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fDesc[0] = "The software provides a view of Jupiter at four magnifications (actual Voyager images are used), along with a highly accurate ephemeris program that draws the four Galilean satellites in their proper positions relative to the planet at any time. Students make observations of Jupiter and its satellites at regular intervals over a period of several weeks and, by graphing the separation of each moon from Jupiter versus time, they measure the period and radius of each satellite's orbit.";

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