9400168 Michael F. A'Hearn Dr. A'Hearn and his colleagues plan to expand their normal observational program on comets and asteroids in order to carry out an extensive effort for Comet Shoemaker-Levy 9 and its impact onto Jupiter. They are emphasizing the study of the dust grains in the coma and tail, which together are a system much larger than the entire Jovian system. Observations will be conducted during the spring of 1994 to elucidate the properties of the grains. The investigators will then carry out a program of coronagraphic imaging and spectroscopy during the several weeks surrounding the period when the major fragments will impact the planet. This will be aimed at determining the interaction of the grains (and any gas) with the magnetosphere and ring and torus of Jupiter.