Skywatch Line for Friday, July 28, through Sunday, July 30, 2023

This is Dudley Observatory’s Skywatch Line for Friday, July 28, through Sunday, July 30, written by Sam Salem.

On Friday, Sun rises at 5:42am and sets at 8:21pm; Moon sets at 12:57am and rises at 4:55pm.

On Friday, the Moon shines just a few degrees left of Antares, the brightest in the zodiacal constellation of Scorpius, through the evening.

On Saturday, the Moon hangs just off the spout of the Sagittarius Teapot in the evening. Use binoculars to help you pick out the Teapot stars through the moonlight. The Teapot is about twice as wide as a typical binocular’s field of view, so expect to sweep around a bit to get it all. On Sunday, the Moon is on the other edge of the Teapot, in its handle.

Jupiter, at magnitude –2.4 in the constellation of Aries, rises around 1 a.m. in the east-northeast. By the beginning of dawn, it shines very high toward the southeast.

Saturn, at magnitude +0.7 in dim Aquarius, rises in late twilight. It’s highest in the south, and sharpest and steadiest in a telescope, before the first glimmers of dawn.

Uranus, at magnitude 5.8 in Aries, is high in the east by the beginning of dawn. It’s about 10° lower left of Jupiter.

Neptune, at magnitude 7.9 at the Aquarius-Pisces border, rises after dark and is high in the south-southeast before dawn begins, about 20° east of Saturn.

The zodiacal constellation Scorpius the Scorpion is one of the few constellations that looks like its name. That’s because it’s a noticeable, J-shaped pattern of stars resembling a real scorpion’s curved tail. The tail of Scorpius is low due south after dark, to the lower right of the Sagittarius Teapot. Look for the two stars especially close together in the tail. These are Shaula, or Lambda, and fainter Lesath, or Upsilon Scorpii, known as the Cat’s Eyes. They are also seen as the Scorpion’s stinger. the stars are 0.6° apart and tilted at an angle. Both stars are blue-white giants. The fainter one is the nearer one. Shaula, is a triple star system and shines at 1.62 magnitude. Lesath, the fainter star of the Stinger pair, doesn’t have any known companions. It shines at 2.7 magnitude. The best time to see Scorpius and its Stinger stars in the evening sky is during the summer and early autumn. Shaula is the second brightest star in the constellation Scorpius, after Antares. Shaula is also the 24th brightest star in the sky.

Between the Cat’s Eyes and the Teapot’s spout are the open star clusters M6 and M7. A line through the Cat’s Eyes points right by nearly a fist-width toward Mu Scorpii, a much tighter pair known as the Little Cat’s Eyes. They’re oriented almost the same way as Lambda and Upsilon. Use binoculars to resolve the Mu pair and explore the M6 and M7 open star clusters.