Skywatch Line for Monday and Tuesday, September 29 and 30, 2025, written by Alan French

This is Dudley Observatory’s Skywatch Line for Monday and Tuesday, September 29 and 30, 2025, written by Alan French.

The Sun rises at 6:51 A.M. on Monday and sets at 6:40 P.M. On Tuesday it rises at 6:52 A.M. and sets at 6:38 P.M.

The Moon reaches first quarter early Monday evening, having complete one-quarter of its trip around Earth since new Moon on the afternoon of Sunday, September 21. At 7:30 P.M. on Monday the Moon will a little west of due south and 17 ½ degrees above the horizon. On Tuesday and 7:30 P.M. it will be south and 20 degrees high. Astronomers like to view celestial objects when they are high in the sky and looking through less atmosphere, but the low altitude of the Moon now makes it easier to view through binoculars. When steadily held or supported binoculars can give a nice view of the Moon, revealing a lot of detail invisible by eye alone.

The Moon lies east of Sagittarius, The Archer. The brighter stars of Sagittarius form a well known asterism know as The Teapot. The teapot’s handle is just west of the Moon at 7:30 Wednesday evening and the spot is farther toward the west.

There is a nice pass of the ISS (International Space Station) over our area early Tuesday night. Look for the ISS coming up from the west northwestern horizon at 7:15 P.M. It will begin passing through the constellation Boötes, well above its brightest star, Arcturus, just before 7:17. It will then pass above Corona Borealis and then through Hercules.

By 7:18 the space station will be passing below bright Vega and then through Aquila the Eagle. After passing through Aquila, it will be head down toward the northeastern horizon and it will disappear before 7:22.

At its brightest it will reach magnitude -3.5.