In the Sky This Month

The constellation Hercules rises in early evening and stands clear of the northeastern horizon a couple of hours after sunset. The constellation is defined by a lopsided square of stars known as the Keystone.

The most amazing object visible through a small telescope looks like a star, yet it packs the power of 10 trillion Suns. 3C 273 is a quasar-a disk of superheated gas around a monster black hole. It’s in Virgo, a third of the way up in the southeast at nightfall.

The Lyrid meteor shower should reach its peak tomorrow night. Under a dark sky, you might see up to a couple of dozen meteors per hour between midnight and dawn. Unfortunately, the Moon will be in the sky then, so its light will compete with the fainter meteors.

Messier 3 is a cluster of about 500,000 ancient stars. It’s 34,000 light-years away, in Canes Venatici, the hunting dogs. The cluster isn’t bright enough to see with the eye alone, but is an easy target for binoculars.

Orion is sinking from view. The constellation is low in the west as darkness falls. Its most conspicuous feature is a short line of three bright stars, known as Orion’s Belt. The belt is parallel to the horizon, and sets in late evening.

V1309 Scorpii consists of two stars that merged to form a single star, producing a brilliant outburst called a red nova. Tomorrow, the star is just a tick to the lower left of the Moon at dawn. But it’s so far away that it’s too faint to see without a telescope.

W Ursae Majoris consists of two stars that are touching one another. The system is in the great bear, which includes the Big Dipper. W Ursae Majoris is well to the upper left of the dipper’s bowl at nightfall, and is visible through binoculars.

Antares, the heart of the scorpion, stands close to the left or upper left of the Moon at dawn tomorrow. It’s a system of two stars, but only one is visible to the eye alone. If it took the Sun’s place it would swallow the four inner planets, including Earth.

HD 162826 is a star that could have been born in the same cluster that gave birth to the Sun. It rises above Vega, the brightest star of Lyra, in the northeast in late evening. But you need binoculars to see this possible solar sibling.

Orion is in the west and southwest at nightfall. Look for its three-star belt, parallel to the horizon. The hunter’s brightest stars, Betelgeuse and Rigel, stand above and below the belt. Its next-brightest star is Bellatrix, to the upper right of the belt.