Welcome to the 2003 International Meteor Organization (IMO) Meteor Shower Calendar. The year sees two of the "big three" major showers - the Perseids and Geminids - lost to bright moonlight, but the third, the Quadrantids, are well-placed, along with the alpha-Centaurids, eta-Aquarids, and Southern delta-Aquarids. Minor or uncertain sources like the delta-Leonids, June Bootids, alpha-Aurigids, alpha-Monocerotids, Coma Berenicids and Ursids also enjoy often moonless skies, amongst others. What the Leonids may do in 2003 needs checking as well. Do not forget that monitoring of meteor activity should ideally be carried on throughout the rest of the year, however! We appreciate that this is not practical for many observers, and this Calendar was devised as a means of helping observers deal with reality by highlighting times when a particular effort may most usefully be employed. Although we include timing predictions for all the more active night-time and daytime shower maxima, based on the best available data, please note that in many cases, such maxima are not known more precisely than to the nearest 1° of solar longitude (even less accurately for the daytime radio showers, which have only recently begun to receive regular attention again). In addition, variations in individual showers from year to year mean past returns are at best only a guide as to when even major shower peaks can be expected, plus as some showers are known to show particle mass-sorting within their meteoroid streams, the radio, telescopic, video, visual and photographic meteor maxima may occur at different times from one another, and not necessarily just in these showers. The majority of data available are for visual shower maxima, so this must be borne in mind when employing other observing techniques.
The heart of the Calendar is the Working List of Visual Meteor Showers (see Table 5, thanks to regular updating from analyses using the IMO's Visual Meteor Database, the single most accurate listing available anywhere today for naked-eye meteor observing. Even this can never be a complete list of all meteor showers, since there are many showers which cannot be properly detected visually, and some which only photographic, radar, telescopic, or video observations can separate from the background sporadic meteors, present throughout the year.
The IMO's aims are to encourage, collect, analyze, and publish combined meteor data obtained from sites all over the globe in order to further our understanding of the meteor activity detectable from the Earth's surface.