Each March, star gazers emerge from winter hibernation for the Messier marathon, a one-night, all-you-can-see tour of the catalog first compiled over 200 years ago as a list of objects to avoid while comet hunting. It’s all about the numbers, how many you can see: 100, 108, 109  even 110 , but numbers are just the metric. It’s fundamentally about your deep-sky observing skills, your star-hopping ability, and basically how well you know the sky. And while a lone observer can undertake it, most often this is an astro-social affair, which make the competition to see the most objects all the more keen. As a warm-up, check your own knowledge of the Messier objects with this quiz. Move your mouse over the Messier monogram button  to reveal the answer.

How many did Messier actually observe himself?  How many are listings of objects discovered by contemporary colleagues?  How many are just oddballs, mistakes or duplicates? 

Next, these questions pertain to the position of the Messier objects on the celestial sphere. Which one is the northernmost?  Southernmost?  Which are the most “west” and most “east” in terms of right ascension?  Why are there none south of declination -35°?  Which two form the closest pair?  Which one is the most isolated?  Where is the densest concentration?  How many can be seen in one eyepiece at one time? 

These answers are specific to observing the Messier objects from a particular location, here, Tuckahoe State Park located at 38° 59' N and 75° 56' W. How many are always above the horizon, termed circumpolar?  Which are the first to tackle in the evening?  Which are the last in the morning?  Why is globular cluster M30 so challenging?  When are the most Messier objects overhead at once?  When are there the fewest? 

Finally, these can only be answered by you: Have you seen them all?  What’s your favorite Messier object?  Your least favorite or maybe the one you find hardest to see?  Which is the most rewarding to observe? 

Answers, solid advice, suggested dates and observing sequences can be found in Don Machholz’s The Observing Guide to the Messier Marathon, published by Cambridge University Press (2002). There are many other marathons to enjoy once you’ve tackled the Messier list. Another great printed resource is Howard Pennington’s The Year-Round Messier Marathon Field Guide (Willmann-Bell, 1997). While late March is optimal for most locations (for example, considering the moon's phase , 2003's prime weekend is Friday-Saturday 28-29 March ), many Messier objects are visible at any time of the year. For example, over 100 are visible from mid-northern latitudes in mid-October, when the sky clarity and nighttime low temperatures are often more favorable. In any event, don't forget coffee and late-night snacks!

Available on the web, two programs, both by Bev M. Ewan-Smith, are available to help in running your Messier Marathon. Given a date, the Messier Object Visibility Program will return a table of which objects  are visible from your location (use N 39 and W 76 for Tuckahoe). More tables and graphs are generated by the MESSMARA or COAA Messier Marathon Windows Application (scroll to the bottom of this link).  Also check the moon phase, deep night calendars and clear sky clock to plan your marathon. Good luck this month and clear skies!

Amazingly, all these trivial-sounding "factoids" reveal the structure of the universe. The distribution of Messier objects across the sky is certainly not random. Diffuse nebulae and open cluster trace the Milky Way’s spiral arms, while globular clusters swarm around the galactic center. Stepping up, the large, bright spirals like M31 and M33 are our neighbors, and the swaths of mixed elliptical and spiral galaxies in Virgo, Leo and Ursa Major hint at the most immense structures known.  Seeing all this from your backyard, much less in one night, is perhaps the most remarkable fact of all.

The monogram background and button were scanned from that printed in Kenneth Glyn Jones’s Messier’s Nebulae and Star Clusters, 2nd edition (1991, Cambridge). I’d love to hear your answers to these questions or especially if I’ve fouled-up an answer or two. Moondark is written by Doug Miller and published on the web and in the Delmarva Star Gazers'Star Gazer News. This document was last revised on 23 February '03. All text and images copyright © 2003 Douglas C. Miller, All Rights Reserved. This material may not be reproduced in any form without prior permission.