During this period the moon reaches its full phase on Friday February 14th. At this time the moon will lie opposite the sun and will remain above the horizon all night long as seen from mid-northern latitudes. This weekend the waxing gibbous moon will set during the early morning hours and will allow several hours of viewing under optimal conditions before the onset of dawn. This window of opportunity will shrink by approximately 45 minutes with each passing day until the moon lies above the horizon all night long toward the end of the week. The estimated total hourly meteor rates for evening observers this week is near 3 for observers situated at mid-northern latitudes and 4 for observers viewing from the southern tropics (latitude 25 S.). For morning observers the estimated total hourly rates should be near 9 for observers situated at mid-northern latitudes and 20 for observers viewing from the southern tropics. 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. Evening rates are reduced during this period due to moonlight. 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 February 8/9. 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 sources of meteoric activity are expected to be active this week:
According to Sergei Shanov, there is the possibility that the Earth may encounter some debris from comet 45P/Honda-Mrkos-Pajusakova on February 11, near 9:37 Universal Time. Activity is expected to be weak and even worse than that, the position of 21:54 (328) -15 places it in northeastern Capricornus, just a few degrees from the sun! This situation makes visual sightings nearly impossible but observers may attempt to listen for any activity near the time of maximum activity. At the time of maximum activity the sun will be above the horizon for nearly the entire eastern hemisphere, therefore radio observers in the eastern hemisphere might attempt to verify any activity. These meteors would have a slow entry velocity of 23 km/sec.
The center of the large Anthelion (ANT) radiant is currently located at 10:20 (155) +09. This position lies in southwestern Leo, 3 degrees southeast of the 1st magnitude star known as Regulus (Alpha Leonis). Due to the large size of this radiant, Anthelion activity may also appear from Cancer, Sextans, northwestern Hydra as well as Leo. This radiant is best placed near 0100 local standard time (LST), when it lies on the meridian and is located highest in the sky. Rates at this time should be near 1 no matter your location. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.
The Alpha Centaurids (ACE) are active from January 28 though February 21, with maximum activity occurring on February 8. The radiant is currently located at 14:04 (211) -59. This position lies in southeastern Centaurus just north of the brilliant 1st magnitude star known as Hadar (Beta Centauri). Due to the southern declination of this radiant, these meteors are not visible beyond tropical latitudes in the northern hemisphere. Current rates would be near 5 per hour as seen from the southern hemisphere and less than 1 from the northern hemisphere. These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. At 56 km/sec. the Alpha Centaurids would produce mostly swift meteors.
Activity from the Beta Herculids begins on Thursday 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 near 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 7 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 2 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 14 per hour as seen from rural observing sites and 3 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening rates are reduced due to interfering moonlight.
The table below presents a list of radiants that are expected to be active this week. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.
|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|
|45Pids||Feb 11||21:54 (328) -15||23||12:00||<1 – <1||III|
|Anthelions (ANT)||–||10:20 (155) +09||29||01:00||1 – 1||II|
|Alpha Centaurids (ACE)||Feb 08||14:04 (211) -59||56||05:00||<1 – 5||II|
|Beta Herculids (BHE)||Feb 13||16:27 (247) +24||56||07:00||1 – 1||IV|