As we pass through the orbital plane of Jupiters moons, there are plenty of mutual events, both occultations and eclipses. The deepest and most favorable of these events occurred this morning, when Callistos shadow covered more than 80 percent of Ganymede. The geometry was such that the distance between Callisto and Ganymede was 1.6 million miles at the time of the eclipse. Seeing was very unsteady this morning, but I gave it a shot with the webcam this morning. I used a 15-inch with a 2x Barlow lens, and further doubled the scale in the post-processing. This time-lapse series runs 19 minutes, and used a 1-minute interval between the finished frames. The shadow passed north of (above) center, which is evident in the sequence. Ganymede is held stationary on the right to show it being eclipsed, Callisto is at far left, with Europa near Callisto. Id complain more about the seeing conditions in Arizona on this January night, but it could be worse; I could be in Buffalo. pbase/polakis/image/158918439/original
Posted on: Sat, 24 Jan 2015 01:43:44 +0000