The Ultimate Guide to Conquering the Messier Marathon

After a long, cold, and wet winter, most people throughout the Northern Hemisphere will be rejoicing when spring returns. For amateur stargazers, spring means warmer temperatures, new constellations, and new celestial objects appearing in the sky. These changes bring the annual celestial viewing event that many observers look forward to each year—the Messier Marathon.

For those unfamiliar with this annual springtime event, this guide will introduce its history, the objects involved, and helpful observing tips, including some insightful information from Celestron's Northeast Regional Sales Manager, Ed McDonough, and Product Development Manager, Lance Lucero. In 2021, Ed participated in his first Messier Marathon and successfully observed 108 of the 110 deep-sky objects in the Messier catalog. Meanwhile, Lance participated in the 1990s and successfully observed all 110 Messier objects using a star atlas! If you're ready for a new observing challenge or want to re-ignite your passion for astronomy, why not participate in a Messier Marathon with your family and friends?

Who was Charles Messier?

Before we get into the details of the Messier Marathon, let's meet the man whose name will forever be associated with its namesake. Charles Messier was an eighteenth-century French astronomer and comet hunter who discovered at least thirteen comets and co-discovered several more. During a summer night in 1758, while searching for comets with his telescope, Messier observed a small, hazy object near the southern horn of the constellation Taurus. At first, he mistook this object for Halley's Comet, but he later determined it was not a comet but a stationary object. This fuzzy object would become the first entry in his new journal. Designated Messier 1 or M1, it was a remnant of a supernova outburst known today as the Crab Nebula that Chinese astronomers first saw in 1054. Messier kept a record of these fixed objects so that he and other comet hunters could distinguish between real comets from these non-moving fuzzy objects to avoid false reporting.

Messier Catalog

Today, countless amateur and professional astronomers refer to Charles Messier's journal, the Messier catalog. While the catalog does not contain all of the popular celestial targets, it does feature many of the brightest targets seen from the Northern Hemisphere because Messier conducted his observations from Paris.

In all, the Messier catalog features 110 entries called Messier objects. Each object is defined by an "M-code" Messier 1 or M1 through M110. There was controversy over M102 because Messier did not provide coordinates for this galaxy. Its original discoverer, Pierre Méchain, a fellow French astronomer and colleague of Messier, believed it was a duplicate of M101. Historical evidence has shown that M102 was a galaxy known as NGC 5866, which NASA also considers valid.

The Messier catalog consists of an asterism, a double star, elliptical galaxies, an irregular galaxy, lenticular galaxies, spiral galaxies, a Milky Way patch, diffuse nebulae, planetary nebulae, globular star clusters, open star clusters, and a supernova remnant. Most of these objects also have proper names. You might recognize The Great Orion Nebula (M42), Andromeda Galaxy (M32), the Great Globular Cluster in Hercules (M13), and the Ring Nebula (M57), to name a few.

Contrary to popular belief, Messier did not discover all the objects in his catalog. He found 40 plus of the largest and brightest objects with various small telescopes. Later on, other astronomers added objects to the catalog. The final entry, M110, joined the catalog in 1967, long after Messier's death. Here is the Messier catalog that astronomers use today.

What is a Messier Marathon?

In the 1970s, American astronomers Tom Holfelder, Donald Machholz, and Tom Reiland invented the "Messier Marathon," an annual all-night observing event with a "small viewing window" in March and early April. To complete the challenge, amateur astronomers try to locate and observe as many Messier objects as possible in a single night.

Because the Sun moves between Pisces and Aquarius during this time and no Messier objects are in this area, marathoners can observe all 110 objects between sundown and sunrise. Observers can attempt the Messier Marathon from most northern latitudes—low latitudes are considered ideal, particularly between approximately 20 degrees south and 55 degrees north latitude, worldwide.

Like a long-distance running event, the Messier Marathon takes preparation, the right gear, plenty of stamina, and a game plan to succeed. You wouldn't want to doze off in the middle of the night, would you? Viewing all 110 objects is not as easy as it may seem—even if you use a computerized GoTo telescope. The weather, sky conditions, moon phase, and terrain play significant roles.

Typically, the marathon begins when observers spot galaxies M77 and M74 low in the western sky at dusk before they vanish below the horizon. After confirmed sightings, observers move on to the next group of objects on the list and continue until dawn. Some regions of the night sky host many Messier objects. Sagittarius, for example, is home to 15 objects—the most of any constellation—so expect to spend a lot of time navigating the area. Virgo follows with eleven objects, Coma Berenices with eight objects, Ophiuchus and Ursa Major with seven each, and Canes Venatici and Leo with five objects each.

Those still awake before sunrise will observe their final objects low on the eastern horizon, most notably, globular cluster M30. You'll be racing the clock—hoping to catch a glimpse before the sky is overwhelmed by the imminent glow of dawn.

The ideal time for most people to participate in a Messier Marathon is during a new Moon or on the weekends closest to a new moon, from mid-March to early April. In 2023, the new Moon does not fall on a weekend; however, two-weekend observing opportunities fall within this window: March 17-18 and March 24-25, when the Moon's phase will be a thin crescent. Weekends are a great time to participate in the marathon, especially for those who stay up all night and don't have to report for work the following days.

Helpful Tips

The more you prepare, the better your chances of observing all 110 Messier objects. Here are some tips to help you get the most out of your Messier Marathon, especially if you are a first-timer:

1. Scout your location ahead of time. Some objects will be near the horizon, so consider your elevation and select a site with an unobstructed view of the horizon.
2. Get some good sleep during marathon day so you’re ready to pull an "all-nighter."
3. Refrain from eating too much before or during your marathon session, or you may become drowsy.
4. Dress for cold conditions as temperatures drop overnight. Having hot chocolate or coffee available is a great idea.
5. Observe with a buddy or family member. Your partner can help you confirm objects, especially the more challenging targets. In addition, it helps to have another person around in case someone dozes off.
6. If possible, observe from darker skies on a moonless or near-moonless night. Some objects are very faint.
7. Use a computerized GoTo or an app-enabled telescope with the largest aperture you can—at least 4" to 5". The larger the telescope, the easier it will be to spot fainter objects. Align your telescope the night before and hibernate it until the marathon begins. You do not want to align your telescope at the start of the marathon and lose precious time.
8. Conduct a dry run before the main event, so you can have an idea of some of the targets you'll be observing. It will be a good opportunity to make sure your equipment is in good working order.
9. Make sure that your batteries are charged and that you'll have adequate power to run your equipment throughout the night.
10. Have your target checklist on hand so that you can mark off your targets as you observe them.
11. Don't spend too much time observing some targets, especially the fainter ones, when the viewing window is limited during dusk and dawn. The sky may become too bright while you're still "hunting" for one target while the other gets lost in the glow or sets below the horizon.
12. Know when the Sun will set and rise for your location.
13. Use an app like Celestron's SkyPortal to help you locate Messier targets if you are not using a computerized telescope.
14. Use binoculars to spot some of the brighter Messier objects. But remember, your telescope should be your primary instrument.
15. Have fun! Not everyone will successfully observe all of the Messier objects in one night, but you can still enjoy the experience. Remember, you customize the marathon to fit your needs and abilities. For example, you may want to break up the marathon into smaller chunks and see all 110 objects over the course of the Spring season.

"We were using a Celestron 14" Edge HD CGX-L scope in probably 4.5-5 magnitude skies. It made seeing the objects pretty easy. It would take an 8" scope in probably 5.5-6 magnitude skies to do likewise. We actually got ahead of ourselves during our observing session and were able to take about a 90-minute break so the ‘after midnight’ objects could get high enough in the sky to observe. All in all, we saw 108 of 110 objects. At the start, M77 was low in the west and in the glare of some rapidly expanding Bradenton, Florida suburbs. We never saw it and barely saw the second object, M74. In the end, it was almost dawn before M30 was high enough in the sky even to try it. No chance, as there was just too much light at that point. That one is still a real head-scratcher. The best advice, as always, is to get to dark skies!"

Celestron employee Lance Lucero also reflected on his first Messier Marathon.

“When I did this back in the late 90s, the use of 'newfangled digital setting circles' and 'fancy computerized mounts' were strictly frowned upon. The idea drilled into me by my friend (and astronomy mentor at the time) was that you had to manually find these objects using a finderscope and your trusty 'Sky Atlas 2000'. He took me out to Joshua Tree. I used his old fork mounted, orange tube C11. He was a veteran of numerous Messier Marathons using larger aperture scopes and this time he wanted to try it using his 5” Unitron refractor. We managed to get them all. To me the hardest part of this was the Coma/Virgo clusters of galaxies. Under dark skies there were just too many fuzzy galaxies in the field of view of that C11 to be sure you had the right one centered. It took a lot of studying the star atlas to make sure you had it right. I will always remember how much fun it was to compare views of these deep sky objects through both scopes. It still makes me smile to think we did it 'the hard way'.”

Whether this is your first or tenth Messier Marathon, remember it is a fun challenge! If you are successful in viewing all 110 Messier objects, you rock! If not—you still rock! You can always try again or make up your own rules and try to observe the ones you missed another time. How many folks can say they have seen all 110 Messier objects in their lifetime? That is a major accomplishment in itself.

Good luck, and stay awake. Bring it on!

Other articles you might be interested in: Ultimate Guide to Observing the Universe