Skywatch Line for Wednesday and Thursday, July 31, and August 1, 2024, written by Alan French

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, July 31, and August 1, 2024, written by Alan French.

The Sun rises at 5:46 A.M. on Wednesday and sets at 8:16 P.M. On Thursday it rises at 5:47 and sets at 8:15. This Thursday has 14 minutes 47 seconds less daylight than last Thursday. We lose 46 minutes, 54 seconds of daylight in July.

Forecasters say there is a chance for aurora on Tuesday night into Wednesday morning, so, if the skies cooperate, keep an eye on the sky after dark. Free of interference from moonlight, this would be a fortuitous time for a display of northern lights. While modest displays are often confined to the north to northwestern skies, active displays can appear anywhere in the sky.

The Moon was at last quarter last Saturday and is now headed toward new. A waning crescent Moon now rises in the morning hours and the evening skies are moonless and dark.

The Moon rises at 1:19 A.M. Wednesday morning and is in the east at 4:30 A.M., appearing 17% sunlit. It is close to Jupiter and Mars, with bright Jupiter 8 degrees to its upper right, shining at magnitude -2.1. Reddish Mars is 7 degrees above and right of Jupiter and at magnitude +0.9. The Moon sets at 6:06 P.M.

The Moon rises at 31, 2:22 A.M. on Thursday morning and is in the east northeast, 19 degrees high, at 4:30 A.M., when it will appear just under 10% sunlit. Its eastward motion among the stars since Wednesday will have moved it farther from Jupiter and Mars. Jupiter will be 20 degrees from the Moon. Mars will be 6 ½ degrees to the upper right of Jupiter. The Moon will set at 6:58 P.M.

Early risers on Friday morning can catch a slender old Moon. At 4:30 A.M. it will be 9 degrees above the east northeast horizon and only a little over 4% of its visible face will be in sunlight. The Moon reaches new on Sunday.

There is a nice high pass of Tiangong, the Chinese space station, over our area on Wednesday night. Look for Tiangong coming up from the western horizon at 9:14 P.M. It will be headed roughly toward Arcturus, the brightest star in Boötes. Arcturus is 49 degrees above the west southwestern horizon. Just after 9:16 Tiangong will be passing south of Arcturus. The space station will then pass south of Corona Borealis, through southern Hercules, and well south of Vega. Just before 9:19 it will pass north of Altair, in Aquila, the Eagle. Shortly after 9:19 it will move into the Earth’s shadow and fade from view low toward the east. At its brightest it will reach magnitude -2.1.