Astronomical research comprises a curious mixture of team work and individualism. From the hardware point of view data are ends in themselves, while from a strictly scientific aspect their acquisition is but the first stage in the complicated process of building astrophysical models. This dichotomy is reflected in a polarization of attitudes regarding the handling of observational data, and the activity of creating archives of astronomical data for use by posterity has consequently tended to fall in no-man’s-land. To the technology team, a telescope that can successfully deliver a data-bank full of raw observations has achieved its specification, while to the scientist who is under pressure to publish papers on fresh science, the concept of voluntarily creating public archives out of data originating from personal ideas may seem more than a little alien. Nevertheless, the formation of useable and efficient archives of astronomical observations is an activity that has taken on new meaning with the advent and monopoly of digital detectors; it is a procedure that builds bridges as well as access routes and it opens new global perspectives for astronomical data, but it still relies too heavily on individual initiatives.

During the impact of fragment L filtergrams of high spatial and temporal resolution were obtained in the methane band centered at 892 nm with the solar vacuum tower telescope (VTT) located at Izaña, Tenerife. The VTThas an aperture of 0.70 m and a focal length of 45 m. Images were taken every 20 s in the prime focus with a CCD camera operated in 512 х 512 pixel mode. One pixel corresponds to 0.175 arcsec. The spatial resolution varied between 0.5 and 1.5 arcsec due to seeing effects. The exposure time was 2.5 s. At 22:20:52 UT, four minutes after the impact time based on Galileo images, a first brightening above the dark southeast limb of Jupiter was recognized. A first maximum was reached after five minutes. The subsequent decline of brightness was interrupted at 22:31:52 by a sudden bright flare with a lifetime of 90 s. Within our resolution the two recorded emission features are cospatial. The flux of this flare was (3.4 ± 0.2) х 10-4 of Jupiter’s total flux at this wavelength. The feature became almost invisible 19 minutes after its first detection. At 22:43 UT, 26 minutes after the impact, a new brightness enhancement rotated into view which could be identified with the dark impact signature (debris cloud) observed in the visual wavelength range.

Jupiter’s microwave emission was observed throughout the SL9 impact period by many different telescopes, among which the NRAO 140-foot telescope in Green Bank (21 cm), Westerbork (92 cm), Effelsberg (6, 11 cm), Parkes (21 cm), NASA DSN (13 cm), and the Very Large Array (22, 90 cm). We determined the “average” total nonthermal flux density from the planet after having subtracted the thermal contribution, following the formulation by de Pater and Klein, (1989) and Klein et al., (1989). The flux density increased typically by 40-50% at 6 cm wavelength, 27% at 11-13 cm, 22%at 21 cm and 10-15% at 90 cm. Thus the radio spectrum hardened considerably during the week of cometary impacts. Following the week of cometary impacts, the flux density began to subside at all wavelength.

VLA images show the brightness distribution of the planet; a comparison of images taken before and during the week of impacts show marked changes in the brightness distribution. At a central meridian longitude λIII≈ 110°, the left side of the belts increased considerably and moved inwards by ~ 0.2 RJ. This suggests that the increase in flux density is caused by energization of the resident particle population.