NAMN has prepared some basic star charts for those new to meteor observing. These are a set of four charts and are suitable for printing from the website (we suggest setting your printer to "landscape" when printing). They can then be taken out in the field with you for use in learning the sky. Each chart shows the basic constellation names and patterns, along with the magnitudes of certain "standard" stars. These can be used in helping you judge the magnitude or brightness of the meteors you see. There are many sources that use a list of star magnitudes, but it is much easier when learning to observe if you have some easy charts right in front of you!
Each "standard" star has a circle around it and has its magnitude listed beside it. To avoid confusion with dots used for faint stars, decimals have been omitted. For example, a brightness of 3.0 is listed as 30 and a brightness of 2.5 is listed as 25 on the charts. For any given field of view, a range of "standard" stars has been labeled so that you will have in front of you the means to estimate meteor magnitudes from about 0.0 to +5.5 magnitude. If there is no even magnitude star close by, one with a half magnitude has been labeled. Many observers use half magnitudes for estimating meteors, not just whole numbers. Beginners should note that the bigger the number, the fainter the star (and meteor). Small numbers, such as zero, and negative numbers, mean bright stars and meteors!
These charts also have basic sky coordinates marked on them in Right Ascension (RA) and Declination. The RA is given both in hours and degrees to make it easier to look up the general location of a specific meteor shower radiant. Note, however, that these charts do not replace a real star atlas - they are just intended as an easy reference guide while out in the field.
What we suggest is that you get several heavy plastic page covers and slip the four charts into these, two in each page cover. Then, you will be able to mark your night's meteor shower radiant positions on these with a black grease pencil which will rub off with tissue for re-use during your next observing session. The plastic covers will also keep your charts from getting damp from dew or frost.
The available charts are:
Map #1: RA 0 hours - RA 8 hours
(Pisces, Taurus, Orion, Gemini, Canis Major)
Map #2: RA 8 hours - RA 16 hours
(Cancer, Leo, Virgo, Libra)
Map #3: RA 16 hours - RA 0 hours
(Ophiuchus, Aquila, Cygnus, Capricornus, Aquarius)
Map #4: North Circumpolar
(Ursa Major & Minor, Cassiopeia, Cepheus, Draco)
A very important piece of information needed when making any visual observation of meteor activity is the limiting magnitude (LM) of your observing site. This is basically an indication of an observer's sky conditions, or how dark the sky is at their site. The most common method of determining the limiting magnitude is by making a count of the number of stars seen in one or more predefined areas in the sky. The charts used by NAMN are those published by the International Meteor Organization and are available at http://www.imo.net/visual/major01.html#table2
More information on estimating meteor magnitudes and limiting magnitudes can be found in the NAMN Observing Guide section of this website.