In the Sky This Month

Camelopardalis, the giraffe, is one of the largest constellations, covering a big wedge of the northern sky. But it isn’t very bold. All of its stars are so faint that you need to get away from city lights to see them.

The Moon and two bright planets form a beautiful triangle at dawn tomorrow. Brilliant Jupiter stands to the right of the Moon, with fainter orange Mars close below them.

Venus will pass behind the Sun today, so it is lost from view in the Sun’s glare. It will return to view next month, when it will shine as the brilliant Evening Star.

The Moon is at last quarter today at 4:25 p.m. CST. Sunlight will illuminate half of the lunar hemisphere that faces Earth. The illuminated fraction will continue growing smaller until the Moon is new, on January 16.

Taurus, the bull, passes high overhead this evening. Its brightest stars form a long, thin wedge, with its brightest star, orange Aldebaran, at its southeastern corner. Taurus is at its highest around 9 p.m.

Orion is in the eastern sky at nightfall. Its three-star belt points straight up from the horizon, with Orion’s other bright stars arrayed to its left and right. From top to bottom, the stars of the belt are Mintaka, Alnilam, and Alnitak.

The planets Mars and Jupiter are in the east at first light right now. Jupiter is the brightest point of light in the sky at that hour, with fainter Mars close to the right of Jupiter tomorrow and below Jupiter the next day.

The Moon will will pass close to Regulus, the star that marks the heart of Leo, the celestial lion, tonight. And for skywatchers from Alaska and other high northern latitudes, the Moon briefly will pass in front of the star, blocking its light.

The Big Dipper hunches low in the north at nightfall, with its bowl not far above the horizon. It rotates across the sky during the night, reaching its highest point early in the morning. It is still high in the sky as night gives way to twilight.

Cassiopeia the queen, whose brightest stars form a letter M, stands high in the north at nightfall. One of its most interesting denizens is Cassiopeia A, the remnant of an exploded star. It’s the brightest source of radio waves outside the solar system.