Skywatch Line for Friday, December 29, through Sunday, December 31, 2023

This is Dudley Observatory’s Skywatch Line for Friday, December 29, through Sunday, December 31, written by Sam Salem.

On Friday, Sun rises at 7:25am and sets at 4:29pm; Moon sets at 9:41am and rises at 7:00pm.

For the second time this month, the moon will slide by the Beehive star cluster. This time it will be a waning gibbous Moon on Friday Morning. You will need binoculars to spot the dozens of stars in the busy Beehive star cluster. Also nearby will be the twin stars, Castor and Pollux, in the constellation Gemini.

On the mornings of Saturday and Sunday, the waning gibbous Moon will float near Regulus, marking the bottom of the backward question mark asterism called the Sickle. Regulus is the brightest star in the constellation of Leo the Lion. The Moon will lie close to Regulus on the final morning of 2023. They’ll rise late in the evening the night before and be high in the morning sky.

Mercury emerges into dawn view starting this weekend. Look for it about three fists at arm’s length lower left of Venus. Mercury is still only a difficult magnitude +1.3, but it’s brightening and climbing daily.

Venus, at magnitude –4.0 in the constellation of Libra, shines as the bright “Morning Star” in the southeast before and during dawn. It’s less high every week now. Closing in toward it from below is sparkly orange Antares, at magnitude +1.0.

Jupiter, at magnitude –2.6 in the constellation of Aries, is the bright white dot dominating the high southeast to south these evenings. It stands at its highest around 7pm. It has shrunk a little since opposition, but it’s still a good 45 arcseconds wide in a telescope.

Saturn, at magnitude +0.9 in the constellation of Aquarius, is getting lower in the southwest just after dark. Similarly bright star, Fomalhaut, in the constellation of Piscis Austrinus, the southern Fish, sits nearly two fists to Saturn’s lower left. Saturn sets around 9 p.m.

Sirius is highest in the sky at midnight during every turn of the year. Astronomers call this a midnight culmination of Sirius. As the New Year rings in, Sirius is at its highest point in the sky. Sirius, the brightest star in the sky, or the Dog Star, is part of the constellation Canis Major the Greater Dog. Sirius might also be called the New Year’s star. It’ll ring in 2024 by reaching its highest point in the sky around the stroke of midnight. Scan the dark sky and look for the prominent Belt stars of the constellation Orion the Hunter. Orion’s Belt always points to Sirius, you can identify Sirius easily. Sirius is the bottom star of the bright, equilateral Winter Triangle. The others are Betelgeuse in Orion’s shoulder to Sirius’s upper right, and Procyon the same distance to Sirius’s upper left. The Triangle now stands upright on Sirius, just about in balance.

On Saturday, the brightest asteroid in the sky, 4 Vesta, is just past opposition and creeping toward Zeta Tauri, the dimmer horntip of Taurus near the top of Orion’s club. Binoculars will show Vesta easily at magnitude 6.5. But you’ll need a fine-scale finder chart to tell it from all the other faint pinpoints in the area. Vesta will pass 0.2° from Zeta Tau on the nights of January 7th and 8th. Then it will cruise about ½° south of the dim Crab Nebula, M1, on January 11th, 12th, and 13th.