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During the period 16-22 July 1994 we have collected photometric observations of Europa and Io at the Serra La Nave (SLN) Station of Catania Astrophysical Observatory.
High speed photometry at 0.1 and 1 sec integration time was performed with a 91-cm Cassegrain telescope equipped with a photon counting photometer provided by a cooled photomultiplier.
A preliminary analysis of the observations shows that:
16 July (0.1 sec int. time): EUROPA shows a small V band brightening at 19:57:30 UT about 20 min before the first appearence of the plume in the SAAO images of the A impact.
20 July (1 sec int. time): IO shows an increase of the B light at 3 different UT times.
NO detectable brightening was contemporarily measured in V band. The time of the brightening in B band are:
19:41:04 UT
20:18:32 UT
20:29:46 UT
It is worth saying that the Q family impacts were detected by different observers at around 20:19 UT (from SAAO at 20:19, and from Pic du Midi at 20:13 and 20:19 UT)
Giuseppe Leto, on behalf of the SLN "SL9 photometry" observing team: C. Blanco, Astronomy Institute of Catania University G. Leto, Astronomy Institute of Catania University D. Riccioli, Astronomy Institute of Catania University
More information and comments can be obtained from gleto@astrct.ct.astro.it