[AZ-Observing] Cloudy Nights

Well, as was the case across most of the state, lingering afternoon clouds 
thwarted my marathon plans last night. M74, M110 and M77 all remained veiled 
behind thin cirrus and by 8:30 pm, I decided to put more focus on the "party" 
aspect of a star party.
About 20 folks from the Coconino Astronomical Society, Sirius Lookers of 
Sedona and Amateur Astronomers of Verde Valley had gathered at the Two Trees 
site 
between Sedona and Cottonwood. Most weren't there to marathon. Those of us who 
were, had abandoned the effort in favor of planetary observing after a couple 
of hours.

Jupiter and his entourage put on a nice display. It was about 9:15 pm when I 
turned my 10-inch to Jove and saw Ganymede's shadow north or the North 
Equatorial Belt (NEB) and just inside the following limb. Another smaller 
circular 
feature was visible along the central meridian north of the NEB.

Thus, ensued a vigorous debate among several of us about the more central 
object. Was it a satellite or a shadow? The fact that it did not appear jet 
black 
in color led me to conclude it was the satellite casting the shadow that had 
recently begun transiting the disk. Finally, somebody found the March issue of 
S&T and the debate was resolved: it was Ganymede.

In the interim, we saw Europa disappear behind the Jovian disk. At about 
10:15 pm, Io began a disk transit. This event was followed about 25 minutes 
later 
by Io's shadow ingress. And just a few minutes after that, Ganymede moved off 
the disk and against a dark night sky to confirm that the object of our 
earlier discussion was, indeed, a satellite.

All-in-all, we had a fine evening despite the early cloudiness.

Regards,

Bill Ferris
"Cosmic Voyage: The Online Resource for Amateur Astronomers"
URL: http://www.cosmic-voyage.net


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