In the Sky This Month

NGC 6505 is a spiral galaxy enwrapped in the coils of Draco, the dragon. The galaxy is more than a third of the way up the northwestern sky at nightfall and is visible through a small telescope.

The planet Jupiter rises above the Moon this evening. The planet looks like a brilliant star, outshined only by the Moon and Venus. Binoculars will reveal Jupiter’s four largest moons, which look like small stars.

The Moon stands near the planet Jupiter and the twins of Gemini tonight. Jupiter looks like a brilliant star below the Moon as they climb into view. Castor, the fainter of the twins, is to the left of the Moon, with Pollux, the brighter twin, to the lower left.

Vega, one of the night sky’s brightest stars, is disappearing from evening view this month. Tonight, it sets at about 9:30 or 10 p.m., but by month’s end it will set by about 8:30. Look for it in the northwest.

Elnath, the second-brightest star of Taurus, is close to the lower left of the Moon this evening. The Moon will move toward the star during the night, and they will be closest at dawn. The gap will be smallest for skywatchers on the West Coast.

Eridanus, the river, meanders across the southern sky at this time of year. It is one of the largest constellations, stretching almost 60 degrees. Its northern end is northwest of Rigel, the brightest star in Orion.

The year’s earliest sunsets come over the next couple of weeks, even though the shortest day of the year isn’t until December 21, the winter solstice. The date of earliest sunset happens first at southern latitudes, then works northward.

Hamal, the brightest star of Aries, the ram, is in the east at nightfall, well to the left of the Moon. Hamal is at the end of its life, so it has puffed up to giant proportions. That change may doom the only planet known to orbit the star.

All three “minor” constellations are in good view at dawn: Ursa Minor, Canis Minor, and Leo Minor. Ursa Minor, the little bear, is the most famous. Seven of its stars form the Little Dipper, which is in the north, directly below the Big Dipper.

The shortest season on the planet Mars begins today: autumn in the northern hemisphere and spring in the south. It will last for 142 Mars days, which is almost eight weeks less than the longest season. Mars will return to view, in the dawn sky, in the spring.