McEwen, A., Geissler, P., Pappalardo, R., Milazzo, M., Porco, C., Belton, M., Johnson, T., Squyres, S., Thomas, P., Roatsch, T., Neukum, G., Veverka, J., Turtle, E., Simonelli, D., Schuster, P., and the Galileo SSI team (2001). "Cassini and Galileo Observations of Io and Satellite Eclipses." European Geophysical Society XXVI General Assembly PS6.01.


Cassini and Galileo imaging systems will observe the Galilean satellites in December 2000 and January 2001. Here we describe imaging plans for eclipse observations of Io, Europa, and Ganymede and sunlit observations of Io. During Ganymede and Europa eclipses we hope to see spatial and temporal variations in emissions from their atmospheres of neutral oxygen, which are excited by energetic electrons in Jupiter's magnetosphere. We will also image Europa through filters appropriate for sodium and sulfur dioxide emissions. During Io eclipses we will see the colorful emissions from sulfur dioxide, sodium, neutral oxygen, and perhaps other components of the atmosphere and active volcanic plumes, as well as high temperature silicate eruptions. We expect to see significant spatial and temporal variability on Io. Cassini will acquire sequences of images (movies) of 10 eclipses: two of Ganymede, two of Europa, and six of Io. Galileo will acquire close-up images of Ganymede in eclipse on Dec 28, and a series of 8 observations of the Io eclipse on Dec 31--providing stereo coverage with Cassini. Both spacecraft will also acquire multi-spectral imaging of Io's surface and plumes. We will present the initial results from these experiments.