January sees a peak of sporadic activity for the southern hemisphere while rates seen north of the equator begin a steady downward turn that continues throughout the first half of the year. The sporadic activity is good for both hemispheres, but not as good as it was for northern observers in December. Once the Quadrantids have passed the shower activity for January is very quiet. During this period the moon reaches it new phase on Monday January 26th. At this time the moon lies in the vicinity of the sun and is invisible at night. Late next week the waxing crescent moon appears in the evening sky but sets soon after the end of twilight. Thus there is no lunar interference during this period. The estimated total hourly rates for evening observers this week is near two no matter your location. For morning observers the estimated total hourly rates should be near ten for those located in the mid-northern hemisphere (45 N) and twelve for those viewing from the mid-southern hemisphere (45 S). Locations between these two extremes would see activity between the listed figures. These rates assume that you are watching from rural areas away from all sources of light pollution. 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.
The radiant positions and rates listed below are exact for Saturday night/Sunday morning January 24/25. 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 anytime 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.The following showers are expected to be active this week:The wide Antihelion (ANT) radiant is now centered at 09:12 (138) +15. This area of the sky lies on the Leo/Cancer border, twelve degrees northwest of the first magnitude Regulus (Alpha Leonis). This radiant is best placed near 0100 LST, when it lies on the meridian and is located highest in the sky. Due to the large size of this radiant, any meteor radiating from Cancer or western Leo could be a candidate for this shower. Rates at this time should be near three per hour as seen from the northern hemisphere and two per hour for observers located south of the equator. With an entry velocity of 30km/sec., the average Antihelion meteor would be of medium-slow speed.Later next week the Alpha Centaurids (ACE) become active from a radiant located at 12:56 (194) -55. This area of the sky is located in southern Centaurus, six degrees southeast of the second magnitude star Gamma Centauri. Current rates would be less than one shower member per hour. These meteors are best seen near 0500 local standard time when the radiant lies highest above the horizon. This shower is not visible north of 35 degrees north latitude and also poorly seen in the northern tropics. The southern hemisphere offers a much better view of this activity as the radiant lies much higher in the southern sky. Those located at high southern latitudes will actually encounter morning twilight before the radiant reach esculmination. At 56 km/sec. the Alpha Centaurids will usually produce meteors of swift velocity.The last remnants of the Coma Berenicids (COM) will be seen this week from a radiant located at 13:00 (195) +16. This area of the sky is located in southeastern Coma Berenices, two degrees southwest of the fourth magnitudes tar Alpha Comae Berenices. These meteors are best seen near 0500 LST when the radiant lies highest above the horizon. Rates should currently be 30">less than one per hour no matter your location. At 64 km/sec. the Coma Berenicids will usually produce meteors of swift velocity. As seen from the mid-northern hemisphere (45N) one would expect to see approximately thirteen Sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near two per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near fifteen per hour as seen from rural observing sites and three per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.The table below presents a summary of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning but may be used all week.
Antihelion (ANT) - 09:12 (138) +15 Velocity -30km/sec.
Hourly Rates - Northern Hemisphere - 3
Southern Hemisphere - 2
Alpha Centaurids (ACE) 12:56 (194) -55 Velocity - 56km/sec.
Hourly Rates - Northern Hemisphere - <1> (COM) 13:00 (195) +16 Velocity - 64km/sec.
Hourly Rates - Northern Hemisphere - <1
http://www.amsmeteors.org/showers.html#X2009
Clear Skies!
Robert Lunsford American Meteor Society
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