Kein Blitz von K / Erste Galileo-Daten / Warten auf Q: Rep. #11 20.7. 2:15 CST ------------------------------------------------------------------------------ Waehrend der Cerro Tololo heute wolkenhalber komplett leer ausging, war man fast ueberall auf der Welt erfolgreicher - inklusive USA-Korrespondentin SH: Date: Tue, 19 Jul 94 23:09:46 EDT From: Susanne Huettemeister Subject: SAW IT!! Wir haben von 8:30 bis gerade vom Dach mit dem 9" Clark Refraktor beobachtet. ES IST TOTAL UNGLAUBLICH!!!!!! Zu sehen waren am Anfang Die Einschlagstellen G/D und L (ganz neu, erst drei Stunden alt), ganz am Ende, als Jupiter schon unterging und das Seeing ganz extrem mies wurde, kam H um den Rand rotiert. Das Wetter war extrem dunstig, man sah Sterne nur bis zur 2. oder hoechstens 3. Groesse, und sehr feucht. Nichtsdestotrotz: Diese Flecken haben nichts, aber auch ueberhaupt nichts "Subtiles" - sie sind BEI WEITEM das Auffaelligste was ich auf Jupiter je gesehen habe, VIEL auffaelliger als der GRF und dunkler als die dunkelsten Baender. In raren Momenten guten Seeings war in den Flecken Struktur zu erkennen, v.a. das ganz dunkle "Bull's Eye" und das, was Heidi H "smudge" nannte. L war fast genauso gross und dunkel wie G. Ist G schwaecher geworden, oder ist L wirklich genauso intensiv??? Alle Leute waren ueberwaeltigt, aber der Grad des Ueberwaeltigtseins hing davon ab, on die Leute Jupiter vorher schon oefter beobachtet hatten. Wenn nein, sahen sie Flecken ohne Probleme und waren erstaunt, erfreut und zufrieden, weil sie nun "wirklich" etwas sahen und nicht bloss auf Bildern (es scheint, dass *jeder* hier das WWW zu pluendern versucht). Leute, die Jupiter voher schon beobachtet hatten, reagierten mit voelligem Unglauben (ich auch): "I can't believe it." --- "wow...!!" ---- "This is totally incredible!" Oder auch einfach nur ein lauter Aufschrei. Diese Features sind derart deutlich zu sehen, dass Radioastronom Tom Dame (erfreulich, dass meine Gruppenleute Tom und Sam von der Begeisterung so angesteckt sind...) sagte: "Well, this is about as easy to spot as sunspots." Er hat recht - seeing oder Focus ist kaum ein Faktor - man schaut mal kurz hin und sieht die Flecken auf den allerersten Blick. Natuerlich ist ein 9" Clark-Refraktor ein tolles Instrument, aber ich bin ueberzeugt, dass man die Flecken in einem 3" oder 4" Teleskop bei ordentlichem Wetter nachweisen kann. Jedes Teleskop, das irgendwas auf Jupiter zeigt, wird sie zeigen. Noch gestern habe ich gehoert, wie Leute bei den Pressekonferenzen auf Fragen, ob denn auch Amateure.... sehr vorsichtig meinten: "Na ja, mit Erfahrung und bei gutem Himmel..." Falsch. Nichts Subtiles an den Flecken. Das am deutlichsten sichtbare Phaenomen auf einem Planeten, das ich je gesehen habe. Bevor einige weitere Amateure zitiert werden sollen, erstmal 'richtige' Wissenschaft: Galileos erste Daten sind soeben zur Erde getroepfelt! First direct impact observations: Galileo PPR results for Events B and H The Photopolarimeter Radiometer on the Galileo spacecraft observed Jupiter for 41 minutes during periods corresponding to earthbased observation times of UTC 198/02:22 to 198/03:03 for B and UTC 199/19:11 to 199/19:52 for H. 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. No evidence of the B impact was found. The H impact was seen at UTC 19:31:59. The brightness corresponds to about 2% the brightness of Jupiter itself. The signal rises to peak value in about 2 sec and then decreases over 25 sec to background levels. Galileo is positioned to see the impact sites directly, at a distance of 240 million km; the phase angle of Jupiter is 51 degrees. Terry Z. Martin, Leslie K. Tamppari, and I. Claypool JPL L. Travis, A. Lacis, and J. Hansen GISS, New York Und das Kuiper Airborne Observatory ist gelandet, mit ueberraschenden Spektren: The KAO has just landed in Melbourne, Australia, after observing methane emission from the K fragment at 7.7 microns at a resolution of 9000. It was even more spectacular than the G fragment. At approximately 10:39 UT, the signal soared to roughly 25 times the brightness observed 10 minutes earlier. The fireball appeared in 2 of our spatial pixels, implying that its spatial extent was at least 5", and possibly as large as 10". Interestingly, we also noticed some bright spectral features which are probably not due to methane, and are at this point unidentified. We again observed at 22.6 and 23.9 microns to look for water vapor, but decided to wait until the fireball dimmed considerably. Data analysis is in progress on the water vapor observations, but at first glance, there was no evidence for Jovian water. Gordon Bjoraker (NASA GSFC) Terry Herter, Susan Stolovy, Bruce Pirger, George Gull (Cornell) Und erdgebundenen Beobachtern (auch dem HST) ist es gelungen, noch nach Beginn der Einschlagsserie die spaeteren Kometenfragmente direkt abzubilden: Date: Tue, 19 Jul 94 14:47:38 HST From: David Jewitt Optical Imaging of Fragments from Mauna Kea We have obtained R-band coronagraphic images of fragments of comet SL9 inside the Jovian magnetosphere. We used the University of Hawaii 2.2 meter telescope on Mauna Kea under sub-arcsecond seeing conditions. Observations were taken UT 94/07/19.2 - 19.3 using coronagraphic optics. Fragments P2, Q1, Q2, S, R and W were detected at high signal/noise ratio. Fragments N, P1, T, U and V were beneath our detection limit, while L fell outside the fields of view employed. Images of fragment K were obtained 2 hours prior to impact. Astrometry has been communicated to Paul Chodas et al, for all observed fragments except K. The non-appearance of V is surprising, based on its pre-entry brightness (comparable to W). The fragments now resemble aligned tadpoles, with the tails pointing towards Jupiter along the axis of the comet string (i.e. the tadpoles are falling into Jupiter tail-first). We see no evidence for the radiation pressure-swept dust tails that have dominated the morphology since early 1994. The tadpole morphology is most pronounced for Q1 and S, but is probably present in all nuclei. Our images presumably trace the distribution of large "dust" or boulder-sized solids that are immune to scattering by the Lorenz force. Preliminary photometry provides no evidence that the central (1 arcsec) cores of the fragments have faded since immersion in the magnetosphere, although further work will be needed to clarify this point. David Jewitt and Paul Kalas (University of Hawaii) Viel Beachtung hat folgende Einschaetzung Clark Chapmans des G-Impaktortes gefunden - das Relevanteste, das je auf Jupiter beobachtet wurde... I want to put this into the historical context of Jupiter observations. It is now about 5:30 UT, 19 July. I have just come in from looking at Jupiter with my back yard telescope. (Our team will again be on the Kitt Peak 2.1 m telescope three evenings from now.) The preceding end of impact site G is approximately on the central meridian. Based on my own extensive experience of observing Jupiter when I was younger, and studying historical records of Jupiter observations from the early drawings of Hooke and Cassini through the extensive 19th and 20th century reports of the British Astronomical Association, I would assert: THIS IS THE MOST VISUALLY PROMINENT DISCRETE SPOT EVER OBSERVED ON JUPITER. (By "prominence" I mean the combination of both size and contrasting albedo.) Does anyone disagree? Clark R. Chapman From: Jason Regier Date: Tue, 19 Jul 1994 01:00:29 -0700 (PDT) Here at the Table Mountain Observatory, I observed the impact site of fragment G on the 24 inch telescope through a red filter (approximately 570-700 nm) using a Sony SSC-M350 CCD video camera. I first observed the incredibly large, dark spot rising over the limb at approximately 4:26 UT. In a 200 frame movie of 3 second exposures, I watched from 4:56 UT to 6:44 UT as it crossed the central meridian. The impact site seemed to cross the central meridian at approximately 6:06 UT and was at least 16,000 km in diameter. The spot also may be somewhat extended in the east-west direction, but this may be only an optical illusion arising from the site's relatively low latitude. Jason Regier and the TMO Team Date: Tue, 19 Jul 94 19:54:48 EST From: Vikki Meadows AAT IRIS Observations of the Impacts of Fragment G of Shoemaker-Levy 9 with Jupiter David Crisp, Vikki Meadows, Stuart Lumsden, Jonathan Pogson, and Steven Lee The InfraRed Imaging Spectrometer (IRIS) is being used on the 3.9 m Anglo-Australian Telescope (AAT) at Siding Spring Observatory (near Coonabarabran, Australia) to monitor the impacts of the fragments of Comet Shoemaker-Levy 9 with Jupiter. On 18 July, observations of Jupiter were initiated at 6:30 UT, about one hour before sunset. The skies were clear, and the seeing was better than 1 arc-second. Near-infrared images and spectra at wavelengths between 2 and 2.4 microns taken between 6:30 and 7:30 UT on 18 July 1994 revealed two bright features near the evening terminator at about 45 South latitude. These features were identified as the impact sites of fragments A and C, which had been monitored on the previous day. Bright flashes associated with the impacts of fragments G2 and G1 were first detected on the morning limb of Jupiter at 7:33 and 7:40 UT, respectively. The impact flashes were tens to hundreds of times brighter than those seen previously. These sites were monitored until 13:30 UT. [...] The Evolution of the Fragment G Impact Sites: IRIS K-grism cubes revealed a faint flash on the morning limb of Jupiter at 7:33 UT. This feature was initially much dimmer than the C-impact site, which was still on the evening limb of Jupiter. The brightness of this feature increased by about a factor of 10 by 7:35 UT and remained stable until about 7:40 UT. At that time, the morning limb suddenly brightened dramatically, saturating the detector and producing a brilliant star-like image with diffraction spikes. [Anm. DF: Diese Aufnahme, die noch vor dem Quasikollaps der Kommunikationsverbin- dungen wegen akuter Ueberlastung durch Kometenimpaktbildsucher den C.T. erreichte, ist wirklich die bisher spektakulaerste und duerfte als *das* Bilddokument in die Astro-Geschichte eingehen. Dabei ist das Keck-Bild vom G-Impakt eigentlich viel besser (technisch) - aber die Beugungsstrahlen geben ihm einen ungeheuer gewaltigen Touch. Kurioserweise hat El Mercurio heute ein noch viel unschaerferes Bild vom SPIREX auf dem Cover.] To bring the detector back on scale, the 3.9 meter AAT mirror was partially closed, reducing the effective aperture of the telescope to less than 1 meter (less than one tenth of its full size). After 8:10 UT, the G impact site had rotated onto the Earth-facing hemisphere of Jupiter, and its surface brightness at wavelengths near 2.34-microns decreased to about 12 times that of the south polar hood. The size of the feature was comparable to that of the Great Red Spot. Unlike the impact sites of the earlier fragments, the G impact site was visible at all wavelengths where observations were collected. It was even visible in the TV camera that was being used to guide the telescope. This TV camera employed a spectral filter centered at 0.55 microns, and revealed the impact site as low-contrast dark spot with dimensions comparable to those seen at 2.34 microns. A similar feature was seen in IRIS images taken at 1.083 microns. IRIS H-grism images taken within the 1.7 micron methane band showed a 15000 km diameter bright feature surrounded by a dark apron, which had about twice that diameter. IRIS K-grism images taken within the strong methane bands near 2.34 microns resolved the site into a double-lobed feature. Hubble Space Telescope observations suggest that the second smaller component of this feature may have been associated with the impact site of fragment D, which was monitored on the previous evening (Heidi Hammell, personal communication, 1994). Peter McGregor and Mark Allen used the CASPIR infrared camera at the 2.3 m Australian National University Telescope at Siding Spring Observatory to acquire observations at wavelengths between 3 and 4 microns. At these wavelengths, they detected a bright spot 2000 to 3000 km in diameter, surrounded by distinct 30,000 km diameter bright ring. [...] Inferences about the Wavelength Dependence and Nature of the Impact Features We have not yet had time for a detailed analysis of the IRIS near- infrared spectra of the impact sites, but a quick review has revealed no distinct spectral features. This result, and the summary of the wavelength dependence of the impact features presented above provides some constraints on the albedo and composition of the the impact debris. The evidence can be summarized as follows: At most visible wavelengths, and at near-infrared wavelengths outside of strong methane bands, where the Jovian disk is relatively bright, the impact sites are invisible or they appear slightly darker than the background clouds. The albedo of the impact sites may be decreasing somewhat with time at these wavelengths. Within strong methane bands, the impact sites appear bright. At the longer wavelengths, the brightness of the methane-band features decays rapidly during the first hour after the impact event, but then stablizes to produce a long-lived feature. These characteristics suggest the following preliminary interpretation. The impact events include a strong thermal component as well as a component due to sunlight reflected from the impact plume. The thermal component is most obvious at the longest wavelengths, but decays rapidly as the impact plume expands and cools. Once the impact site rotates onto the Jovian disk, the observed features could be produced by a high-altitude cloud consisting of material that has condensed from the impact plume. The reflectivity of this cloud material appears to be comparable to, or slightly lower than that of the main cloud deck at wavelengths outside of strong methane bands. Because of this, the impact sites are invisible or slightly dark at these wavelengths. The albedo of the impact sites may decrease slightly with time. The impact sites appear bright at methane-band wavelengths because the cloud is above the majority of the methane gas which absorbs sunlight and reduces the reflectivity of the Jovian disk at these wavelengths. The available observations suggest that the observed spectral behavior at wavelengths less than 3 microns might be explained if the cloud material has a moderately-bright, spectrally-uniform albedo. Sophisticated radiative transfer models of the Jovain atmosphere will be needed to confirm this speculation. The relatively high albedo of the impact features at wavelengths near 3.1 microns appears to rule out several candidate impact cloud materials, including water ice, which is very dark at these wavelengths. The central spot and the ring-like structure that is most obvious at wavelengths longer than 3 microns might require a more complicated explanation. Several possibilities immediately come to mind. The central spot could be produced by intense heating at the impact site, or by the most optically-thick region of the impact cloud. The ring could be caused the heating or chemical reactions associated with the splash-back of material carried upward by the impact plume. Alternatively, this feature could indicate the presence of a traveling wave, like a ripple produced when a stone is thrown into a pond. It should be possible to discriminate between these mechanisms by measuring the size of this feature. The diameter of a traveling wave is more likely to increase monotonically with time, while the diameter of a splash-back ring should not necessarily vary in a systematic way. Nun aber zu den Beobachtungen des K-Impakts in der vergangenen Nacht, von dem man sich ja einen klaren Lichtreflex auf Juppis dunklem Mond Europa erhofft hatte, und der im fernen Osten und Pazifikraum gut zu sehen war: report from Okayama Astrophysical Observatory. We just observed the plume of nucleus K with Near-IR camera attached to 188cm telescope at Okayama Astrophysical Observatory, National Astronomical Observatory of Japan Initial flash was detected at 10:25 UT on July 19. This is fainter than Io, and its brightness decreased rapidly. Then the brightness increased again around from 10:31 UT, reached maximum around 10:38 UT. The maximum brightness is roughly 20 times or more of the brightness of Io. Several ND filters were used during the maximum phase in order to keep the signal within the effective range of our detector. These are all in 2.36 micron images. Fragment K - no optical flash, yes optical cloud CCD images were obtained with an R filter from Perth Observatory with 3-second exposures and about 2/3-second dead time covering Jupiter's limb, Io, and the expected position of Europa (in eclipse) from Jul 19 10:00 UT to Jul 19 10:30 UT. Io was completely saturated. In the raw data there was no hint of a flash reflected from Europa, nor was there any flash at the limb of Jupiter. Starting at Jul 19 10:35 UT, images with a narrow methane absorption filter at 8930A showed a definite prominence above the apparent limb of Jupiter, having approximately the same surface brightness as other portions of that latitude belt. Note that this is probably already on the front side of Jupiter as the limb in the continuum is well above the limb in the strong methane filter. This suggests that condensation occurs very rapidly after the fireball is ejected. The impact of fragment K was recorded in clear skies by CASPIR on the ANU 2.3 m telescope at Siding Spring Observatory. No reflected emission was seen from the satellite Europa. The first indication of a plume was detected at UT 10:21:22 at 2.34 microns. Shortly after, at UT 10:24:33, a bright fireball was detected The K impact site remained at constant brightness until UT 10:31:40 when an intense central core brightened sufficiently to cast diffraction spikes across the array. As the impact site rotated into view the fireball increased in brightness rapidly. By UT 10:33:02 we estimate that it was slightly brighter than the peak brightness of impact G observed yesterday. Observations at 4.78 microns beginning at UT 10:48 show a bright region at the impact site. Images at wavelengths between 3 and 5 microns show a wave moving out from the impact site, similar to that detected by us for impact G. Observations continue. IMPACT OF FRAGMENT K OBSERVED BY IRIS ON THE AAT We are continuing to use the InfraRed Imaging Spectrometer (IRIS) on the 3.9 m Anglo-Australian Telescope (AAT) at Siding Spring Observatory (near Coonabarabran, Australia) to monitor the impacts of the fragments of Comet Shoemaker-Levy 9 with Jupiter. On 19 July, observations were initiated at 06:00 UT, and continued until Jupiter reached the zenith limit of the telescope (13:20 UT). The sky was clear, and the seeing was near 1 arcsec. At the start of observations, the impact sites of fragments G, H, F, E, and A were clearly visible as bright clouds at K-band wavelengths within strong methane bands. These features were also visible as dark features on our guiding TV, which was using a 0.55 micron filter. The impact flash of S-L 9 fragment K was first detected on the morning limb of Jupiter at 10:24 UT. There was no evidence of the predicted reflection from Europa, which was in eclipse, but visible from the Earth. Images extracted from IRIS K-grism cubes at wavelengths near 2.34 microns revealed an initial flash whose intensity was comparable to that of the fragment G impact flash observed at 7:40 UT on 18 July. The K impact flash reached its maximum brightness at 10:33 UT, when it was about 400 times as bright as the south polar hood. The brightness of this impact site then decreased to about 10 times that of the south polar hood within about 20 minutes, as it rotated onto the disk of Jupiter. The apparent size of the impact site at 2.3 microns was comparable to that of the Great Red spot. The K impact site was also seen as a dark feature at visible wavelengths in the TV guiding camera. Und dann kam schon L - waere hier perfekt zu sehen gewesen...: Whately Observatory reports the detection of the infrared flash from Fragment "L" beginning at 22:17UT. The detection was made with the NICMASS camera through a 2.23 - 2.29um filter. More details to follow. We report the observation of impact L at 10 microns with the CAMIRAS camera mounted on the Nordic Optical Telescope at 22 24 UT. About as brigth as H impact, may be even bigger!. Timeline of Calar Alto Observations of the L impact. Images: 2.3 um, Spectra: 2.0-2.4 um. UT 22:14 Initial detection of L impact UT 22:16 L spot begins to brighten rapidly UT 22:18 L impact six times as bright as K spot UT 22:23 Start of Spectroscopy: Strengthing emission lines at 2.3-2.4 microns UT 22:36 Very strong emission lines=20 UT 22:38 Emission lines decreasing in brightness UT 22:43 Emission lines significantly weaker UT 23:02 End of observations; Jupiter too low to observe The L impact site was observed in daylight at 00:30 UT Jul 20 from the Steward Observatory 53 cm telescope visually with no filter, through light clouds. It appears to be similarly dark and the same size as the G impact site observed 19 hours earlier. Mark Sykes - der sich auch Gedanken zur oeffentlichen Wirkung macht: On July 19 05:30 UT the G impact site was easily seen from central Tucson Arizona through telescopes of modest aperture (20 cm) and I have been told that it was seen through 10 cm telescopes. Through the 53 cm Steward Observatory telescope on campus, the G impact site was observed with no filter and was startlingly obvious and black. As a community we need to take full advantage of this remarkable event and its visibility and encourage the public to look at it through their own telescopes (of sufficient aperture) or go down to their local planetarium or public observatory to look at it. It is not often that we have an opportunity to share with the public such an exciting event in a very direct manner. I want to second Mark Sykes' call for encouragement of public involvement. We must also encourage the scientific value of amateur astro-photography. Amateurs will be able to compiule a much more continuous record than large telescopes can manage over months or years (?!). It would be interesting to pursue the color evolution of the stratospheric hazes from the impacts, since they may provide nucleation sites for hydrocarbon chemisty. Who knows, maybe we can learn something about the famous and enigmatic chromophores from the record compiled by amateur astro-photographers? - Tim Livengood, from a very cloudy and gray ESO La Silla Hier einige weitere detaillierte Amateurberichte aus u.a. England: Observations just completed, with the 30 cm refractor at Cambridge, showed five sites. Site A is obviously fading, and E,A,C are no longer evenly spaced as they were in the July 17 Hubble image. They transited on July 19 at UT 19.44, 20.23, and 21.31 (+/- 2-3m). Here are our System II longitudes, compared with those reported by Pic du Midi on July 17: Cambridge Pic du Midi Chodas July 19 pm July 17 pm pred. ----------- ---------- ------ H Near p. limb - E Looks exactly like a sat. shadow: 83 75 79 A Large but faint - has faded: 107 110 107 C Small dark core? (Lo-res): 148 147 147 K Large & dark like G yesterday (Lo-res) - Seems that E is retrograding. (I will work out System III as well to compare with others' reports, soon.) Mark Sykes will be pleased to know the 'public involvement' was heavy; we were glad to show the the scars on Jupiter to lots of visitors, though it did compete with serious observations! John Rogers, with James Lancashire and Jonathan Shanklin. Und in sci.astro: I just saw a dark smudge! First sighted at 9:50 PM (Jul 19 4:50 UT) near the limb at about the 1 o'clock position in an inverted image. (Near where the impacts are supposed to be happening). This was with a crappy 60 mm scope! Yes, a beat-up Department-store trash job that is at least 15 years old!! Donald Arseneau asnd@reg.triumf.ca Started looking at dusk, 20:20 PST =3D=3D 3:20 UT. Good seeing tonight, full aperture at 360X. 21:18 =3D=3D 4:18 UT July 19, first noticed a huge dark feature emerging from the limb at about 60 South. It looked like the first bite of the umbra during a lunar eclipse. By 21:25 =3D=3D 4:25 UT, the feature was detached from the limb. Last sketched at 21:49 =3D=3D 4:49 UT while Jupiter was fading rapidly through coastal low clouds. It was about the size of the great red spot but much further south, and gray. It looked like a bruise on an apple. I think I saw the impact site of fragment G after two rotations. The timing is a bit late, though. I wish I could have stayed for another hour. It must be an awesome sight at transit. --Pierre Asselin, Santa Barbara, California I and 8 others saw a large sooty black feature in the southern hemisphere whilst observing yesterday. Using 12 in and 8 3/4 in reflectors (sorry don't have the full details with me) as part of a party viewing from the Derby and district astron soc. observatory (some 10 miles wnw of Derby) acquired Jupiter in the daylight at approx 2025 BST, using a polarizing filter to improve visibilty of details. We noticed the feature which in our estimation was 'blurred' to a size easily comparable to the great red spot. We followed it's motion across the planet till it's disappearance at the limb around 2230 BST at which time two observers believed they could see a much fainter black feature of smaller size than the first at the same latitude coming into view over the limb. INTERNET: N.T.Clifford Observing at helensvale, Queeensland. with 30cm Newt. and 35cm Newt. at 200X. At 8:18 pm (10: 18 UT) nothing seen, and no flash from Europa. At approx. 8:31pm AEST, (10:31 UT), observed a similar bright spot (plume?) to the one that we observed last night. However, tonights plume located was on the following limb of Jupiter at about 50 to 55 degrees south lat. It appeared to be fainter than the fragment G plume, and persisted until about 8:45 pm (10:45 UT.) Greg Bock, Peter Marples. Southern Astronomical Society, Queensland, Australia. Members of the Southern Astronomical Society have been observing the impact of fragment K into Jupiter. The observations were made between 10 hrs UT and about 13.30 hrs UT. Observations were made difficult due to poor seeing and the lower altitude of Jupiter as=20 compared to the fragment G impact observations which our group made yesterday. Plume: At 10.30 hrs UT (20.30 hrs Australian Eastern Standard Time), a plume was observed projecting from the southwestern (IAU convention) edge of Jupiter. It was visible until 10.40 hrs UT. The plume was observed by all observers listed below except Peter Adam, president of the Southern Astronomical Society who couldn't get access to a telescope (they were full of observers!!). Indentation: At 11.07 hrs UT, an indentation was observed at the southwestern limb of Jupiter which was similar to the indentation observed for plume G. Although visible, the indentation was much more difficult to observe. The indentation gradually disappeared and was no longer visible by about 11.35 hrs UT. Spot K: During the disappearance of the indentation, a dark spot became visible near the southwest limb of Jupiter. Its appearance, initially, was difficult to discern - it was a dark spot several arcseconds in diameter. By the end of the observing session, it was clear that the spot was composed of a dark centre and a dark ring or collar. [Nach Beobachtungen von 9 Personen mit 32cm-Newton] Nun aber zurueck zur Wissenschaft: Waehrend die Impaktserie noch andauert, gibt es bereits erste detailliertere Auswertungen, z.B. von HST-Spektren: JUPITER: DETECTION OF S2 AND H2S For the Hubble Space Telescope (HST) observing team, K. S. Noll, Space Telescope Science Institute, reports the following results: Ultraviolet spectra of the central 0."9 of impact site G obtained with the HST Faint Object Spectrograph (FOS) on 18 July 1994 show a series of strong absorption bands from 2550-2930 A that we unambiguously identify as S2. A second strong absorption occurs between 1800 and 2300 A caused by a combination of enhanced NH3 and at least one other molecule. The absorption cross section of H2S provides a good match to the spectrum, which we regard as a tentative identification. The absorption bands are observable in both I/F and in ratios of the impact site spectrum to the spectrum of the same location obtained on 14 July 1994. The spectral resolution of the FOS for an extended source observed through the 0."9 aperture is 4A from 1600 to 2300A and 6A from 2300 to 3300A. We note that enhancements of NH3, H2S and S2 could result from heating and vaporization of the NH4SH and NH3 clouds. If sulfur were cometary in origin, we would also expect enhanced abundances of oxygen- and carbon-bearing compounds to be detected. G Impact Site -- Observed at Lick 120" Shane Telescope July 19, 1994, und zwar mit einer Speckle-Bildrekonstruktionsmethode Images of the G impact site as it crossed the face of Jupiter on its third rotation were taken using the high resolution speckle imaging camera at 550 nm last night between 04:04 and 07:00 July 19 UT. These data will later be processed into a movie showing evolution of the impact region over a 3 hour period. With the speckle camera and the bispectral reconstruction technique, high resolution features, about 0.2 to 0.3 arcseconds, are discernable. The G impact central dark spot, the old D spot next to it, and the large crescent of dark material around it are visible. Claire Max, Don Gavel, Erik Johansson, LLNL Mike Liu, UC Berkeley Bill Bradford, UC Santa Cruz Von unserer USA-Korrespondentin auch News der gestrigen NASA-PK: Natuerlich wurden die beiden Bilder vom G-Impakt von gestern (Plume ueber dem Planetenrand und auf der Oberfl"ache) gezeigt - von H haben sie noch nichts. [...] * Sehr verwirrend ist, dass sowohl das HST als auch andere Spektrometer bislang kein auffaelliges Wasserfeature nachweisen koennen. Das widerspricht eklatant Modellen, die starke Wasserlinien vorrausgesagt hatten, weil sowohl Komet als auch tiefe Jupiter-Atmosphaere dazu beitragen sollten. * HST-Spektra zeigen dagegen einen generellen Helligkeiteinbruch und grosse Mengen von Ammoniak. Instantan-Interpretation: Der Impakt hat die NH3- Wolkenschicht bei <=1 bar Druck erreicht und Material nach oben gerissen. Das entspricht den Erwartungen. Allerdings hatten Modelle auf NH3 und Wasser besierend (wenn "uberhaupt) neue *weisse* Flecken vorhergesagt. Warum die Flecken visual schwarz sind, ist noch immer unklar. Natuerlich fuehrt das Aussehen zu unvermeidlichen "puns": "Jupiter's black eye", "It really looks beaten up, and I feel kind of soory for it", "bruises" and so on... * Zitate vom S"udpol: "G was *very* bright" - und auf der "human interest" Seite: "We really advertised G impact, and 8 people come out to the telescope to watch it. It was great fun, and for the time the whole station experienced a feeling of belongimg together." Am Suedpol koennen sie Jupiter (12 Grad hoch) 24 Stunden am "Tag" beobachten (Polarnacht!) * Das Mac Donald Observatory pr"asentiert ein Bild, auf dem 4 Impaktstellen gleichzeitig zu sehen sind. * Nur vom AAT lag ein Bericht vor, nachdem der G-Impakt doppelt war (G1 und G2 in 7 Minuten Abstand). * Ein Mensch vom IUE tauchte im letzten Moment und im Laufschritt auf, und berichtete atemlos, dass sie die G - Site im UV erfolgreich beobachtet haben: Eine klare zeitliche Veraenderung sei zu sehen, die erlauben wuerde, die Dynamik des Ereignisses ("uber ein paar Stunden) zu rekonstruieren. Etwas mehr Radioastronomie, wiederum aus dem SL-9-Mail-Exploder Maryland: Following our detection of CO at impact site G and probably H on July 18, we have continued to monitor the CO 230 GHz emission. Re-examination of our observations of July 17 also reveals that this line was present at impact site E and marginally at impact site C. The following table summarizes the line area for several impact sites and dates. In brackets is the approximate age of the impact sites. "marginal" indicates a marginal detection from which no reliable estimate of the area can be derived. Impact \Date July 17 July 18 July 19 site (UT around 19.00 in each case) C marginal - - (age=3D 12 h) =20 E 0.6 K km/s - marginal (age=3D4h) (age=3D52 h) G - 1.5 K km/s 1.6 K km/s (age =3D 12h) (age=3D36h) H marginal 0.35 K km/s 1 K km/s (age =3D 2 h) (age=3D 26 h) The width (FWHM) of the clearly detected lines is constant at 2-3 km/s. Finally, we have also searched unsuccesfully for CO+ and H2S.=20 E. Lellouch, M. Festou, G. Paubert Und mehr Spektroskopie-Auswertungen auch wieder vom CTIO, diesmal 4-Meter: OSIRIS spectra of impact site E near 2:30 UT on 7/18 taken at the CTIO 4-meter show prominent CH4 absorption lines at 2.20, 2.30, and 2.32 microns, allowing an estimate of the cloud altitude from the CH4 abundance above the cloud layer. We made model spectra between 4300 and 4700 cm-1. The model includes CH4 absorption and solar reflection, and the basic model is similar to that of Kim et al. (Icarus, v. 91, p. 145, 1991). We found that the cloud deck should occur around 2 mbar level, assuming a normal CH4 mixing ratio in undisturbed Jupiter. However, since the explosion would bring up low altitude CH4 to high stratosphere where CH4 mixing ratio is lower, the 2 mbar should be the lower limit of the cloud deck altitude. Usually NH3 cloud occurs at the 300 - 600 mbar level, and the polar haze occurs at the 10 - 20 mbar level. No observations from here today, and yesterday we only obtained a single 2.3 micron image, at 00:05 on 7/19, during a 10-second (!) break in the clouds. This image showed sites C, A, E, and H, with A still very prominent after 52 hours, but much less bright than E and H. [Tolles Bild trotz allem!] Hope for better weather tomorrow... John Spencer, Darren Depoy, Sang Kim, OSIRIS, CTIO 4-meter. Auch weitere Auswertungen auch der Spektren des 1.5-Meter-Teleskops hier: We observed the southern H3+ aurora at UT 1:30 July 18 in order to measure any difference in H3+ temperature after several impacts. At that time B and D impact sites were visible, and it was ~1 hour after the F impact. We used the IRS on the CTIO 1.5 m telescope with a spectral resolving power of 1600. The covered spectral range is 2700 - 3000 cm-1. We found a rotational temperature of 1000 +/- 100 K, which is very close normal auroral H3+ temperatures measured last several years. This result suggests that the SL9 impacts might not make significant influence on the auroral activity. Sang Kim, Christophe Dumas, Jay Elias, Richard Elston. Und zum Abschluss dieses mal wieder ueberwiegend aus verbatim zitiertem Fremdmaterial (besonderes Lob dem Mail-Exploder - 300 KByte in 4 Tagen...) komponierten Berichts (fuer Bearbeitungen bleibt bei der Materialfuelle plus Jagd nach neuen Bildern im ueberlasteten Netz [auch die meisten Laser- printer pfeifen hier auf dem letzten Loch...] kaum Zeit) noch ein Kuriosum: Article 64458 of sci.astro: From: Pieter Kuiper Subject: Re: What if the initial discovery hadn't happened? Date: Tue, 19 Jul 1994 09:57:52 +0100 Organization: Uppsala University In article <30enid$g8q@samurai.ics.com>, dbrooks@ics.com (David Brooks) wrote: > What if the Shoemakers and Levy had gone home early that night (as it > were), and had missed the comet? Is it certain that it would have been > noticed before Saturday by some other routine observation? Yes. Actually, it had been observed a few days before by an astronomer here in Uppsala. However, it looked funny, and he thought that it might be a scratch on his film (all those fragments). So he decided to look again a few days later. But then it had already been published by the Shoemakers. :-( Pieter Kuiper Physics Dept. Uppsala University So kann's gehen (uebrigens gab es kurz danach noch mehr unabhaengige Entdek- kungen), in diesem Sinne (weiter auf besseres Wetter hoffend - mittlerweile regnet und stuermt es auf dem kalten Cerro Tololo) Euer Daniel Fischer