NGC 225 & Stock 24 -- Open Clusters in Cassiopeia
Two Very Different Cassiopeia Open Clusters
The Sailboat or Broken Heart Cluster (NGC 225) is listed as Stephen O’Meara’s “Hidden
Treasure 2”. The Sailboat sits just outside of the edge of the glittering Milky Way as it passes
through the Constellation Cassiopeia. The Sailboat is easily visible in binoculars. It is large (15
arcminutes) and with few stars (75 according to best estimates). It gets its name because it
appears to be divided into two sections, giving the appearance, to many observers, as either a
boat with sail or a broken heart. Sadly, I am not sure I can make out either the sailboat or the
broken heart without a great stretch of imagination. There are no dim background stars in the
cluster when viewed through the telescope. The Open Cluster, Stock 24, is very different and I
cannot find it using just binoculars. It is 3x as far away as the Sailboat Cluster, 3x smaller in
appearance, but has over 2 ½ times as many stars. Within the cluster proper most of the stars
are below the resolution of my telescope and thus their combined starlight makes the cluster
appear as a soft glow. Stock 24 is embedded within the spiral arm of the Milky Way and thus is
surrounded by many more neighboring stars than the Sailboat Cluster. In the eyepiece, both
clusters fit within the same field-of-view, where they are separated by ¼ the distance of a full
moon. Each is worthy of its own study. Together, they provide a delightful contrast.
Treasure 2”. The Sailboat sits just outside of the edge of the glittering Milky Way as it passes
through the Constellation Cassiopeia. The Sailboat is easily visible in binoculars. It is large (15
arcminutes) and with few stars (75 according to best estimates). It gets its name because it
appears to be divided into two sections, giving the appearance, to many observers, as either a
boat with sail or a broken heart. Sadly, I am not sure I can make out either the sailboat or the
broken heart without a great stretch of imagination. There are no dim background stars in the
cluster when viewed through the telescope. The Open Cluster, Stock 24, is very different and I
cannot find it using just binoculars. It is 3x as far away as the Sailboat Cluster, 3x smaller in
appearance, but has over 2 ½ times as many stars. Within the cluster proper most of the stars
are below the resolution of my telescope and thus their combined starlight makes the cluster
appear as a soft glow. Stock 24 is embedded within the spiral arm of the Milky Way and thus is
surrounded by many more neighboring stars than the Sailboat Cluster. In the eyepiece, both
clusters fit within the same field-of-view, where they are separated by ¼ the distance of a full
moon. Each is worthy of its own study. Together, they provide a delightful contrast.