From the January 2012 issue

Take on a Messier 5K

Ease into the Messier Marathon by first attempting a shorter challenge.
By | Published: January 23, 2012 | Last updated on May 18, 2023
Begin with the Pleiades (M45) for your Messier 5K. See how many of the open cluster’s bright stars you can spy with your naked eyes. Most observers can count four, five, or six stars arranged in the shape of a dipper, but slightly darker skies may reveal a seventh star. Credit: John Johnson
For the recreational runner, the ultimate challenge is the marathon. The backyard astronomer has a similar lofty goal: the Messier Marathon. In this “race,” participants try to view as many of Messier’s 109 deep-sky objects as possible in a single night. A marathon — on the ground or in the sky — isn’t something the novice should attempt. In the running world, there is a race that’s appropriate for the beginner: the 5K. If you’re an astronomical newbie (or a veteran skygazer unwilling to commit to an all-nighter), I offer you a “Messier 5K.”

The targets in our Messier 5K are conveniently placed in the early evening sky. Their locations are plotted on the all-sky map you’ll find in the middle of this issue. Most of them can be viewed in binoculars, especially from a dark-sky site.

The starting line for the Messier 5K course is the Pleiades (M45). Once you’ve spotted this open cluster, off you go! From M45, you’ll run through M35, M37, M36, and M38. These open clusters are aligned in a row that winds from Gemini’s foot through Auriga’s heart. Each appears as a hazy puffball in binoculars and a sprinkle of starlight through small scopes.

The best road races offer a scenic course, and our Messier 5K is no exception. When you arrive at the Orion Nebula (M42), take a breather to admire one of the heavens’ most splendid wonders. Once you’re ready to return to action, move southeastward to pick up the star clusters M41 and M47. Higher up and visible as a patch of light midway between the twin stars Pollux and Castor and the “sickle” of Leo is the Beehive Cluster (M44).

Next, standing at the finish line are the galaxies M81 and M82, both located a staggering 11 million light-years away! You can resolve both in the same eyepiece field of your scope if you use a low magnification.

The night of Saturday, March 24, is the best date to complete your Messier 5K, just after a New Moon. Start your training for a Messier Marathon then!