An open star cluster is a group of stars all having the same origin, comprised of dozens to hundreds of young, hot stars mutually bound by gravitation. The gravitation forces within an open cluster are generally less than that of a globular cluster, so that over time the stars of an open cluster will eventually drift apart due to gravitational encounters with other clusters and clouds of gas as they orbit the Milky Way galactic center. There have been more than 1000 open clusters identified in our Milky Way galaxy.
The poster shows my 25 favorite open clusters out of the 125 that I have imaged to date. I had a tough time narrowing my list from 125 down to 25. I believe that many of the perceptions I have gained on the “best” open clusters over the years have been colored by their view at my eyepiece, as well as their reputations in books and magazines over the past 100 years. I tried to take a fresh look at these open clusters, judging them solely on their photographic merit.
Several traditional “best” clusters did not make the poster, including:
- M44 (Beehive)
- M6 (Butterfly Cluster)
- Melotte 25 (Hyades)
- M36 (Pinwheel Cluster)
Each of top 25 have nice variations in color and brightness, which appeals to my eye when looking at open lusters. Many are also associated with nearby nebulosity and dust.
Each of the clusters of the poster has previously been uploaded and described individually on Astrobin. They all reside in my
Astrobin Open Cluster Collection.
The technical data for these open clusters is shown in Revision B.
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