April 5, 2020

A Messier Marathon.

Spring is deep sky season. As the weather becomes more temperate and the daylight/nighttime balance sits roughly equal worldwide, telescopes at star parties begin to sprout up like springtime daffodils. Now is the time to nab that obscure cluster, or attempt to spy that faint planetary nebula. We here at Astroguyz always try to spot one new object every observing session… but have you ever tried to see all the Messier objects… in one night?

Such is the realm what visual athletes call a Messier marathon. With a little practice, YOU can successfully observe the entire Messier catalog… in one night!

Background: In 1771, French astronomer Charles Messier published the first list of deep sky objects. The initial catalog contained 45 objects, and in Messier’s lifetime the eventual list was expanded to 103. Today’s list runs out to 110 objects, and is a hodge-podge assortment of galaxies, nebulae, asterisms and even a double star. Part of this stems from the terrible quality of the optics of the day, another is the fact  that Messier and other early astronomers had no idea what these fuzzy smudges were. Messier was also more interested in the gentlemanly pursuit of comet hunting, and there is much allegory and tradition that alludes to the fact that the motivation for the compilation was to identify these comet masquerading nebulosities.

A Full on Marathon: One of the prime reasons a complete Messier marathon is possible in the spring time is that no Messier objects lay from Right Ascension positions 21:40 to 23:20hrs, and only one lies before 0:40, extremely northern M52. This is roughly the same position that the sun occupies during the season leading up to the spring equinox. In fact, a good deal of the Messier objects lie in the direction of Virgo and Coma Berenices in the Great Virgo Cluster, and more still lie in Sagittarius and the galactic plane and along the Cygnus arm. Mid-to late March is the best season, and this year, the best window lies at the end of the month as the moon approaches new in early April. A complete list of optimal dates until 2050 can be seen here. Observer Tom Polakis constructed a list of optimal dates based on latitude; this demonstrates that an entire Messier Marathon is possible from 3° North to 42° North, with the optimal window being from 20° North for most of the month of March.

Like any marathon, you want to start strong out the gate, but pace yourself. One key to a successful first time marathon is to find objects in the correct order; the galaxies M77 and M74 will disappear soon after twilight; nab them first before moving on to the M31 region of objects. You’ll then have a more leisurely stroll through Orion, and then pace yourself through the catalog and perhaps set your morning alarm for the finish with the tougher objects in Aquarius and a twilight M30 in Capricornus.

A few words of note: Some controversy revolves around the exact identification of M102: most Messier aficionados accept the nearby NGC 5866 as one in the same.  A clear horizon to the west and southeast is also crucial. Be sure all equipment is in good working order, and all batteries fully charged and equipped with backups. I frequently keep batteries inside my jacket to keep them nice and warm and not dead by sunrise.

A mini: No time for a full Messier marathon? Over the years, several abbreviated lists of objects have cropped up some targeting seasons and others with a lean towards observability.

Variations: Some folks argue that the intention behind the Messier marathon may run counter to the spirit of astronomy. True, it doesn’t give you time to contemplate or study most of these objects, and some abhor its simple “astronomy as sport” approach. It does, however, give you a great overview of how our universe is organized; most soon grasp the structure of our galaxy and the relation of the ancient clusters and our view of the spiral arms, as well as the vantage point of those distant galaxy clusters. I like to approach the list from a historical standpoint; Messier and the Hershel’s had little idea of what they were looking at. (More on them next week!) A messier marathon can sharpen your skills as an observer and cross those faint fuzzies off of the ol’ bucket list… can YOU say you’ve seen all 110?  Most clubs that run a marathon work through the list via a two observer confirmation concept. Binocular or even visual marathon’s can be fun too; just don’t expect to nab all of the faint Messiers this way!

Been there, done that? NGC and IC catalogs are waiting. Some seasons, a “Solar System” marathon of planets could be in the offing… make sure to include Pluto for a true challenge! Some observers have even attempted a photographic Messier marathon via CCD imaging. I think a good personal twist would be to turn the GOTO drives off and find all 110 via the ye ole’ star hopping method. Now that would truly sharpen the deep sky skills…

Do get out there this spring season and give the Messier list a shot. We’d also like to hear your personal tales of triumph and tragedy in this endeavor as well as your own personal tips and tricks for observing these objects; feedback can make a good post great. Next week, we’ll look an early explorer of these deep sky objects, as we review Discoverers of the Universe!


  1. [...] Moon occurs on Thursday, March 22nd, and heralds the optimal time of year this week to conduct a Messier Marathon. Can you catch all 110 deep sky objects in one dusk ‘til dawn sprint? Give her a [...]

  2. [...] written about some tips and tricks to completing this challenge previously, as well as the optimal dates for carrying a marathon [...]

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