Alas, I post this only as a teaser! Tonight (November 11, 2007) at 23:38 LMT (ADT) two of Jupiter’s Moons, Io and Europa, will pass across the face of the giant gas planet. Jupiter will have long set in the Western sky by the time the event happens but, if the planet were visible, we would not only see the moons crossing the face of the planet but also the shadows of each of the moons.
So, why post this if we can’t see it? ‘Cause I think these events are so awesomely cool! Shadow transits are quite common and fun to watch. You’ll need a telescope of at least 100 mm (4 inches) in aperture, a dark sky, and good seeing conditions to observe the event but after you’ve seen your first one, you’re hooked. Unfortunately, Jupiter will reach superior conjunction (on the other side of the sun from Earth) on December 23 so for the rest of this year the planet will either be to close to the sun (visually) for optimal viewing or will not be visible at all. The planet won’t return for optimal viewing until late spring, summer, and early fall of 2008. Even then, Jupiter will reach a max altitude above the Southern horizon of only slightly more than 20 degrees (as observed from mid northern latitudes).
But, if we could see this evenings event it would look something like the following video. The clip is about 2 minutes long with the first minute in real time and the second minute sped up 300 times. The entire event from Io’s shadow becoming visible to Io’s shadow disappearing takes slightly more than two hours in real time.
The video was created with Starry Night Digital Download 6 from Imaginova.
Filed under: Astro Facts
