Instructions for the One-Page Messier Marathon Sheets

Here are Messier Marathon guides and Half Marathon guides, as well as sky charts covering the first half of the night sky (before midnight, chart 1) and second half of the night sky (after midnight, chart 2). These charts, which cover before and after midnight, provide a concise way of managing your Messier Marathon. The sheets give a logical order to find the objects; provide a checklist to keep track of what has been found; and to show at a glance when things rise and set. All you really need is the one-pager, a pretty basic star chart (maybe just one-page version here), and some persistence to complete a successful Marathon and see at least 100 of the objects.

Because there is a lot of stuff crammed into the guide sheets, some beforehand preparation can make your observing time much more productive. Putting all this information on a single sheet makes things quite crowded so a little explanation might help. There are two columns of objects. The order of observation goes from top to bottom through the left column then the right.

Each column has 12 different pieces of information. The column headings and descriptions are:

• Num. - Messier object number
• R.A. - Right ascension in hours and minutes
• Dec - Declination in degrees and minutes
• Rise - Rising time of the object based on a 24-hour clock.
• Set - Setting time. For those objects that are circumpolar (always visible) the transit time, that is the time when they are highest in the sky, is listed along with the indicator "Trans."
• Con - Abbreviation of the constellation in which the object lies. Most of them are pretty obvious (Ori for Orion, CMa for Canis Major) but some are obscure (Cnc for Cancer, Sge for Sagitta.) In any event, they are usually included with any star chart or handbook.
• NGC - NGC number of the object [M45 (Pleiades) and M40 (a double star) do not have NGCs.]
• Typ - Abbreviation of object type: OC - open cluster, Gx - galaxy, Pl - planetary nebula, Gb - globular cluster, Nb - emission nebula, S2 - double star, and CN - cluster with nebulosity.
• Mag - Visual magnitude of the object. The dimmest naked eye star is around 6th magnitude. For each increase of 1.0 in magnitude, the brightness decreases by a factor of 2.5.
• Size - Angular size of the object in arc minutes. For comparison, the Moon averages about 32 arc minutes in size while Jupiter is 3/4 arc minute.

Combining size and magnitude gives an idea of appearance. For example, M101 is a bright (Mag. 7.7) but large (26.9 arc minutes) galaxy making the surface brightness low so it is hard to find in a small telescope. M82 is smaller (11.2 arc minutes) and dimmer (Mag. 8.4) but has over three times the surface brightness making it easier to find.

• Found - This column is simply a checkbox to keep track of which objects have been found.

The last section has a number of vertical gray and white bars. At the top are numbers ranging from 20 to 24 and then from 1 to 6. The numbers refer to the hour of the night and each vertical bar (either gray or white) is one hour of time. The bars range from sunset to sunrise. Each object has a horizontal black line crossing the gray and white bars to show when the object is visible. This is perhaps the most useful section since it allows you to determine at a glance what objects are rising or setting through the night. Circumpolar objects (above +55 degrees declination) never set. For these, a dashed line is used, but are best observed around the transit time listed instead of a rise/set time.

The objects are not sorted simply by the rising and setting times but are grouped in areas of the sky to make it relatively easy to hop from one to the other. I will generate a set of charts showing these groupings and suggesting how to go from object to object.