During this period the moon reaches its new phase on Wednesday January 1st. At this time the moon will lie near the sun and will be invisible at night. This weekend the waning crescent moon will rise during the late morning hours and should not interfere with meteor observing. The estimated total hourly meteor rates for evening observers this week is near 4 for observers located in the northern hemisphere and 3 for those viewing south of the equator. For morning observers the estimated total hourly rates should be near 16 for observers in the northern hemisphere and 10 for observers situated south of the equator. 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 28/29. 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:
Now that the activity from particles produced by comet 2P/Encke has ceased encountering the Earth, the Taurid showers for 2013 are over and we resume reporting activity from the Anthelion (ANT) radiant. This is not a true radiant but rather activity caused by the Earth’s motion through space. As the Earth revolves around the sun it encounters particles orbiting in a pro-grade motion that are approaching their perihelion point. They all appear to be radiating from an area near the opposition point of the sun, hence the name (Anti)helion. These were once recorded as separate showers throughout the year but it is now suggested to bin them into their category separate from true showers and sporadics. This radiant is a very large oval some thirty degrees wide by fifteen degrees high. Activity from this radiant can appear from more than one constellation. The position listed here is for the center of the radiant which is currently located at 07:20 (110) +21. This position lies in central Gemini, very close to the position occupied by the 4th magnitude star Wasat (Delta Geminorum). Anthelion activity may also appear from eastern Taurus, northeastern Orion, Cancer, Canis Minor, Monoceros, southern Lynx, or southern Auriga. The bright planet Jupiter would also serve as a useful guide as it only lies a few degrees west of the center of this source. This radiant is best placed near midnight local standard time (LST) when it lies on the meridian and is highest in the sky. Rates at this time should be near 1 per hour as seen from the northern hemisphere and less than 1 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 Hydrids (AHY) are active from December 27th through January 8th. Peak activity occurs on December 31st from a radiant located at 08:20 (125) -07. This position lies in extreme western Hydra, fifteen degrees west of the second magnitude star Alphard (Alpha Hydrae). Rates would most likely be near one per hour, no matter your location. The Alpha Hydrids are best seen near 0200 LST when the radiant lies highest above the horizon. At 45 km/sec. the Alpha Hydrids produce mostly meteors of medium velocity.
The January Leonids (JLE) were discovered by Dr. Peter Brown using a meteoroid stream survey based upon the Canadian Meteor Orbit Radar data. This weak shower is active from January 1st to 5th with maximum activity occurring on January 1st. On the 1st the radiant is located at 09:46 (147) +24. This position lies in western Leo just west of the third magnitude star Algenubi (Epsilon Leonis). This is a very minor display with hourly rates of less than one expected, even at maximum activity. They are best seen near 0300 LST when the radiant lies highest above the horizon. At 54 km/sec. the January Leonids (JLE) produce mostly meteors of medium-swift velocity.
The December Leonis Minorids (DLM) are active from a radiant located at 11:16 (169) +27. This position lies in northern Leo, 6 degrees north of the third magnitude star Zosma (Delta Leonis). These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. This shower peaked on December 17th so current rates would be near 1 per hour as seen from the northern hemisphere and less than 1 per hour as seen from south of the equator. At 64 km/sec. the December Leonis Minorids produce mostly swift meteors.
The Coma Berenicids (COM) are best seen from December 23 through January 2. Maximum activity occurs on December 30 when this shower is the fourth strongest in the sky. The current radiant position lies at 12:32 (188) +10. This position lies northern Virgo, 8 degrees west of the third magnitude star Vindemiatrix (Epsilon Virginis). Current hourly rates should be near 2 shower member per hour no matter your location. These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. At 69 km/sec. The Coma Berenicids would produce mostly swift meteors.
The December Sigma Virginids (DSV) was discovered by John Greaves using the data of SonotaCo. IMO video cameras confirmed that this source is active during most of December and into the first week of January. Visual observers have their best chance at catching these meteors from December 17 through January 1st. Peak rates occur near December 25th. The current radiant location is at 14:08 (212) +03 which places it in northern Virgo just northeast of the fourth magnitude star Tau Virginis. Current hourly rates would near 1 shower member no matter you location. These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. At 69 km/sec. the December Sigma Virginids would produce mostly swift meteors.
The Quadrantids (QUA) or January Bootids are active from January 1st through the 10th. A sharp maximum is predicted to occur near 2000 Universal Time on the 3rd. Unfortunately this corresponds to the afternoon hours across North America and early evening hours in Europe. This timing is most favorable for eastern Asia where the radiant will lie high in a dark sky at the time of predicted maximum. Observers in Europe may be able to see 30-40 Quadrantids per hour on the morning of the 4th, depending on their latitude. For North America, rates would only be 20-30 per hour on the mornings of the 3rd and the 4th, again depending on your latitude. At maximum the radiant is located at 15:21 (230) +49. This position lies in a barren region of extreme northern Bootes, ten degrees northeast of the fourth magnitude star Beta Bootis. As seen from the northern hemisphere, this area of the sky lies close to the northern horizon during the evening hours. Only after midnight does the radiant rise high into the northeastern sky. As seen from the southern hemisphere, this radiant is poorly placed as it only clears the northeastern horizon just before the start of morning twilight. Observers near the equator are a bit better off as the radiant rises at least 1 hour before the start of morning twilight. At 42 km/sec. the Quadrantids produce meteors of medium velocity. During exceptional activity some Quadrantid fireballs may be witnessed. Rates away from the night of maximum are poor, especially near the extremes of the activity period
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 3 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 6 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.
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|
|Anthelions (ANT)||–||07:20 (110) +21||29||00:00||1 – <1||II|
|Alpha Hydrids (AHY)||Dec 31||08:20 (125) -07||45||01:00||1 – 1||IV|
|January Leonids (JLE)||Jan 01||09:46 (147) +24||54||02:00||<1 – <1||IV|
|Dec. Leonis Minorids (DLM)||Dec 17||11:16 (169) +27||64||04:00||1 – <1||II|
|Coma Berenicids (COM)||Dec 30||12:32 (188) +10||69||05:00||2 – 2||II|
|Dec. Sigma Virginids (DSV)||Dec 25||14:08 (212) +03||69||07:00||1 – 1||IV|
|Quadrantids (QUA)||Jan 03||15:21 (230) +49||42||08:00||<1 – <1||I|