With the Jupiter system approaching vernal equinox on June 22, eclipses of the Sun on Io by the other satellites in the Jupiter system and other mutual events (such as occultations, when one satellite passes in front of another from Earth's perspective) have been occurring for the last few months. Tonight, the first total eclipse of the Sun by Ganymede this mutual event season will take place. A partial eclipse by Ganymede also occurred just 30 minutes ago (another partial eclipse occurred on June 1 as well). Below are two animations created in Celestia showing these two eclipses. For more information, check out my blog post from December about the mutual event season as well as my 365 Days of Astronomy podcast from last month.
Computer Animation of a partial eclipse of the Sun by Jupiter's moon Ganymede over the north polar region of Io on June 8, 2009. First half shows a view from 7,317 km above Io's northern leading hemisphere. Second half zooms in on the sun from near Io's north pole showing the partial eclipse. The animation runs from 20:38 to 21:08 UTC on June 8, 2009.
Computer Animation of a total eclipse of the Sun by Jupiter's moon Ganymede over the north polar region of Io on June 9, 2009. First half shows a view from 7,317 km above Io's northern anti-jovian hemisphere. Second half zooms in on the sun from near the eastern end of Lei-Kung Fluctus showing the total eclipse. The animation runs from 09:30 to 10:15 UTC on June 9, 2009.
These eclipses by Ganymede will occur every 8 days between now and mid-August with the most spectacular Ganymede eclipse occurring on July 15 when most of the trailing hemisphere of Io will be in the shadow of Ganymede.