One of the most prominent constellations of summer skies transforms itself when the weather turns cold. It’s still the same pattern of stars, but because of the different viewing angle, it’s often seen as a different picture.
The constellation is Cygnus, the swan. During the summer months, it soars high across the evening sky, when more people are paying attention to the stars. Its brightest stars form a pattern that reminds many of a graceful bird, with a long neck and widespread wings.
By this time of year, though, Cygnus is in the western sky during the evening hours. Its beak points downward, with its wings roughly parallel to the horizon, as though it’s plunging toward the ground. Seen at this angle, it more closely resembles the constellation’s nickname — the Northern Cross.
The star at the top of the cross represents the tail of the swan — blue-white Deneb. It’s one of the biggest, brightest, hottest stars in our region of the galaxy. Although there’s some wiggle room in the distance, it’s probably close to 1,500 light-years away. That means the light we see from Deneb tonight has been crossing the Milky Way galaxy for a millennium and a half — a long-distance trek from a star that anchors two star patterns.
Look for Cygnus — the Northern Cross — standing well up in the west as night falls, and perching directly atop the horizon in mid-evening.
Tomorrow: bright lights for Christmas Eve night.
Script by Damond Benningfield, Copyright 2012
For more skywatching tips, astronomy news, and much more, read StarDate magazine.