Messier marathon

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Table of images of all 110 Messier objects. Click on the picture for a larger version.

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A Messier marathon is an attempt, usually organized by amateur astronomers, to find as many Messier objects as possible during one night. The Messier catalogue was compiled by french astronomer Charles Messier during the late 18th century and consists of 110 relatively bright deep sky objects (galaxies, nebulae, and star clusters).

1 When and Where a Marathon is Possible
2 The Marathon
3 Organized Marathons
4 Criticism of Messier Marathons
5 External links
6 See also

[edit] When and Where a Marathon is Possible

The number of Messier objects visible in any one night varies depending on a few factors, including the location of the observer, the duration of daylight/nighttime, and the season (i.e., the position of the Messier objects relative to the sun).

[edit] Location

Because Messier compiled his catalog from a northern latitude, not all of the Messier objects are visible from the southern hemisphere. In particular, M81, M82, M52, and M103 make southern-hemisphere Messier marathons difficult because they are all located at a declination of 60° north or greater. Although a Messier marathon can be attempted from any northern latitude, low northern latitudes are best. In particular, a latitude of around 25° north lends the best possibility to complete a Messier marathon at the right time of year.

[edit] Season

At low northern latitudes, particularly around latitude 25° North, it is possible to observe all Messier objects in one night during a window of a few weeks in mid-March to early April. Within that time frame, ideal nights to attempt a Messier Marathon are those around the time of the new moon, when interference from the moon's light is minimal.

[edit] Other Times of Year

Less complete Messier Marathons can be undertaken at other times of the year, with the actual percentage of Messier objects seen depending upon season and location. In particular, there is a short timeframe around the fall equinox that most of the objects can be seen.

[edit] The Marathon

Typically an observer attempting a Messier marathon begins observing at sundown and will observe through the night until sunrise in order to see all 110 objects. The objects must be viewed in more or less a prescribed order. This corresponds to the order in which the objects set below the horizon. An observer starts with objects low in the western sky at sunset, hoping to view them before they dip out of view, then works eastward across the sky. By sunrise, the successful observer will be observing the last few objects low on the eastern horizon, hoping to see them before the sky becomes too bright due to the rising sun. The evening can be a test of stamina and willpower depending on weather conditions and the physical shape of the observer. Particularly crowded regions of the sky (namely, the Virgo Cluster and the Milky Way's galactic center) can prove to be challenging to an observer as well, and a Messier marathon will generally budget time for these regions accordingly.

[edit] Organized Marathons

Marathons are typically organized by a local astronomy organization or astronomical society as a special type of star party. These are usually attempted at least once every year. Some clubs issue certificates either for participation or for achieving a set number of objects.

[edit] Criticism of Messier Marathons

While many amateur astronomers relish the challenge of completing a Messier Marathon, others do offer criticism, particularly that undertaking such an observing race does not allow for much time to enjoy or study any one object. (During the springtime marathon window, the rate of observing averages out to finding more than a dozen objects per hour of the night.) Proponents counter that the marathon is designed along the lines of a sprint to complete a checklist rather than to offer thorough study, and that undertaking a marathon can help hone an observer's ability to relocate an object later for further study. An additional benefit posited is that an observer will see the entire catalog of Messier objects, which they might not otherwise do even over a span of months or years.