ESO SL9 NEWS BULLETIN 
=====================

Issue	: 13
Date	: Friday, July 22, 1994, 08:00 UT (10:00 CEST; 04:00 Chilean time)
Items	: 13-A: Bad weather at observatories in Chile 
	  13-B: The last impacts
          13-C: Galileo, Ulysses and Voyager
	  13-D: International Ultraviolet Explorer (IUE)
          13-E: More spectral observations
          13-F: Large rings around impact zones ?
          13-G: Observations around the world
          13-H: Last issue of this bulletin

13-A. BAD WEATHER AT OBSERVATORIES IN CHILE

The astronomers at the ESO La Silla Observatory, as well as at the
Cerro Tololo Interamerican Observatory and the Las Campanas
Observatory, have been unable to observe the SL9 event for three
days because of bad weather. Initially the cloud cover was so
thick that not even the Moon could be seen, and last night clouds
descended on the observatories with high humidity and deposited ice on
the domes. The sky was entirely clear at altitudes just a few hundred
metres higher !

This has been a rather frustrating experience, but it now seems that
the bad period is over and observations may resume this
afternoon. While there will be no more impacts to observe, it will be
possible to follow the developments of the impact sites. Moreover, at
the ESO 3.6 metre telescope a long series of infrared Jupiter images
will be now be obtained which will hopefully make it possible to
detect the predicted vibrations of the entire planet and hence
investigate the inner structure. The TIMMI and IRSPEC observers expect
to catch up by also observing during the day which is possible with this
far-infrared instrument.

13-B. THE LAST IMPACTS

During the past five and a half days, the fragments of SL9 continued
to hit Jupiter. Every few hours or so, new reports were received about
sightings of flashes and rising fireballs, some stronger or fainter
than others, and often different in terms of altitude and duration.
Identifications became more and more difficult, as more and more
high-level infrared-bright features emerged over the many impact
sites.  Life will be strangely empty when there will be no more to report
after the final impact of W, predicted almost exactly when this
bulletin goes to press. Here is the latest news about the recent impacts.

First a great surprise: After the apparent detection of the impact of
the missing fragment M and the subsequent doubts (item 12-B),
observations with the Keck telescope at Hawaii settled the matter by
imaging the impact site of M. It was, after all, clearly separated
from that of K, which came into view a little later.

This telescope was also first to see the impact of fragment
R. The W.M. Keck Observatory comet impact team (Imke de Pater, James
Graham and Garrett Jernigan) reported that at UT 5:33 (July 21) they
detected the first flash from this event, followed within 45 sec by a
second flash; each flash lasted for 15 - 20 seconds: a truly
remarkable phenomenon. Approximately 8 minutes later the plume
appeared behind the limb; it brightened considerably and faded again
over a period of approximately 8 minutes.  Because of the weather
conditions (clouds, high cirrus), these observations were made in a
narrow K-band filter (2.3 micron; 1 percent CO filter). The frames
were obtained every 7.5 seconds, with an integration time of 4.2
seconds. After this, the dome had to be closed because of high
humidity.

In Australia, the AAT 3.9 m Observing Team, David Crisp (JPL), Vikki
Meadows (JPL), Stuart Lumsden (AAO) and Steve Lee (AAO) have been
using the InfraRed Imaging Spectrometer (IRIS) on the 3.9 m
Anglo-Australian Telescope (AAT) at the Siding Spring Observatory
(near Coonabarabran, Australia) to monitor the impacts.  On 21 July,
the observations were initiated at 04:28 UT.  The sun was still high
in the sky (2:28 PM local time), but the sky was clear, and the seeing
was initially about 1 arcsec. The detection of the fragment R impact
fireball was a special challenge because it occurred while the sun was
up, and because it was predicted to occur just as the the impact sites
of fragments D and G were approaching the morning limb.

A distinct, bright, point-like source first appeared on the morning
limb at 05:34 UT and was tentatively identified as the impact fireball
from fragment R.  At 05:42, as the seeing improved, this feature
brightened dramatically, until it was at least 200 times brighter than
the South Polar Hood at 2.34 microns.  By 05:50 UT, its brightness had
decreased by at least a factor of 25.  At approximately 06:00 UT, a
bright feature came over the limb, but it was not possible to
determine if this was the impact site of fragment R, or that of G, D,
or Q2.

Colleen McGhee, Phil Nicholson, Gerry Neugebauer, Keith Matthews, Tom
Hayward, Jeff Van Cleve, Alycia Weinberger, John Miles and Dave Shupe
successfully observed the R impact from the 200-inch Hale telescope at
Palomar, with simultaneous observations at 3.6 microns, 5 microns,
interleaved with 10-micron spectra at 10-minute intervals.  The first
indications were seen at 05:35 UT at 3.6 and 5 microns.  The rapid
brightening of the site was recorded at 05:41, reaching a peak at
05:46 UT.  The 5-micron flux dimmed by a factor of 40 by 05:50 UT.
The image was observed to be extended along the limb at 05:51 UT and
approximately 2 arcsec long at 05:54 UT.  After approx. 06:00 UT, the
10-um flux appeared to be constant.  By 06:12 UT, the 5 micron feature
had faded to a brightness comparable with the planet.  At 06:23 UT, it
was almost gone, at an airmass of 4.17.

The NASA/Infrared Telescope Facility reports observing a bright plume
associated with the impact of fragment R, at 05:40 UT, using the
MIRAC2 mid-infrared array camera.  The fireball was observed at
wavelengths of 7.85, 10.2, and 12.2 microns at intervals of 50 seconds
per cycle.  The emission increased at all three wavelengths for 5 - 10
minutes, then decayed on a slower time scale.  At its brightest, the
fireball's surface brightness was at least 50 times that of Jupiter at
all three wavelengths (The NASA/IRTF Comet Collision Science Team).

The McDonald Comet Impact Science Team was fighting clouds the entire
night.  Continuous integrations were made with the ROKCAM instrument
on the 2.7-metre telescope in the H2 filter at 2.12 microns, with the
CCD camera on the 0.8-metre telescope using a 893 nm filter, and with
a low resolution CCD spectrograph on the 2.1-metre telescope.  At
5:41:36 UT, a dramatic brightening was observed on the east limb with
ROKCAM.  The spot had brightened by a factor of 2 in the 18 seconds
between consecutive images.  About 20 minutes after the flash, the
clouds rolled in again.  In contrast, the 0.8m CCD images did not show
any obvious brightening at the same time, nor did the CCD spectra from
the 2.1m.  However, all of the spots from the previous impacts were
clearly visible to both CCD instruments.

A bright feature was detected on the limb of Jupiter beginning at
05:42 UT using an 8900 A methane filter with the Perkins 1.8-m
telescope at Lowell Observatory.  The on-set time is consistent with
detections by numerous IR observers of the fragment "R" fireball.  The
feature persisted until approximately 06:00 UT, by which time a large,
dark feature became visible in narrow-band filters at 4060 A and 6560
A and a bright feature in the methane filter - presumably impact site
G - rotating into view (David Schleicher (Lowell Obs.), Mark Wagner
(Ohio St. U.), Peter Birch (Perth Obs.), and Siobhan Sackey
(N. Arizona U.)).

SPIREX at the South Pole observed the fragment R impact at 05:44 UT.
The observers estimated that the impact site was as bright as event E,
at 2.36 microns.  Again, the South Pole has been experiencing
intermittent cloud, but the sky was clear around the time of impact.
Mark Hereld, Hien Nguyen, Bernard J. Rauscher and Scott A. Severson
(Astronomy & Astrophysics Center, University of Chicago) have started
to make some progress reducing the several thousand frames taken at
approximately hourly intervals in several narrow band filters over the
entire course of the impact sequence.  It is expected that there will
be almost uninterrupted coverage of the impact sequence and subsequent
evolution of the impact sites.

Clouds in central Baja, Mexico, allowed the observers at the San Pedro
Martir Observatory to do a more accurate reduction of the R impact
flash which was observed with the Camila IR Camera at 2.122 micron
(narrow H2 filter). They found that the rise time was incredibly fast
and distinctly different from the larger L impact flash seen the day
before.  The flux increased by a factor of 2 in less than 1 minute.
It stayed at maximum brightness for about 5.5 minutes at a nearly
constant level, and then was down to near its pre-brightness levels in
again less than 1 minute.  It was brighter than Io at maximum,
although not as bright as the L impact flash.

The Calar Alto Observing Team (Tom Herbst, Kurt Birkle, Ulrich Thiele,
Doug Hamilton, Hermann Boehnhardt Alex Fiedler, Karl-Heinz Mantel,
Jose Luis Ortiz, Giovanni Calamai, Andrea Richichi and Bringfried
Stecklum) reported that the impact plume of fragment S was detected at
15:29 UT (July 21) with the MAGIC camera on the 3.5-metre telescope in
the 2.3 micron range. It became brighter than the nearby spots of
previous impacts less than 2 minutes after detection. Starting from
15:33 UT it eventually reached the level of the other bright spots.

The Calar Alto Team continued to monitor the eastern limb of Jupiter,
but there was no sign of the T impact (which was predicted to occur at
18:04 UT before sunset at Calar Alto). However, the T impact site was
on top of the E and F spots which made identification of the event
difficult. The U fragment was predicted to strike in the old K
site. The observers saw a brief rise in the brightness of the region
at 22:10 UT lasting perhaps a minute. If this was the U impact, then
it certainly was unlike previous events!

At the South African Astronomical Observatory, Jeff Shykula of RPI
used the 1.9-metre telescope and infrared photometer for high-speed
K-band photometry of the impact of fragment S. Definite brightening
began at about 15:22 UT, with peak brightness at about 15:29 and a
return relatively constant signal levels by 15:37. Peak brightness was
nearly twice that seen for Q1, with a peak K magnitude of about 1.19.
Kaz Sekiguchi used the 0.75-metre telescope and PtSi camera to obtain
images of Jupiter at 30-second intervals during this impact. A
low-level brightening began at about 15:16 UT, and began to fade
before a much more dramatic brightening began at about 15:22. Peak
brightness occurred at 15:29 - 15:30 and by 15:40 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.  This impact plume was also considerably brighter
than that seen at the impact of fragment H.  K-band images and
high-speed photometry around the expected time of impact for fragment
T showed no obvious brightening before 19:00 UT. Detection of
low-level brightening was made difficult by bright spots at the limb.

Despite extensive monitoring at the Palomar 5-metre telescope,
infrared cameras at the 2.1 and 2.7-metre telescopes at the McDonald
Observatory (Texas), the NICMASS infrared camera at the Whately
Observatory (Massachusetts) and the Swedish Solar Telescope at La
Palma, no flash which could associated with the U impact could be
seen.  It therefore appears that the plumes from the impacts of
fragments T and U may not have been directly observed, but the impact
sites were definitely seen, when they rotated into sight.

Thus, the Arizona-Florida-Spain Team at the 4.2 m Willaim Herschel
Telescope, La Palma, reports observations of the T impact site starting
at approximately 20 UT (before sunset), showing spatial structure down
to the sub-arcsecond level different from that observed in other
impact sites. More specifically the arcs extended to the northeast
instead of to the southwest of the impact spot. The team also reported
that until approx. 23:30 UT with Jupiter at a high airmass no obvious
U impact spot was detected.

Daniel W.E. Green and Stephen J. O'Meara (Harvard College Observatory)
report: "At 23:20 UT (July 21) visual observations commenced in
daylight with the 23-cm Clark refractor at Harvard College
Observatory, Cambridge, Mass.  The large K impact site was immediately
visible at the morning limb, as were sites C just past the meridian
and A well over toward the evening limb.  Site C was quite obvious.
At about this time, Steve O'Meara also noticed that site K appeared to
be double (like a tight "snake bite") with surrounding diffuse
material to the south.  The second (darker, following) spot transited
the meridian at about 00:50 UT (July 22), suggesting strongly that
this may in fact be the fresh impact site of fragment U, which had
been predicted to transit about this time."

The U impact site was also seen at the Table Mountain Observatory
(1.2-metre telescope, Wrightwood, California). Here, Padma
A. Yanamandra-Fisher and the TMO Team started to observe Jupiter at
00:55 UT in a 8900 A filter with 1 sec integration times. They were able
to discern the impact site of fragment U as it transited the central
meridian. 

Soon after the predicted time of the V-impact (04:17 UT, 22 July),
negative reports started to come in. Despite careful monitoring, it
was neither seen at the Steward Observatory 90-inch telescope (Kitt
Peak, Arizona), nor at the AAT in Australia or at Palomar.

13-C. GALILEO, ULYSSES AND VOYAGER

The Photopolarimeter Radiometer on the Galileo spacecraft observed
Jupiter for 18 minutes during a period corresponding to earthbased
observation times of UTC 200/22:09 to 200/22:27 for event L. The PPR
has a single field of view that is about 4 times the size of
Jupiter. A filter at 945 nm was used for these observations; the
sample time was 0.4 sec.  The L impact was seen at UTC 22:16:48. The
brightness corresponds to about 4 percent of the brightness of Jupiter
itself. The signal rose to peak value in about 2 sec and then
decreased over 35 sec to background levels. The shape of the light
curve was very similar to that seen earlier for event H (item 11-C).
Galileo is positioned to see the impact sites directly, at a distance
of 240 million km; the phase angle of Jupiter is 51 degrees. This
report was prepared by Terry Z. Martin, Leslie K. Tamppari, and
I. Claypool (JPL), and L. Travis, A. Lacis, and J. Hansen (GISS, New
York).

M. L. Kaiser, R. J. MacDowall, M. D. Desch, W. M. Farrell and
R. G. Stone (Goddard Space Flight Center, Greenbelt), on behalf of the
ULYSSES Unified Radio and Plasma Wave (URAP) Team, report 
radio monitoring by the spacecraft Ulysses, which from its vantage
point high over the Sun's southern polar region has a direct line of
sight to the impact areas.  The URAP instrument covers the frequency
range of 1 kHz to 1 MHz with very high sensitivity.  This frequency
range encompasses several of Jupiter's known radio components and
these components are quite regularly and easily detected by URAP.
They have now processed URAP data through the Q impacts and have not
detected any clearly identifiable radio emission associated with the
impacts.  Both Jupiter and the Sun are very active, but not out of the
ordinary.  They will continue to analyze the data in search of more
subtle or long-term effects due to the impacts, but at this stage the
Team is not hopeful that anything will be revealed.

Observations of Jupiter by the Voyager 2 Ultraviolet Spectrometer
began on July 8 and have been continuous except for gaps in downlink
telemetry coverage.  The wavelength range is approximately 50 to 170
nm.  At this time data have been examined that were taken during the
impacts of fragments A, B, C, D, F, G, and H, but no statistically
significant signature from any of these fragments has yet been
identified.  More detailed analysis will follow, and Voyager
observations will continue until 17 August (Bill Sandel, Lunar and
Planetary Laboratory, University of Arizona, Tucson).

13-D. INTERNATIONAL ULTRAVIOLET EXPLORER (IUE)

Walter Harris, for the IUE US science team, communicates the following
summary of recent IUE observations: "Observations of the Jupiter
system have been performed with the IUE satellite on a 24 hour basis
since the July 15, and intermittantly since early June. The IUE
imaging spectrographs have a combined spectral coverage from 1150-3300
A at resolutions from 0.14 to 6A.  We are monitoring several of the
best studied upper atmospheric features of Jupiter and its
magnetosphere including the Aurora, the Lyman-alpha equatorial
anomaly, and the Io torus.  We have detected changes in some of these
features (in particular, the aurora has been weak) that we attribute
to (or at least find suspiciously coincidental with) the effects of
the comet fragment impacts and/or to the passage of dust through the
inner Jovian magnetosphere".

"The IUE is also being used to monitor the development of spectral
features in the impact areas, and in particular has been useful for
showing the timescales that describe the development of the dark
features seen in the WFPC-II images.  The A, B, E, G, K, and Q impacts
have been observed with great success.  For instance, our analysis of
spectra obtained on the approaching and receding limb while we
followed the G impact site with the IUE small aperture show that the
region experienced a 50 percent drop in reflectivity as it moved
across the disk of the planet. Many possible absorption and emission
features have also been observed in spectra obtained from the impact
sites.  We have not as yet had an opportunity to analyze these
features properly.  We are also performing an unprecedented number of
simultaneous observations with other instruments.  This is providing
new insight into the characteristics of features long studied with the
IUE, and gives the operators of the other instruments an opportunity
to compare the results of their observations with the more than 15
years of Jovian FUV spectra in the archives.  Along with our European
collaborators, we will continue to monitor the effects of the impacts
on a 24 hour basis with the IUE until the end of the week, and then on
a less regular schedule until it becomes unobservable with the
satellite on Aug. 15."

Gilda Ballester, for the IUE US-Vilspa observing team: "We report
the likely detection of H-Lyman alpha emission off the Jovian limb
associated with the plume of the impacts of fragments K, and P2 using
the modest imaging capabilities of the IUE satellite.  Although the
resolution (PSF) at Lyman-alpha is 4-5 arcsec, the emission peaks
near/at the limb, and there is also quite extended, weaker emission
within the 9 x 21 arcsec aperture, possibly 3 - 4 arcsec above the
limb.  Some molecular hydrogen emission is also detected (it appears
less extended compared to the H-Lyman alpha, although this could be
the effect of low S/N).  Impacts Q and R have also been observed, but
not imaged with the small 3 arcsec aperture.

13-E. MORE SPECTRAL OBSERVATIONS

It is now apparent that a great quantity of excellent spectra has been
secured at various observatories, and that there is optimism that
future analysis of these data will allow characterization of the impact
sites in quite some detail. Already many molecules are being
identified, as shown by the following examples.

Roger Knacke, Tim Brooke and Tom Geballe have given more details about
the detection of overtone CO emission by CGS4 at UKIRT yesterday evening in
the R impact plume.  These may be helpful to those planning
observations of the final impacts (Hurricane Emilia is lurking off the
coast of the Big Island, and the prospects for further measurements
are somewhat dubious).  They obtained a series of 2.2 -2.4 micron
spectra spaced in time by roughly 1 - 2 minutes, with spectral
resolution 700 and a 1.5 arcsecond wide slit. The entire episode of CO
emission lasted no more than ten minutes. The first spectrum obtained
after the dramatic rise in flux (by approximately two orders of
magnitude) shows a classic 2-0 band profile - a sharp rise at 2.345
micron and a gradual decline to longer wavelengths.  The other CO band
heads (3-1, 4-2, 5-3) are not clearly distinguishable, due to blending
by other emission features (probably CH4 bands).  The subsequent
spectrum, obtained 1 - 2 minutes later is an order of magnitude weaker
and shows the 2-0 band emission profile being cut off at longer
wavelengths.  This is believed to be due to CO 0-2 absorption (by CO
on the outside of the blast which had already cooled). Within another
minute or two, the CO 2-0 emission had disappeared, leaving an
absorption centered at about 2.31 - 2.32 micron. By the time of the
subsequent spectrum, this absorption feature disappeared.

They have also observed an emission line at 2.407 micron during the R
impact.  The wavelength is coincident with the wavelength of an H2O
line.  The observed feature changed to absorption a few minutes after
the peak of the event and then faded away. This mimics the behaviour of
CO lines reported above.  The observation is a provisional detection
of H2O. 

The CO emission spectrum obtained from the R impact fireball at the
Steward Observatory 90-inch has been reduced more thoroughly with the
following results (George Rieke): "We see a bandhead and about 40
emission lines, making the identification as CO totally unambiguous.
There are two possible explanations for the shape of the bandhead.  In
one, the emission band is near zero velocity and there is an
absorption CO feature shifted by about one resolution element (80
km/sec Nyquist sampled for our spectrum) to the red.  The emission
lines become apparent on the other side of this absorption at about
2.295 microns.  The second interpretation would be that the bandhead
is redshifted to 2.295 microns, giving a recessional velocity of about
200 km/sec.  This second possibility seems less likely given the
geometry of the event and the rate at which the fireballs are seen to
expand in imaging experiments.These results appear to be in excellent
agreement with the independent observations with the UKIRT; the higher
spectral resolution of our data complement the greater coverage they
achieved."

Report from IRAM 30-m observations (E. Lellouch, R. Moreno,
G. Paubert, M. Festou): "After the announced detection of CS2 by the
HST team, we have searched for CS in impact sites K, L, Q1 and T on
July 21, UT 16-22.  The CS(5-4) 244 GHz line was detected on site Q1,
with an integrated intensity of 3.2 +/- 0.12 K km/s and a width (FWHM)
of about 4.7 km/s.  The CO 230 GHz was also readily detected on this
site, with similar characteristics as the CS line (i.e. several times
more intense than in previously observed sites E,G,H,K). Data
reduction for other sites is in progress.  We also report unsuccesful
searches on site K (on July 20) for CH3OH and HC3N near 218 GHz."

>From La Silla, G. Wiedemann, T. Encrenaz, R. Schulz and J.A. Stuewe
report: " After further analysis of our IRSPEC-NTT spectra of impacts
E and F (July 18, 2:30 UT) centered at 2.12 microns along the parallel
of the impact sites we now believe that we are able to distinguish
between the two impact regions.  The spectrum of impact F is
characterized by a featureless continuum (which, if thermal, indicates
temperatures of about 1000 K), whereas the already evolved site E
shows little continuum, but strong H2 S(1) line emission."

13-F. LARGE RINGS AROUND IMPACT SITES ?

The HST images of impact sites have shown that they are all surrounded
by dark rings, outlining the perimeter of the impact zone. The effects
of the impacts on the atmosphere have been likened to what happens
when a stone is thrown into water and concentric rings emerge. But
will large, expanding rings be observed in the Jovian atmosphere ?
Three reports have been received about this; one is negative, but the
two others seem to indicate that large rings may have been seen.

Heidi B. Hammel, for the Hubble Space Telescope Team: "At this point
in time (21 July 1994 19:30 UT), the Hubble Space Telescope Team has
not yet seen evidence for any rings other than the small discrete
rings which closely surround the largest impact sites, and the larger
ejecta blankets generally to the south of each feature.  It is
possible that our temporal and spatial sampling is not optimal for
seeing these large scale phenomena.  The G impact created the largest
site yet seen.  Many of the sites (including G) appear larger near the
limb than they do near the central meridian due to enhanced
scattering.  All detected phenomena at impact sites were and still are
bright at the 8890 A methane band.  Imaging was also obtained at 9530,
5550 or 5470, 4100, 3360, and 2550 A (virtually all detected phenomena
at impact sites were dark at those non-methane wavelengths)."

"A very large dark ring is seen surrounding the impact site (L ?)
which moved onto the limb at about 10:02 UT (21 July). The ring
extended beyond the south pole, and nearly to the equator, imaged
using a Bessell blue filter and CCD detector.  The central impact site
was also dark in this filter. Where this ring intersected Jupiter's
dark band at about 20 degrees south latitude (belt? zone?) the methane
image shows a bright spot. The impact site is not bright in the
methane (8900 A, 300 A wide) This complex was seen to move across the
face of the planet in successive images taken between 09:24 and 10:38
UT. By 12:46 UT poor seeing prevented seeing it. This feature was
marginally visible in a narrowband sodium filter, but not in a Cousins
R filter.  These observations are part of the Comet Impact Network
Experiment headed by Steve Larson of the University of Arizona."
(Ellen Howell, at 1-metre telescope, Mount Stromlo Siding Spring
Observatory, Australia)

"Images obtained from Lick using a high speed CCD camera system on 20
July UT confirm the reports of Howell and others from Mount Stromlo
that there is a possible large dark ring surrounding the A impact
site.  We observed the impact sites using a variety of filters
(bandwidth 100 A).  In B images obtained from 04:00 to 05:00 UT (July
20), we observe a large dark arc-like structure extending from the
south pole up to -20 degrees S latitude and centered on the A impact
site (which was also dark in our B images).  The arc has a radius of
roughly 10 arcsec.  The structure is also visible in our U band images
but is not visible in any of our narrowband filters.  There are at
least two immediately obvious possible explanations for this feature:
(1) it may be the visible expression of an expanding shell (or wave)
of material from the A impact site: the feature is large because the A
site is oldest; (2) it may be an artifact introduced by a combination
of 2-arcsec seeing and the fortuitous alignment of the GRS and H
impact site along an annulus concentric to the A site.  In the
exploder report by Howell, the bright spot in the methane filter at
the intersection of the dark ring and Jupiter's dark -20 degree band
is probably the GRS.  Also, the impact site on the dawn limb in the
Howell image is most likely the A site.  Jupiter's aspect was nearly
the same at 04:00 UT on July 20 and 10:00 UT on July 21."  (Jim Bell,
Ted Dunham, Dominique Toublanc and Bob Thompson, Lick Observatory
Crossley 36-inch Observing Team, USA).

13-G. OBSERVATIONS AROUND THE WORLD

The observations of the SL9 event have been made by many different
techniques by many observers, especially now that the effects have turned 
out to be so dramatic that they can be perceived even in relatively 
small telescopes.

We reproduce here a few of the many reports received during the past
night (July 21 - 22). They illustrate the wide geographical
distribution of the observers, now participating in the SL9 campaign.

Casey Lisse, Phil Esterle and Mike A'Hearn for the NASA/IRTF Science
Team report: "We have detected comet fragment K from the NASA/IRTF
(Hawaii) at 2.26 +/- .03 micron with low S/N (signal-to-noise ratio)
on July 19, only 150 to 60 minutes (4.7 to 2.7 Jovian radii from the
planet center), before impact with Jupiter. The fragment appears
extended both along and perpendicular to the direction of orbital
motion. One week earlier on July 12.4 (about 70 Jovian radii from
planet center) we could not detect the same fragment at J band (1.25
micron), when the fragment was near the edge of the Jovian
magnetosphere. We earlier detected fragment K with good S/N, using
similar integration times at both J and K bands in January and May,
1994. Sky levels and noise on July 12.4 were similar to those found in
May; the scattered light from Jupiter dominated the sky background on
July 19, forcing the use of the 2.26 +/-.03 micron bandpass and
background modeling to detect the fragment."

Guy Consolmagno and Gary Menard (Specola Vaticana/Vatican Observatory
Research Group) have found changes in the colour of the Jovian moon
Io: "We observed Io in the evening of July 20 with a 24-inch
Cassegrain telescope at the Specola Vaticana, south of Rome, using a
two-channel photometer borrowed from Prof. Bill Hubbard at the
University of Arizona, from 19:33 UT (end of twilight) to 20:30 UT
(when the clouds moved in), that is at the time of the impact of the
Q-fragment. Light cirrus clouds and somewhat higher humidity than
previous nights.  We haven't analyzed the data yet, but we did notice
by eye increases in the signal at the following times: 19:42 UT: sharp
increase in red and blue; 19:54: slight increase in red and blue;
20:05: slight increase in blue, not red; 20:07: increase mostly in
blue, some in red; 20:19:52: noticeable increase in blue and red, blue
seems to fade faster than red.  All "events" represent fluctuations on
the order of 10 percent increases.  These "events" may just have been
problems such as high clouds scattering light from Jupiter, but the
last event time does coincide with other reported impact times.
That's our last event from Rome; today the rains have arrived."

Yurij Parijskij with RATAN-600 observers (Northern Caucasus, Russia):
"At RATAN-600 site (the 600 metre radio telescope), we are monitoring
daily the thermal radio emission of the Jovian disk (wavelengths 1.3;
2.7; 3.9 cm), the size and flux from Jovian radio emitting belts (7.6;
13; 18; 31 cm) and also decametric bursts at wavelengths 10 metres and
20 metres, not very far from local meridian. At 10 metres, a well
visible burst of activity appeared within 1- 2 min of the time from
object E impact time as it was actually observed (we received this
information by e-mail) and within 5 min from the early prediction by
the Institute for Theoretical Astronomy (Russia). We are now waiting
for confirmation from other observers.  Variations of the belt
radiation also visible (about 10 persent) in horizontal polarization,
but not in the vertical one. Connection with comet-induced fenomena
should be checked later."

"We used the 1-meter telescope at the Vainu Bappu Observatory
(Kavalur) and obtained images on July 18 and 19 through narrow and
medium (100 A) pass band filters (8930 NB, 8900 BP, 6581, 5083, 4935
and 4862 A). The crash spots and the south pole appear very bright in
the methane band at 8930 A.  The crash spots appear dark with good
contrast in the other filters. At the 2.34-meter telescope, long slit
spectra in the region 4900 - 7400 A of the crash latitude were
taken. No obvious changes in the spectrum at the crash spot is
immediately apparent. More detailed analysis will be required to
detect small changes." (Observing team at the Vainu Bappu Observatory,
Indian Institute of Astrophysics, Bangalore, India).

"The impact site of fragment E was spotted at 16:40 UT on July 17. We
were using a 10" Newtonian (mag x200). The viewing was through wide
breaks in low altitude clouds with very good seeing for periods up to
5 seconds. All observations are visual.  A black streak with a slight
N-S extension was seen towards deep South near the following limb. As
it came towards the central meridian (17:45 UT), it had spread out
into a well-defined spot.  The spot apparently had an extension
towards the preceding side (not confirmed). There was a bright white
region immediately to the following side of the site. Estimated area
was 1/5th to 1/6th that of the Red Spot". (Kamal Lodaya and members of
Madras Astronomy Association, India).

"We successfully obtained images of the K and L impact sites at
11:10(UT) on July 20 with the 1.8-metre Bohyunsan telescope using CH4
filters.  We also confirmed the N site with the same telescope, but it
was very weak.  A 20 cm telescope captured the K, L sites without
filters in the visual range.  We could find dark colours on the sites.
Amateur astronomers in Korea also succeeded in finding the L site
using their cameras with small (10 cm) telescopes near Seoul.  On July
19 (UT), we also obtained the image of K impact site with the
1.8-metre telescope using CH4 filters. It was also captured with a 20
cm telescope in Daeduk with a CH4 filter (8900 A) at 11:30 UT." (Bong
Gyu Kim and the Korea Astronomy Observatory Science Team).

13-H. LAST ISSUE OF THIS BULLETIN

This is the last issue of the ESO SL9 Bulletin. At the very moment
when it goes to press, the impact of last fragment is expected to take
place and the dramatic series of events now comes to an end. We have
attempted to document the major developments of this large
observational campaign which involved astronomers all over the world
and has already resulted in enormous amounts of unique data. The
evaluation will soon begin and we shall gradually learn about the new
knowledge won during this international endeavour.  There are already
many signs that exciting discoveries will come to light in the
course of this work.

We would like to close this publication by thanking all those who have
provided us with information and assisted with technical help. It has
often been a rather desperate rush to be ready before the daily ESO
Press Conferences at 11:00 CEST and we would never have managed
without the friendly and efficient support by Baxter Aitken, Claus
Madsen and Erich Siml. We also would like to apologise for the typographical
and other small errors which have appeared due to inadequate time for
thorough proof reading.

The editors: Richard Hook, Olivier Hainaut and Richard West (ESO).

-----------------

This daily news bulletin is prepared for the media by the ESO
Information Service on the occasion of the July 1994 collision between
comet Shoemaker-Levy 9 and Jupiter. It is available in computer
readable form over the ESO WWW Portal (URL:
http://http.hq.eso.org/eso-homepage.html) and by fax to the media (on
request only). News items contained therein may be copied and
published freely, provided ESO is mentioned as the source.


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