Sunday, January 14, 2001

Double Shadows on Jupiter Jan. 14th

A very nice view from Los Gatos! I had my 10" f/5.6 Dob driven on an Equatorial Platform. I finally took time to really align the platform dead-on.... figured out a brutish way of doing it... and the planet stayed centered in my 7mm eyepiece for tens of minutes at a time. Wonderful! The best views I had were at lower power, since the seeing was kind of soft, my 12mm Nagler did quite nicely until a bit of fogging threw a bright spot around the planet.

The moons were fun to watch. Io's shadow was small but distinct, sitting on the white line bisecting the southern equatorial belt precisely. While I was watching the shadow transiting, I suddenly saw Ganymede show up on the trailing limb, just beginning to pop out against the black of space. I also felt there was a bit of ruddy somewhat orange color to Io, but I don't know for sure. I went indoors for a short while, and came out later to find the platform still dead-on, and Ganymede's shadow encroaching into the leading limb. I watched for about 15 minutes, fighting a bit of softness and dew, but the view was really spectacular... seeing planetary motion in real-time... the much larger shadow of Ganymede making its way across ad Io's small shadow headed toward the limb.

This sort of event is fun!

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