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Monday, April 12, 2010
Mars Approaches the Beehive Cluster (M44)
Click image to enlarge.
There's a glorious spectacle in the evening sky this week for observers with binoculars or small telescopes. Mars, shining brightly high in the west-southwest sky, glides past the Beehive (Præsepe) Cluster (M44), with closest approach on April 16th, just a little over a degree (the width of two full Moons) from the centre of the cluster. Even a few days before closest approach, it's a magnificent sight. Since clear skies are a rare commodity this time of year at Fourmilab, I took advantage of tonight's pellucid seeing to photograph Mars closing in upon the Beehive. Mars is the bright blob toward the right (overexposed and blown out in colour by an exposure long enough to capture the fainter stars). The Beehive, as an open cluster, lacks clearly defined boundaries—it kind of fizzles out until it blends into the background stars. It's difficult to determine the distance of objects such as this; the cluster is estimated to be somewhere between 520 and 610 light years from the solar system. Mars is, at the moment, about nine and a quarter light minutes from Fourmilab: in the foreground as photographers are wont to say. This photo was taken with a Leica M9 digital camera and Noctilux ASPH 50mm lens at f/0.95, with a four second exposure time and sensitivity of ISO 800. The camera was mounted on an unguided tripod, with the shutter tripped with a mechanical cable release. Hey, who said the Noctilux at full aperture doesn't have depth of field!Posted at April 12, 2010 00:24