Monday, March 14, 2016

brief jupiter double shadow

This evening from about 7:30pm to 9:30pm there was to be a double shadow transit of Jupiter, Io and Europa.  I opened up the shed upon arriving home from work, and went out after eating dinner at 7:30.  It was still twilight so I collimated and pointed to Sirius to get the finders aligned -- and wouldn't you know the Pup, Sirius B, was easily visible.  The seeing was not particularly good, and the transparency was awful.  I suspect because it was still twilight out Sirius itself did not shine so "brightly" so the Pup was outside the usual diffraction mess.  I tried this trick with Antares last year, trying to see its B star in the twilight, but no such luck that time. 

Jupiter was too low and I needed to run an errand.  I came back at around 8:40pm and Jupiter still had not cleared the neighbor's roof from where the 12.5-inch stood.  And there were clouds moving in from the west, fast.  I dashed to set-up the 8-inch, and was just able to catch the event.  I saw the two shadows at 180x nearly on top of each other; one (Io's) was obviously larger than the other.  I had Val take a look; it took a couple of minutes but she saw it too.  When I looked again the shadows had merged, it appeared -- but the view was very soft so it could have been tube currents or the high clouds ruining the view.  Coming outside a little while later, the sky was lost to cloud.

It will be clear for the next couple of days, so hoping for more viewing soon.

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