This popular open star cluster, nicknamed the Pleiades and the Seven Sisters, is located only 400 light years away in the constellation of Taurus at a declination of +24 degrees. One of the brightest and closest open clusters in the sky, the Pleiades contains over 3000 stars. It spans 1.2 degrees in our apparent view, which corresponds to an actual width of about 10 light years.

This is the most famous star cluster in the sky, easily visible with the naked eye and the brightest object in the entire Messier Catalog. Many people, including myself for many years, mistakenly refer to this cluster as the Little Dipper. The real Little Dipper originates at the North Star, is barely visible, and is much bigger in size. This cluster looks sort of like a tiny dipper with a very short handle.

The nickname of this cluster is the Seven Sisters, even though only six bright stars are easily visible to the naked eye (in the darkest skies, some people can see as many as 14!). The Japanese name for this cluster is Subaru, which explains why the Pleiades star pattern is the basis for the Subaru car logo.  The Bible makes 3 references to Pleaides – in Amos 5:8, Job 9:7-9, and Job 38:31-33.

The Pleiades has always been a favorite object of mine, dating back to my early visual observing times. Even now, I see how many Pleiades stars I can see with my naked eye, even though it seems I am seeing less as I get older.  M45 is a challenge to image because of the way that the bright stars play havoc with the delicate nebulosity that is the most interesting feature of the object.   I am fascinated by all of the different nebulosity shapes - straight lines, long curving arcs, billowing clouds, shimmering sheets, and areas of fantastic chaos. 

I initially assumed that the nebula is a remainder of the original star cluster formation.  But based on velocity measurements, scientists believe that the reflection nebula is part of a molecular cloud that is unrelated to the star cluster.  The cluster and cloud are simply crossing paths.