The Big Dipper and Mizar
May 16, 2010
The photo above shows a nice view of the Big Dipper as captured above Ellington, Connecticut. This perhaps most recognizable asterism consists of the seven brightest stars in the constellation Ursa Major (Big Bear). It’s high in the northern sky during the month of May – said to be at upper culmination. Since it’s a circumpolar constellation, it’s visible to inhabitants in the Northern Hemisphere all year long. The two end stars in the Dipper’s bowl are referred to as pointer stars. They point to Polaris or the North Star in one direction (higher in the sky on this photo) and to the bright star Regulus in the opposite direction. Tracing the stars in the Dipper’s handle leads to the brilliant star Arcturus and then on to another first magnitude star, Spica. Notice the middle star in the Dipper’s handle, Mizar. If you have a good pair of peepers and the sky is dark, you’ll observe that it’s a double star.
Because it's considerably warmer now than a few months back, we're more inclined to inspect the night sky a little more carefully and not just take a casual glance before dashing inside to thaw our digits. One of the most conspicuous of all the constellations, Orion, has now departed the night sky. As if knowing that the fearsome hunter is out of sight, the two bruins (Ursa Major and Ursa Minor, the Big and Little Dipper) are a bit bolder this time of year and assuredly amble toward the zenith. If the weather is clear, step outside for a few minutes after it gets dark and look high to the north; the Dipper will be there for you. Photo taken on September 4, 2009 when the Dipper was at lower culmination.
Photo details: 20 second exposure; 28-80 mm lens; 28 mm focal length.