Archive for September, 2009

The Owl (maybe) Cluster

Wednesday, September 23rd, 2009
NGC 457

Few things in the night sky really look like what they’re named for. Queen Cassiopeia looks like a squashed “W”, and Andromeda looks like … well nothing really. Of course there are also exceptions like the Big Dipper. And then there’s NGC 457, an open cluter that looks like something – but nobody can agree on what.  It’s commonly called the Owl Cluster or the ET Cluster. One of my friends once said it looked like a koala, although I’d question his sobriety at the time. The “eyes” of the alleged koala are Phi Cassiopeiae, not actually part of the cluster. The cluster itself, made up of about 150 stars, can be imagined as a torso and appendages of some kind. This interesting little cluster is easy to find in Cassiopeia. Keep following the line formed by Epsilon and Delta Cassiopeiae until you reach a point almost even with Gamma Cassiopeiae. These lines aren’t exact, but they’ll get you in the area. And once you’re in the area, Phi Cassiopeiae should be easily visible through your finder scope. So go take a look at NGC 457, and decide for yourself what it looks like.

Finding the ... owl?

Twin Clusters, Twin Beauty

Thursday, September 10th, 2009
Twin clusters in Perseus

A densely packed open cluster can be a beautiful sight, glittering like an array of jewels in the sky.  But two of these clusters together is something truely remarkable.  In the constellation Perseus is such a double cluster, formed by NGC884 and NGC869.  This pairing is a favorite of many amatuer astronomers.  If you haven’t seen it, take a look.  It’s sure to become one of your favorites too.  The clusters are roughly 6800 and 7600 light years away, and have magnitudes of 5.3 and 6.1.  Although they are in Perseus, the easiest way to find the double cluster is to start with Cassiopeia.  Imagine a line between the two stars at the end of Cassiopeia.  From the midpoint of that line, imagine another perpendicular line.  That line will lead right to these cosmic jewels.  

Finding the Twin Clusters