The Meteor Activity Outlook is a weekly summary of expected meteor activity written by Robert Lunsford, Operations Manager of the American Meteor Society and contributor to this blog. The original unedited version of this week’s Meteor Activity Outlook can be found at the American Meteor Society’s site.
No matter where you live, the first half of December provides some of the best meteor activity of the year. In the northern hemisphere the sporadic rates are still strong plus you can also count on strong activity from the Geminids, which peak on December 14. There are also several minor radiants that add a few meteors each hour. All of these centers of activity are located high in the sky during the early morning hours this time of year. Much of the activity mentioned above can also be seen from the southern hemisphere. While the sporadic rates are not as strong as those seen from the north, they are stronger than the previous months and heading for a maximum in January. The warm, but short summer nights south of the equator make for some great viewing as long as the moon does not interfere.
During this period the moon reaches its full phase on Tuesday December 21st. At this time the moon lies opposite the sun and is above the horizon all night long from most locations. This is the worst time to attempt to view meteor activity as the bright moonlight will obscure all but the brightest meteors. The estimated total hourly rates for evening observers this week is ~3 from the northern hemisphere and ~2 for observers south of the equator. For morning observers the estimated total hourly rates should be ~10 from the northern hemisphere and ~9 as seen from the southern hemisphere. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Rates are reduced during this period due to moonlight.
The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning December 18/19. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.
The following showers are expected to be active this week. The detailed descriptions will be continued next week when the moonlight is not as intense.
Shower Name RA DEC Vel Rates km/s NH SH ANT Antihelions 06h 40m +23 30 2 2 MON Monocerotids 07h 08m +07 41 <1 <1 GEM Geminids 07h 56m +31 35 1 1 HYD Sigma Hydrids 08h 56m +00 61 <1 <1 DLM Dec Leonis Minorids 10h 44m +31 71 1 <1 COM Coma Berenicids 11h 48m +18 65 2 <1 URS Ursids 14h 12m +75 33 <1 <1 RA - Right Ascension DEC - Declination Vel - Velocity relative to Earth (in km per sec) Rates - Rate of visible meteors per hour from a dark site NH - Northern Hemisphere SH - Southern Hemisphere