Skywatch Line for Wednesday and Thursday, July 30 and 31, 2025, written by Alan French

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, July 30 and 31, 2025, written by Alan French.

The Sun rises at 5:45 A.M. on Wednesday and sets at 8:18 P.M. On Thursday it rises at 5:46 A.M. and sets at 8:17 P.M. Thursday lost just under 14 ½ minutes of daylight compared to last Thursday. By the end of the month, we will have lost just over 46 ½ minutes of daylight since June.

The Moon was new last Thursday afternoon and is now headed toward first quarter, with a fat crescent waxing Moon in the evening sky. On Wednesday at 8:30 P.M. a 36% sunlit Moon will be 22 degrees above the southwestern horizon. It will set at 10:56 P.M. At 8:30 P.M. Thursday the Moon will be farther east, 45% in unlight, and 23 degrees high, setting at 11:16 P.M. The Moon will reach first quarter Friday morning. The Moon was in Virgo on both nights, indeed it will have spent about 3 ¾ days in Virgo, the second largest constellation, when it moves into Libra.

The Southern Delta Aquariid meteor peaks on Wednesday morning, July 30, best seen from moonset at 10:37 P.M. Tuesday night, through dawn on Wednesday. Meteor showers are best after midnight, which is 1 A.M. EDT now, when we are on the front of the Earth as it moves through space. The ideal time to watch for meteors will be from 1 A.M. Wednesday through the beginning of nautical dawn at 4:33 A.M., although darker sites may see some interference from twilight just before 4:00. From dark skies you might see a dozen meteors per hour. Our northernly latitude is hampered because the radiant, the point the meteor’s trails

point back to, is low in the sky. Locations in the southern U.S. might see twice as many.

At 3 A.M. the radiant is 31 degrees above the southern horizon. The horizon and reduced transparency near it will cut off meteors appearing well south of the radiant. Our best view will be of meteors appearing above the radiant. There are also some minor showers now that may add to the display. The Southern Delta Aquarids will remain active, producing at least half its peak numbers, through Saturday morning.

Whether you are up to watch for meteors in the morning, or simply up before sunrise, look for brilliant Venus toward the east northeast. Venus rises at 2:48 A.M. on Wednesday morning. By 3:45, just before the first hints of astronomical dawn, it will be 9 degrees high, shining at magnitude -4.0 against dark skies. The situation will be essentially the same on Thursday and Friday mornings, although Venus is slowly moving lower each day. By 5:00 A.M. you will have a nice view of Jupiter, 10 ½ degrees to the lower left of Venus, with Castor and Pollux 13 degrees to

the left of Jupiter.