Often you notice we refer to objects with an "M" number or Messier (think hockey) number. There are other designations such as NGC (New General Catalog) or IC (Index Catalog); all are simply catalogs or lists of objects that were located and mapped to celestial coordinates. They offer us a wealth of viewing pleasure and variety.
The Messier objects were cataloged in the 18th century by French astronomer Charles Messier. Messier's primary passion was the discovery of comets and he started his catalog to identify object that might easily be mistaken as comets. Many of the 110 objects on the list could never be mistaken for comets, so it is likely that the catalog eventually became a list of objects he prized simply for their own beauty. Pierre Mechain, Messier's colleague, discovered many of the objects and added them to the Messier list.
Most amateur astronomers expand their horizons past the moon and planets by working through the items in the Messier catalog. In this way they can view some of the most spectacular objects visible to us and they greatly improve their observing skills. The Messier catalog has a little of everything: galaxies, nebulae, globular clusters, open clusters and more. If you are in doubt what to look at on a particular evening, check out the M objects.
One last note on the Messier list. In March, it is possible to view all 110 objects in a single night. Known as the Messier Marathon, amateur astronomers start during the twilight hours of one of the nights around the new moon (no moon in the sky to hide the fainter objects) and rush to find all the objects before the sun rises the next morning. This is impossible if you are too far north and gets easier the farther south you travel. Okinawa is well positioned for a successful run. It does require a good strategy to approach the objects in the right order. The March 2002 issue of Astronomy magazine has a good guide to help plan your run.
For more information on the individual Messier objects, visit the Students for Exploration and Development of Space web site: http://seds.lpl.arizona.edu
Ryukyu Astronomy Club
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