During this period the moon reaches its new phase on Sunday February 10th. At this time the moon is located near the sun and is invisible at night. As the week progresses the waxing crescent moon will enter the evening sky but will not interfere with meteor observing. The estimated total hourly meteor rates for evening observers this week is near three as seen from the northern hemisphere and five as seen from south of the equator. For morning observers the estimated total hourly rates should be near nine from the mid-northern hemisphere and eighteen from the mid-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.
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 February 9/10. 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.
The following showers are expected to be active this week:
The large Anthelion (ANT) radiant is currently centered at 10:16 (154) +09. This position lies in southwestern Leo, three degrees southeast of the first magnitude star Regulus (Alpha Leonis). These meteors may be seen all night long but the radiant is best placed near 0100 LST when it lies on the meridian and is highest in the sky. Rates at this time should be near two per hour as seen from the northern hemisphere and one per hour from south of the equator. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.
The Alpha Centaurids (ACE) are active from a radiant located at 14:10 (212) -60. This position lies in southeastern Centaurus, very close to the position occupied by the first magnitude star Hadar (Beta Centauri). These meteors cannot be seen north of the northern tropical regions. They are best seen from mid-southern latitudes where the radiant lies high in the sky near 0500 local summer time. This shower peaked on February 8th so current rates would be near three per hour as seen from the southern hemisphere. At 56km/sec. the Alpha Centaurids would produce mostly swift meteors.
Activity from the Beta Herculids begins on Wednesday morning February 13th. This also happens to be the morning of maximum activity. This shower was discovered by Juergen Rendtel and Sirko Molau using data from the IMO video database. This shower is active from the 13th through the 19th. On the 13th the radiant is located at 16:27 (247) +24. This position is located in western Hercules, three degrees north of the third magnitude star Kornephoros (Beta Herculis). These meteors are best seen near during the last dark hour before dawn when the radiant lies highest above the horizon in a dark sky. Rates would mostly likely be less than one shower member per hour, no matter your location. At 56 km/sec. the Beta Herculids would produce mostly swift meteors.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately seven 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 fourteen per hour as seen from rural observing sites and four per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.
The table below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning .
|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|
|Anthelions (ANT)||-||10:16 (154) +09||30||01:00||2 – 1||II|
|Alpha Centaurids (ACE)||Feb 08||14:10 (212) -60||56||04:00||<1 – 3||II|
|Beta Herculids (BHE)||Feb 13||16:27 (247) +24||56||06:00||<1 – <1||IV|