During this period the moon reaches its full phase on Thursday January 12th. At this time the moon will be located opposite the sun and will lie above the horizon all night long. This weekend the waxing gibbous moon will set during the early morning hours, allowing a few hours of observations under dark skies before the start of morning twilight. 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 13 as seen from mid-northern latitudes (45N) and 11 as seen from tropical southern locations (25S). Evening rates are reduced during this period due to lunar interference. 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 January 7/8. 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 center of the large Anthelion (ANT) radiant is currently located at 08:00 (120) +20. This position lies on the Gemini/Cancer border, 8 degrees southeast of the 1st magnitude star known as Pollux (beta Geminorum). Due to the large size of this radiant, Anthelion activity may also appear from Cancer, western Hydra, and Canis Minor as well as eastern Gemini. 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 3 per hour as seen from the northern hemisphere and 2 per hour from south of the equator. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.
The December Leonis Minorids (DLM) are active from a radiant located at 11:44 (176) +23. This position lies in northeastern Leo, 9 degrees north of the 2nd magnitude star known as Denebola (beta Leonis). These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. This shower peaked on December 20th so current rates would be less than 1 per hour no matter your location. At 63 km/sec. the December Leonis Minorids produce mostly swift meteors.
The Quadrantids (QUA) are active from December 28th through January 12th with maximum activity expected on January 3. The radiant is currently located at 15:32 (233) +49. This position lies in a blank area of northern Bootes, 10 degrees north of the 3rd magnitude star known as Nekkar (beta Bootis). Since we are well past maximum activity, current rates are less than 1 per hour. These meteors are best seen during the last hour before dawn when the radiant lies highest above the horizon in a dark sky. At 41 km/sec. the Quadrantids produce meteors of moderate velocity. These meteors are visible from the southern tropics but not seen from the deep southern hemisphere.
The Xi Corona Borealids (XCB) are a new shower discovered by Peter Brown and associates at the University of Western Ontario using radar. This shower is best seen from January 11-18, with maximum activity occurring on the 15th. At maximum the radiant is located at 16:36 (249) +30, which actually places it within the borders of Hercules, 2 degrees southwest of the 3rd magnitude star Zeta Herculis. These meteors encounter the atmosphere at 49 km/sec., which would produce meteors of average velocity. These meteors are best seen during the last few hours before dawn, when the radiant lies highest in a dark sky. This activity would be difficult to view from the southern hemisphere as the radiant lies low in the north at dawn. This is a weak shower not expected to reach 1 per hour, even at maximum activity. Being discovered by radar, expect these meteors to be on the faint side.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately 10 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 9 per hour as seen from rural observing sites and 1 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.
|DATE OF MAXIMUM ACTIVITY
|RA (RA in Deg.) DEC
|Local Standard Time
|08:00 (120) +20
|Dec. Leonis Minorids (DLM)
|11:44 (176) +23
|<1 – <1
|15:32 (233) +49
|<1 – <1
|Xi Corona Borealids (XCB)
|16:36 (249) +30
|<1 – <1