During this period the moon reaches its full phase on Saturday December 6th. At this time the moon lies in the sky all night long and obscures all but the brightest meteors. Toward the end of this period the moon will approach its last quarter phase and will not be nearly as bright as when full. This will allow observers to view meteor activity as long as they keep the moon out of their field of view. The estimated total hourly meteor rates for evening observers this week is near 3 as seen from the northern hemisphere (45N) and 2 as seen from southern tropical latitudes (25S). For morning observers the estimated total hourly rates should be near 13 as seen from the northern hemisphere and 10 as seen from below the equator. 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. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brightest meteors will be visible from such locations. Rates are reduced during this period due to the bright moon.
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 6/7. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies at the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.
These sources of meteoric activity are expected to be active this week. The information is exact for December 7th but may be used in most cases for the entire week. Details on each radiant will again appear in next weeks outlook when the moonlight will be much more favorable.
|SHOWER||DATE OF MAXIMUM ACTIVITY||CELESTIAL POSITION||ENTRY VELOCITY||CULMINATION||HOURLY RATE||CLASS|
|RA (RA in Deg.) DEC||Km/Sec||Local Standard Time||North-South|
|Anthelion (ANT)||–||05:48 (087) +23||27||00:00||2 – 1||II|
|November Orionids (NOO)||Nov 29||06:28 (097) +15||44||01:00||<1 – <1||II|
|Monocerotids (MON)||Dec 13||06:40 (100) +09||41||02:00||1 – <1||I|
|Geminids (GEM)||Dec 13||06:56 (104) +33||34||02:00||1 – <1||I|
|Sigma Hydrids (HYD)||Dec 07||08:16 (124) +03||61||03:00||1 – 1||II|
|Puppid-Velids (PUP)||Dec 07||08:56 (134) -48||42||04:00||1 – 3||II|
|Eta Hydrids (EHY)||Dec 12||09:00 (135) +02||63||04:00||<1 – <1||IV|
|Dec. Leonis Minorids (DLM)||Dec 21||10:00 (150) +36||63||06:00||<1 – <1||IV|
|Psi Ursa Majorids (PSU)||Dec 05||11:24 (171) +43||61||06:00||1 – <1||IV|
|Dec. Chi Virginids (XVI)||Dec 17||12:28 (187) +04||69||08:00||<1 – <1||IV|
|Dec. Sigma Virginids (DSV)||Dec 24||12:44 (191) +08||68||08:00||<1 – <1||IV|