During this period the moon reaches its new phase on Thursday January 30th. At this time the moon will lie near the sun and will be invisible at night. This weekend the waning crescent moon will rise near 0200 local standard time (LST). It will be bright enough to cause some interference in viewing meteor activity. Luckily, one can look in another direction and practically eliminate this problem. The moon be be less of a problem with each passing night. The estimated total hourly meteor rates for evening observers this week is near 2 for observers situated at mid-northern latitudes and 3 for observers viewing from the southern tropics (latitude 25 S.). For morning observers the estimated total hourly rates should be near 10 for observers situated at mid-northern latitudes and 12 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. Morning rates are reduced slightly this week 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 January 25/26. 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:
The center of the large Antihelion (ANT) radiant is currently located at 09:16 (139) +15. This position lies in eastern Cancer, 12 degrees northwest of the 1st magnitude star known as Regulus (Alpha Leonis). Due to the large size of this radiant, Antihelion activity may also appear from western Leo, Sextans, northwestern Hydra as well as Cancer. This radiant is best placed near 0100 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 Antihelion meteor would be of slow velocity.
The January Comae Berenicids (JCO) were discovered by Dr. Peter Jenniskens and discussed in his book Meteor Showers and their Parent Comets. These meteors are active from January 20-27, with maximum activity occurring on the 23rd. The radiant is located near 12:40 (194) +15. This position lies in southern Coma Berenices, 6 degrees northwest of the 2nd magnitude star known as Vindemiatrix (Epsilon Virginis). These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. Current rates would be near 1 per hour no matter your location. At 65 km/sec. the January Comae Berenicids would produce mostly swift meteors.
Toward the end of this period the Alpha Centaurids (ACE) become active. This shower is active from January 28 though February 21, with maximum activity occurring on February 8. On January 28th, the radiant is located at 13:16 (199) -56. This position lies in southern Centaurus between the bright stars Mimosa (Beta Crucis) and Epsilon Centauri. These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. Current rates would be less than 1 per hour no matter your location. At 56 km/sec. the Alpha Centaurids would produce mostly swift meteors.
The Alpha Coronae Borealids (ACB) were discovered by John Greaves using data from SonotaCo Network Japan. These meteors are best seen from January 27 through February 5 with maximum activity occurring on January 28th. On the 27th, the radiant is located near 15:28 (232) +29. This position lies in western Corona Borealis, close to the position occupied by the 4th magnitude star known as Nusakan (Beta Coronae Borealis). These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. Starting Monday, this radiant will be the strongest in the sky, producing an average of 2 meteors per hour as seen from the northern hemisphere. Rates seen from south of the equator would be near 1 per hour. At 58 km/sec. the Alpha Coronae Borealids would produce mostly swift meteors.
Toward the end of this period the February Eta Draconids (FED) become weakly active. This shower was discovered by Dr. Peter Jenniskens and Peter Gural using data from a “CAMS” network located in northern California. This source is thought to be active from January 29 through February 9, with maximum activity occurring on February 4. The current location of this radiant is estimated to be 15:48 (237) +61. This area of the sky is located east of the “handle” of the Big Dipper between the 3rd magnitude stars Eta and Iota Draconis. These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. Due to the high northern declination (celestial latitude) these meteors are poorly seen from the southern hemisphere. Rates less than 1 are expected this week. At 36 km/sec. the February Eta Draconids would produce mostly medium velocity meteors.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately 6 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 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Morning rates are slightly lower during this period due to 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|
|Anthelions (ANT)||–||09:16 (139) +15||29||01:00||1 – 1||II|
|January Comae Berenicids (JCO)||Jan 23||12:40 (194) +15||65||04:00||1 – 1||IV|
|Alpha Centaurids (ACE)||Feb 08||13:16 (199) -56||56||05:00||<1 – <1||II|
|Alpha Coronae Borealids (ACB)||Jan 28||15:28 (232) +29||58||07:00||2 – 1||IV|
|February Eta Draconids (FED)||Feb 04||15:48 (237) +61||36||07:00||<1 – <1||IV|