During this period the moon wanes from being full to nearly one-half illuminated. This weekend the nearly full moon will obscure all but the brightest meteors. Conditions will sightly improve with each passing night as the phase wanes and the moon rises later each night. The estimated total hourly meteor rates for evening observers this week is near 3 as seen from mid-northern latitudes (45N) and 2 as seen from tropical southern locations (25S). For morning observers the estimated total hourly rates should be near 8 as seen from mid-northern latitudes (45N) and 6 as seen from tropical southern locations (25S). Rates are reduced during this period due to interfering moonlight. 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.
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 26/27. 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.
Details of each source will continue next week when a decrease in moonlight allows better viewing conditions.
|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)||–||07:12 (108) +22||30||01:00||1 – <1||II|
|Alpha Hydrids (AHY)||Dec 31||08:08 (122) +02||43||02:00||<1 – <1||IV|
|c Velids (CVE)||Dec 29||09:04 (136) -54||39||03:00||<1 – <1||II|
|January Leonids (JLE)||Jan 02||09:46 (147) +24||59||04:00||<1 – <1||II|
|Dec. Leonis Minorids (DLM)||Dec 21||10:48 (168) +27||63||05:00||1 – <1||II|
|Coma Berenicids (COM)||Dec 31||12:00 (180) +15||70||06:00||<1 – <1||II|
|Dec. Sigma Virginids (DSV)||Dec 24||13:48 (207) +03||68||08:00||<1 – <1||IV|
|Dec. Alpha Draconids (DAD)||Dec 30||14:44 (221) +53||42||09:00||<1 – <1||I|
|Quadrantids (QUA)||Jan 04||15:12 (228) +50||41||10:00||1 – <1||I|