D.  The S impact
plume was considerably brighter than that seen for fragment H.
Guy M Hurst







--- 00028 ---
Date: Sun, 24 Jul 94 20:44:15 +0100