Deep Sky Feature for November

deep sky object2



Picture saved with settings embedded. ABOUT THE OWL CLUSTER

Amateur astronomers have their favorite little celestial gems that they like to show off to folks in their telescopes. We generally have a few for each season and one of my personal fall favorites (and one that many of my fellow amateur astronomers often overlook) is the Owl Cluster.

The Owl Cluster is an open cluster of stars located some 8,000 light years away. Stars are born in clusters and open clusters are just a loose assemblage of stars that all formed at about the same time, in the case of the Owl Cluster that was some 21,000 years ago (spring chickens…er, owlets by galactic standards).

The NGC designation means that the cluster is part of the New General Catalog which was created in the 1880’s and based in large part upon the observations of famed English astronomer William Herschel, his sister Caroline, and his son John. William first discovered the cluster in 1787.

The Owl Cluster gets its name for the fact that it does indeed look like an owl with outstretched wings. Whenever I show this cluster to folks with my telescope I rarely even have to give them pointers as to what to look for, they are almost immediately able to see the shape of an owl. owl clusterBut not everyone sees a predatory night bird when looking at it. Ever since the 1980’s people sometimes say that they see ET: The Extraterrestrial in this cluster. And, yeah, I can easily see how their imaginations will lead them to seeing the loveable little alien here (thanks, Stephen Spielberg!).

While binoculars will help you first locate the cluster it is an object that really comes into its own under low power viewing with a small telescope. Even apertures as small as two or three inches will reveal the owl (or, ET) shape.

About a dozen stars or so make up the body of the owl while two arcs of about a half dozen stars each make up the wings. But the real attention grabber are those two stars that appear close together and that form the eyes of the owl.   Bear in mind that these two bright stars are not actually a part of the cluster, they just happen to be two bright foreground stars that add a little extra magic to the view. The brightest of the pair is known as Phi Cas while the seemingly smaller, and dimmer star of the pair is HD 7902.


To find the Owl Cluster you must first locate the constellation of Cassiopeia. Owl Cluster in CassCassiopeia, the vain queen of Greek mythology, is a distinctive constellation made up of 5 rather bright stars that look like the letter ‘W’ turned upon its side. During the fall look for Cassiopeia in the northeastern sky at around 8:00 PM.

After you have found the queen sitting upon her celestial throne, look for the star Ruchbah. The name of this star is a shortened version of an Arabic phrase that refers to Cassiopeia’s knee. Just a little to the right of Ruchbah you will find the Owl Cluster. Use a pair of binoculars for your initial view and then switch to a telescope view using a low power eyepiece (24mm or 25mm will do nicely).




Posted in: Night Sky

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