Double Duty

One of the brightest stars of the summer sky is performing double duty here in the dead of winter — it appears in both early evening and early morning. And from far-northern latitudes, it never sets at all — it’s in the sky every hour of the day, all year ’round.

Deneb is at the tail of Cygnus, the swan. The brilliant star forms one point of the Summer Triangle, which soars high overhead during the summer months.

Deneb remains visible for all or most of the year, though, because it’s quite far north in the sky. It’s about 45 degrees from the North Star, Polaris. From the northern hemisphere, Polaris is always at the same point in the sky, day or night. Its altitude depends on your latitude. From 30 degrees north, it stands 30 degrees above the northern horizon. And from 50 degrees north, it’s 50 degrees above the horizon.

As Earth turns on its axis, any star that’s within that range of Polaris remains in view all night. From Seattle or Duluth, for example, that includes Deneb. At this time of year, the star passes just above the horizon during the night.

For skywatchers south of that range, though, Deneb does disappear — for anywhere from a few minutes to hours. From most of the United States, it’s in the northwest as night falls now and sets a few hours later. But it climbs into view again before dawn — this time in the northeast.

So keep watch for Deneb — a summer star that’s performing double duty on winter nights.
 

Script by Damond Benningfield