The Changing of the Guard

While one season’s stars set, another season’s rise

If the melting snow — finally — weren’t enough to give the impression that winter was on the wane, then maybe the growing hours of daylight week to week will brighten you up. As we approach spring equinox March 20, our days grow noticeably longer, and the winter constellations appear to pick up speed as they exit, stage west.

The great winter constellation Orion shines high overhead in the south with sunset, but by midnight the great hunter is dipping beneath the west horizon. With the moon not rising until midnight and later this week, the hourglass figure of Orion stands out in stark relief against the black backdrop. Two brilliant stars stand out at either end of the hunter’s body: His western-most foot is marked by the blue star Rigel, seventh brightest in the heavens, while his shoulder is marked by the red-giant Betelgeuse, the 11th brightest star. You’re sure to recognize the three lined-up stars of Orion’s belt — Alnitak, Alnilam and Mintaka from east to west.

A sword dangles clearly from the belt, made up of several fairly bright stars and one that appears like a blur. Train a pair of binoculars or a telescope on this fuzz-ball and you’ll see that it is not a single star but hundreds, even thousands of stars. While the Orion Nebula is located some 1,500 light years away, at magnitude four it is the brightest nebula and the brightest deep-sky objects visible to the unaided eye.

Over the weekend, as Orion sets, look to the east for the moon in pre-dawn skies rising with Orion’s bane, the spring constellation, Scorpius. Luna rises just minutes past the witching hour separating Friday from Saturday, with Antares, the glaring red heart of the scorpion, just a few degrees behind. The following night — or morning — the moon rises after 1am, now trailing Antares by a mere three degrees.