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A. Cacciani, P.F. Moretti, M. Dolci (Univ. La Sapienza di Roma), C. Giuliani (Oss. Astronomico "V.Cerulli" di Teramo), P. Patriarchi (Oss. Astrofisico di Arcetri)
An increasing interest has been devoted in recent years to the seismology of Jupiter and Saturn, as it is an intermediate case between the Sun and the stars. Besides the theoretical modelling, few observations have been carried out so far. An instrument, currently used in Helioseismology, has been adapted to deal with the low photon flux from the stars. It is based on the Magneto-Optical Filter (MOF), which provides two narrow (40 mÅ) bandpasses centered on the Sodium D-lines, 80 mÅ\/ apart from the central wavelenght. A continuum broad-band channel is simultaneously available. The MOF stability and reference wavelenght permit to reach an high sensitivity in the power spectrum of the oscillations, despite the very low spectral-limited transmitted light. The most recent version of the instrument has characteristics of portability (60\times10\times10 cm \times 10 Kg, PMT not included), fast mounting and low cost. Preliminary results obtained during the impact of Comet SL-9 on Jupiter in 1994 and in 3 consecutive nights in 1996 are presented [1,2]. The importance of continuous observations for an unambigous detection and identification of the oscillation frequencies requires a network of at least 1m--class telescopes all around the world.
The authors thank the Ministero della Pubblica Istruzione and the Osservatorio Astronomico "V.Cerulli" di Teramo for financial support.
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{ \smallskip [1] Cacciani A., Moretti P. F., Dolci M., Brocato E., Smith E. J., 1995: Doppler Observations of the Impact of Comet P/Shoemaker-Levy/9, Fragment A, Geophys. Res. Lett., 22, 2437 \smallskip [2] Cacciani A., Moretti P. F., Dolci M., D'Alessio F., Giuliani C., Micolucci E., Di Cianno A., 1999: Search for global oscillations on Jupiter with a double-cell Sodium Magneto-Optical Filter, submitted to Astron. Astrophys.}
The author(s) of this abstract have provided an email address for comments about the abstract: alessandro.cacciani@roma1.infn.it