In the Sky This Month

Venus is the brilliant “evening star,” low in the west at sunset. It outshines all the other planets and stars in the night sky. It’s especially prominent tonight because it stands close to the crescent Moon.

The word “planet” comes from a Greek word that means wanderer, because each of the planets moves against the background of “fixed” stars. Occasionally, though, a planet stands still against that background. Mercury and Saturn both reach such a standstill this month.

A pair of abandoned constellations sit on the back of Camelopardalis, the giraffe, which in the northern sky as night falls. One is the reindeer, while the other is the harvest keeper. Both were created to honor events of the 18th century.

The star 47 Ursae Majoris lies near the bowl of the Big Dipper. In a dark sky, it is barely visible to the unaided eye. It is home to a planet, which is too faint to see. Astronomers discovered the planet because its gravity tugs at the star.

The Orion Nebula is 1,500 light-years away, yet it’s easily visible to the eye alone. It contains thousands of newborn stars. But it shines so brightly thanks mainly to just one star, Theta-1 Orionis C-1. It’s a member of class “O,” the most impressive class of stars in the galaxy.

The hottest and brightest stars in the galaxy are also the rarest. Known as class “O,” they account for about one of every 10 million stars. Yet they are so dazzling that several of them are visible to the unaided eye.

A pair of lions stands high overhead in mid-evening. Only one of the lions, the constellation Leo, deserves its name. The other, Leo Minor, is a scrawny patch of stars that is difficult to find. It stands to the north of Leo.

NGC 2467, a nebula in the constellation Puppis, is well to the left of Sirius, the brightest star in the night sky, and is visible through binoculars. It’s actually several stellar nurseries that line up in the same direction.

A legendary boat sails low across the south: the Argo, which carried Jason and the Argonauts on the quest for the golden fleece. It’s been split apart to make three constellations: Puppis, the stern; Vela, the sail; and Carina, the keel.

Camelopardalis, which represents a camel with the spots of a leopard, stands above W-shaped Cassiopeia in the northern sky at nightfall. You need skies that are dark enough to see the Milky Way to pick out the stick figure outlined by the camel’s stars.