Skywatch Line for Wednesday and Thursday, October 25 and 26, 2023

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, October 25 and 26 written by Alan French.

The Sun rises at 7:20 A.M. on Wednesday and sets at 5:58 P.M. On Thursday it rises at 7:22 and sets at 5:56. This Thursday has  just over 19 minutes less daylight than last Thursday.

The Moon was at first quarter last Saturday and a waxing gibbous Moon now rises in the afternoon. On Wednesday afternoon the Moon will rise at 4:38 in the east, appearing 88% illuminated. Moonrise on Thursday is at 5:00 P.M. and the Moon will appear 95% full. The Moon will reach full, the Hunter’s Moon, next Saturday.

On Wednesday night the gibbous Moon will be due south, 42 degrees above the horizon, at 10:26 P.M. Thursday’s Moon be 49 degrees above the southern horizon at 11:16 P.M. Saturn will be 40 degrees to the west (right) of the Moon. Brighter Jupiter will be 31 degrees to the Moon’s east (left).

Saturn now transits – is due south – at 8:49 P.M. It will be 34 degrees above the horizon and at magnitude +0.7, the brightest object in the area. To the eye Saturn has a yellow tint. Its lovely rings are easily
seen in any telescope magnifying 50 or 60 times.

Jupiter is now in the southeast at 11:00 P.M. and well above the horizon, 49 degrees high. When viewed through a telescope, planets generally look best when they are high in the sky and we are viewing
through less atmosphere.

The four largest and brightest of Jupiter’s moons, Io, Europa, Ganymede, and Callisto are visible in almost any telescope, and can be spotted in steadily held binoculars when well away from the planet. The look like stars close to Jupiter.

At 11:00 P.M. on Wednesday night two moons, Ganymede and Callisto, will be well to Jupiter’s east, with Callisto farthest away. In a typical birding or spotting scope, which gives a view with the same orientation
as our eyes, the two moons will be to the lower left. An astronomical telescope may reverse or invert the view. The other two moons, Europa and Io, will be to the planet’s west, upper right in a birding scope.
Europa will be very close to Jupiter. (If you are confused about directions in your telescope, the two moons far from the planet and well separated from each other are Ganymede and Callisto to the east, the two close to the planet and closer together, are Europa and Io to the west.)

On Thursday night at 11:00 P.M. all four moons will be to Jupiter’s east. Io and Ganymede will be closest to the planet and close together. Ganymede will appear slightly brighter than Io. Next farthest east will
be Europa, with Callisto farthest from the planet.