January 2019 - Cosmic Pursuits

The complex of emission, reflection, and dark nebulae near the star Alnitak and Sigma Orionis. The Horsehead Nebula is at center. Sigma Orionis is the bright star to the left of the Horsehead. The pale white Flame Nebula, split in two by a dark lane of dust, is at bottom and just right of center. Image credit: Terry Hancock and GrandMesaObservatory.com

Perhaps the finest multiple star in the sky visible to both northern and southern observers, Sigma Orionis is a gravitationally-bound system of five stars, four of which are visible upon careful inspection with a small telescope. The brightest star of this group is one of the most luminous known, and it lights up the gas and dust around the famous Horsehead Nebula near Orion’s Belt. The star will one day expire, like many stars in Orion, in a spectacular supernova explosion.

Sigma Orionis doesn’t have an easy-to-remember name, but it’s not hard to find. It’s just south of Alnitak, the easternmost star in Orion’s Belt. The total visual magnitude is 3.6, so it’s visible even in light-polluted city skies [Read more…] about A Quintuple Star in the Constellation Orion

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An image of the Pleiades Star Cluster (Messier 45) and surrounding region. Image courtesy of Terry Hancock and Grand Mesa Observatory.

Like many observers both casual and serious, I do not tire of gazing upon the little star cluster known as the Pleiades. I’ve seen the cluster a thousand times, but I’ll still stop and take a long look at it without optics while out for a walk on a winter’s night. Some night I’ll grab a pair of binoculars and make a closer inspection of the cluster, which fits perfectly in the field of view of such an instrument. And if it’s not too cold, I’ll pull out a telescope and a wide-field eyepiece and spend 20 minutes taking in the astonishing view of this group of blue-white stars that formed while dinosaurs still roamed the Earth. Which, in celestial terms, was not all that long ago.

Why keep looking at the Pleiades after so many years? The cluster doesn’t appear to change, of course, in the restricted timescale of a human life. But the Pleiades is a profoundly beautiful sight, as pleasing as a field of alpine wildflowers, and I never fail to see new patterns of stars both bright and dim that I hadn’t noticed before [Read more…] about The ‘Seven (Dusty) Sisters’

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