Stargazing is a hobby, and for some, a serious hobby. Appropriately enough, we use superlatives to describe space and the universe. And we not only talk about extremes, we sometime go to them in pursuit of the farthest, oldest, brightest and dimmest. The annual Messier marathon might even qualify as a form of "extreme observing." Here, the goal is to see, in one dusk to dawn session, all the 100+ clusters, nebulae and galaxies (and even a few mistakes) tabulated by comet-hunterCharles Messier. Given that Messier observed from Paris (at 48°N latitude) in the 18th century, it isn't surprising that all "his" objects are visible from mid-northern latitudes with telescopes modest by today's amateur standards. Many stargazer regard completing their M-list as a benchmark of accomplishment. And well they should: it usually takes a year or more of casual observing, starhopping and becoming familiar with the constellations and the seasonal changes in the sky.

Marathoners know that, under ideal conditions, it is possible to view all (or nearly all) 110 of those objects in one night near the new moon closest to the beginning of spring. This year, the best weekend is March 28-29-30, right on the New Moon. Along with almost any telescope, good low horizons and little light pollution are necessary. Luck with the weather and the stamina to pull an "all-nighter" at the eyepiece are a must. You also need to have an observing strategy: the optimum sequence of objects and finder charts. No digital setting circles are allowed! Marathoning began as a club activity in the 70's and has gained considerable popularity. Often a social a get-together, it is frequently the year's kick-off event, a chance to retrieve telescopes from winter hibernation, and to anticipate summertime star parties. Even so, it does not appear to be widely known that Messier marathons (that's with a small "m") can be "run" at any time of year. True, the opportunity to see all the M's presents itself only in the spring, but did you know that 80% or more of them can be seen on any clear night?
 

This plot  shows the number of Messier objects visible from Tuckahoe State Park (38° 59' N) for every night, that is, above the horizon between the end and beginning of astronomical twilight. The maximum is 109 in March. M30 is the only object not visible. Surprisingly, the minimum is about 85 in mid to late December--precisely when we have the longest nights! Although the sky must be dark, the distribution is more important. The winter Sun blocks the view in and around Sagittarius, toward the center of the Milky Way. The marathoner's latitude is the other important constraint, determining how many objects are always above the horizon. There are eleven such circumpolar M-objects at Tuckahoe. But heading south raises objects with southerly declinations higher in the sky, increasing their window of visibility. South of 35°N, all 110 objects are visible during late March! From 20°S latitude, roughly Rio de Janeiro, at least 100 of the objects are visible on nights in May through August. Even in Auckland, New Zealand (almost 37°S), that hemisphere's fall and winter seasons have over 90 Messier objects to add to the many other gems of the southern skies.

There are two excellent guides to the Messier marathon. Comet hunter Don Machholz has published the Messier Marathon Observer's Guide Handbook and Atlas (1994, MakeWood Products, also Sky Publishing Corp.). As the subtitle says, it is a complete guide to running a marathon, with historical notes, explanations of seasonal and latitudinal variations, suggested dates and finder charts for all objects. Harvard Pennington's The Year-Round Messier Marathon Field Guide was published late last year by Willmann-Bell, Inc. It too will will lead you through every step and detail needed make your marathon a winning one.
 

Moondark is written by Doug Miller and published both electronically and in hard-copy form in the Star Gazer News for the Delmarva Star Gazers. Please address comments and suggestions to dmiller@udel.edu. This document was last revised on 23 February 1998. Copyright © 1998 Douglas C. Miller, All Rights Reserved. This material may not be reproduced in any form without prior permission.