The Galilean Triangle, 2004/2/16 UT

Although the transparency was far from ideal and the temperature was a
frigid 12 degrees Fahrenheit, I nevertheless enjoyed observing at the
ASH Naylor Observatory on Sunday night. The highlight was most
definitely the close grouping of Io, Europa, and Callisto.

After viewing M78 (I did not see McNeil 1, of course), M42 (six
components of the Trapezium were visible), M43, Saturn, NGC 2392, and
Beta Monocerotis with the 17" f/15 classical Cassegrain at
magnifications ranging from 162 to 259x I took a warm-up break. When I
returned to the French Dome I was joined by three fellow ASH members.
We searched for two of Saturn's more difficult satellites using
magnifications of 381 and 404x.

Around 3:30 UT I slewed the 17" to Jupiter. The GRS was just past the
CM and looked rather pale. Io, Europa, and Calliso formed a small
triangle to the east of the planet while Ganymede orbited far to the
west. With time the triangle flattened to a dogleg pattern.

One member stayed on with me. We had a look at M65, M66, Beta
Monocerotis (a first for him), M78, and M42.

I took another break, a much longer one, and eventually returned to
the dome to have another peek at Jupiter, going as high as 381x. I
noticed what looked to be a white oval adjoining the NEB and to the
west of the CM around 9:10 UT. By that time the Galilean triangle was
just a slightly crooked line.

I finished up the night with a quick perusal of M104.

Dave Mitsky


Dave Mitsky