The objects in the Messier List are distributed throughout the night sky visible from mid-northern latitudes. None of the objects fall in the area between Pisces and Aquarius, so when the Sun moves between those constellations in late March every year, it allows observers to see all 110 of the Messier objects between dusk and dawn on a single night. The “Messier marathon” itself was invented independently by American astronomers Tom Hoffelder, Don Machholz and Tom Reiland, according to Machholz’s website.
The most southerly Messier object is in Scorpius, and the most northerly one is in Ursa Major. For this reason, you can see all 110 objects only from locations on Earth between about 20 degrees south and 55 degrees north latitude. Observers in the southern United States around 25 degrees north have an advantage for viewing the objects observable only after dusk and before dawn because the Sun rises and sets more vertically near Earth’s Equator, offering shorter twilight periods.
To better see the fainter objects, pick a moonless night within a day or two of the new Moon on Saturday, March 13. A clear sky all night long is a must, so check the forecast and choose the night that offers the best conditions. If more than one night looks promising, make your attempt on the first night, so you have the option for a second try.
Pick an observing site free from artificial lights and light pollution, with open sight lines to the horizon, especially to the west and the southeast. A higher elevation site will give you more time to observe the low objects. Bring warm clothes, and stock up on snacks and drinks — you’ll be awake all night!
Be sure to set up your telescope and organize your other equipment well before sunset. If you are using a GoTo telescope, align it in advance and be sure to have an adequate, long-lasting power source for it. If you can’t star-align the telescope before sunset, consider starting your marathon a few hours before dawn and observe the morning objects. Then leave the telescope aligned all day and resume your session at sunset. You’ll still have run your marathon within 24 hours.
The Messier List viewing plan
We can learn plenty from astronomers who have carried out Messier marathons in the past. Here’s a website with a planning tool from RASC’s Calgary Centre. The objects aren’t viewed in the order they set, because brighter objects can be picked out during twilight, while dimmer objects need more darkness. (Be careful not to confuse the viewing order with the Messier number!)
To start your marathon, you will need to quickly catch the objects that set in the west after sunset, specifically the dim galaxies M77 and M74. By the time the sky has grown dark enough to see them, they will be low in the west, so limit the time spent on the first galaxy so as not to miss the other one. Immediately after viewing those two, find M33, the large, face-on spiral galaxy in the constellation Triangulum, and then the Andromeda galaxy trio of M31, M32 and M110.
From this point, you will have time to work your way systematically across the sky from west to east. As you do so, more objects will rise in the east. By late evening, you should arrive at the Virgo Cluster of galaxies. When you have viewed the 17 Messier objects there, you can take a break until the next group rises into view at around 3 a.m. local time.
The final wave of objects includes M55, M75, M72, M73 and M2, which rise in the predawn. The last object, the globular cluster M30, will rise in the east as dawn starts to break — so it will be a challenge to see that object. Observers farther south will have an advantage here.
And that’s it! Whether you run the entire Messier Marathon, fall a wee bit short, or only sample a portion of it, you’ll enjoy a wonderful adventure under the stars, seeing the best that the night sky has to offer. And, hey — there’s always next year!
Chris Vaughan is a science writer, geophysicist, astronomer, planetary scientist and an “outreach RASCal.” He writes Astronomy Skylights, and you can follow him on Twitter at @astrogeoguy. He can also bring his Digital Starlab portable inflatable planetarium to your school or other daytime or evening event. Contact him through AstroGeo.ca to tour the universe together.