What's New: March 2020

The Messier Marathon

The arrival of spring in the Northern Hemisphere can mean different things to different people. For many runners who travel from all over the world to Boston on the third Monday of April, for instance, it means participating in the Boston Marathon. But most of us lack the speed and the stamina required to compete in a race that long and grueling. For those such as us, there are other challenges we can consider. There is, for instance, the Messier Marathon.

Messier what?

Charles Messier (1730 – 1817 AD) was an astronomer with a predilection for hunting comets. Since a new comet can appear anywhere in the sky, large portions of the celestial sphere needed to be searched. Furthermore, a comet does not typically display distinctive features – such as a tail – until it nears the Sun; at that point, its gas, volatiles, and dust become heated and start to vaporize, making it appear larger and more prominent – and perhaps even developing a tail. Prior to that, it may appear as nothing more than a faint "fuzz ball," and it may be days before it displays movement as seen against the background stars.

The trouble is – as Messier found – is that there are a good number of objects scattered throughout the sky that appear as faint fuzz balls, and yet are NOT comets. In an effort to eliminate such distractions and false alarms, Messier decided to make a list of all the objects he came across that weren’t comets. Over time, the list compiled by Messier and his assistant, Pierre Méchain, grew to 110 objects.

They were a diverse lot. Among them were globular and open clusters, nebulae, supernova remnants, and huge galaxies beyond the edges of our own. Messier did go on to discover a handful of comets, but - ironically – he is much more famous for the list of non-comet objects he compiled. Since all of the objects on the list are fairly bright and easy to see with small telescopes, the list has become a favorite of amateur astronomers. The chart below shows some of the diversity of these objects:

Messier objects

Below is a chart of the sky illustrating the distribution of Messier objects across the sky:

Messier objects plot