For Charles Messier, star clusters were a nuisance. The French astronomer was mainly interested in comets. In the 18th century, finding a comet could bring fame and fortune – kings sometimes awarded medals and fat stipends for their discovery.

Through a telescope, star clusters could resemble comets. Messier and others might spend time following a cluster, only to find out that it wasn’t the prize. So Messier compiled a catalog of clusters and similar nuisances – a list of objects to ignore.

Four of the clusters follow a narrow path near Canis Major, the big dog: M46, 47, 48, and 50 – a Messier “highway.”

Although they’re close together in our sky, the clusters are not close together in space. Their distances range from about 1600 light-years to more than five thousand. So there’s no relationship among them.

They appear close together because they all lie along the Milky Way – the glowing outline of the disk of the Milky Way Galaxy. In that direction, we’re looking into the most densely populated region of the galaxy, so we see many more stars and star clusters – including the “pesky” clusters cataloged by Charles Messier.

The clusters are in the southeastern quadrant of the sky as night falls. Look for Sirius, the brightest star in the night sky, due south. The clusters spread out to the left and upper left of Sirius. All of them are easy targets for binoculars.

Script by Damond Benningfield