Skywatch Line for Wednesday and Thursday, September 20 and 21, 2023

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, September 20 and 21, written by Alan French.

The Sun rises at 6:40 A.M. on Wednesday and sets at 6:57 P.M. On Thursday it rises at 6:41 and sets at 6:55. This Thursday has just over 20 minutes less daylight than last Thursday.

The Moon is now approaching first quarter, which it will reach Friday afternoon. On Wednesday the Moon will be low toward the southwest at 8:00 P.M., only 11 degrees high and the visible face will be 31% in sunlight. Look for bright, reddish Antares, the brightest star in Scorpius, 5 degrees to the left of and slightly higher than the Moon. At 8:00 P.M Thursday night the Moon will be farther south, but still riding low in the sky, only 14 degrees above the horizon. It will be 41% in sunlight. Antares will be just over 8 degrees to the lower right of the Moon.

While the time around first quarter is a great time for exploring the Moon with a telescope, it is better to have it high in the sky. A low Moon, however, makes it easier to steady a pair of binoculars, perhaps resting your elbow or arms on a railing or fence, or even a car, when checking out the lunar landscape. (If you have binoculars and a camera tripod, see if the binoculars are threaded to fit on a tripod.) There is

quite a bit to see with 7 to 10 power binoculars, and the view changes from night to night. Right now, the Sun is rising on the Earth facing side of the Moon, bringing new details into view each night until full Moon. Why not explore the Moon a little with binoculars or telescope?

The Moon sets at 9:29 PM on Wednesday and 10:11 PM on Thursday.

Be sure to check out the northern to northwest horizon for aurora borealis or Northern Lights each clear night. A geomagnetic storm on Monday night, September 18, provided shows for people in northern U.S. states, including Minnesota, Wisconsin, Wyoming, and Montana. Our region can get good displays occasionally.