No matter where you live, the first half of December provides some of the best meteor activity of the year. Unfortunately this year the bright moon will hamper the viewing of this activity. In the northern hemisphere the sporadic rates are still strong plus you can also count on strong activity from the Geminids, which peak on December 13. There are also several minor radiants that add a few meteors each hour. All of these centers of activity are located high in the sky during the early morning hours this time of year. Much of the activity mentioned above can also be seen from the southern hemisphere. While the sporadic rates are not as strong as those seen from the north, they are stronger than the previous months and heading for a maximum in February. The warm, but short summer nights south of the equator make for some great viewing as long as the moon does not interfere.
During this period the moon waxes from being half illuminated to full. This weekend the waxing gibbous moon will set during the early morning hours allowing a few hours of viewing in dark conditions between moon set and the start of dawn. As the week progresses the waxing gibbous moon becomes more of a problem as the window of dark conditions shrinks to zero by the end of the week. The estimated total hourly meteor rates for evening observers this week is near 3 as seen from the northern hemisphere (45N) and 2 as seen from southern tropical latitudes (25S). For morning observers the estimated total hourly rates should be near 10 no matter your location. 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. Evening rates are reduced during this period due to the bright moon.
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 November 29/30. 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 December Phoenicids (PHO) are a periodic shower that rarely produces noticeable activity. The only impressive display produced so far by this shower occurred in 1956 when ZHR’s were near 100. There is the possibility that in 2014, that the Earth may encounter strong activity from the Phoenicids. A prediction by Mikiya Sato and Junichi Watanabe indicates the the Earth will pass through several dust trails of asteroid 2003 WY25 (formally comet D/1819 W1 Blanpain) between the hours of 23:30 December 1 and 01:30 December 2 Universal Time. This 2 hour bracket of time favors much of the populated regions of the world except those bordering the Pacific Ocean and eastern Asia. The most favorable locations are South America and Africa where the radiant lies high in the sky at the time of the expected maximum activity. Normally the Phoenicid radiant lies far to the south in the constellation of Phoenix. The radiant position for this outburst is actually located further north at 00:32 (020) -27. This position lies in northern Sculptor, 10 degrees southwest of the 2nd magnitude star known as Diphda (Beta Ceti). At only 10 km/sec. the Phoenicids produce extremely slow meteors.
The December Phi Cassiopeiids (DPC) were discovered by Dr. Peter Jenniskens and are active from November 26 through December 5th. Maximum activity occurs on December 1st when the radiant is located at 01:33 (023) +53. This area of the sky is located in southern Cassiopeia, 3 degrees southeast of the faint star known as Theta Cassiopeiae. These meteors are best seen near 2100 (9pm) Local Standard Time (LST). Meteors from the December Phi Cassiopeiids strike the atmosphere at 17km/sec., which would produce meteors of very slow velocity. Expected rates would be near less than 1 no matter your location. It has been suggested that these meteors are a continuation of the Andromedids, but for now they remain separate.
This is the last opportunity for 2014 to view debris from comet 2P/Encke. Activity from the Northern Taurids (NTA) will soon end to be replaced by the artificial shower known as the Anthelions (more on that in 2 weeks). The Northern Taurids are active from a large radiant centered at 04:56 (074) +24. This position lies in north-central Taurus between the bright stars known as Aldebaran (Alpha Tauri) and El Nath (Beta Tauri). The radiant is best placed near midnight local standard time (LST), when it lies highest above the horizon. Meteors from the Northern Taurids strike the atmosphere at 27km/sec., which would produce meteors of slow velocity. Expected 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.
The November Orionids (NOO) are active from a radiant located at 06:08 (092) +15. This area of the sky is located in northeastern Orion, very close to the point occupied by the faint star known as Nu Orionis. The peak for this shower occurs on November 28th, so current rates should be near 3 shower members per hour, no matter your location. This is the most active source of meteors as seen from the northern hemisphere during this period. This location is close to the Northern Taurids , but far enough east to be distinguishable. The faster velocity of the November Orionids should help distinguish these meteors from the slower Taurids. The radiant is best placed for viewing near 0200 LST when it lies on the meridian and is highest above the horizon. With an entry velocity of 44 km/sec., the November Orionids would be of medium speed.
Geminid (GEM) activity begins this weekend from a radiant located near 06:36 (099) +34. This position lies on the Gemini/Auriga border, 3 degrees west of the fourth magnitude star known as Theta Geminorum. Expected rates this week would only be near one per hour as maximum is still 2 weeks away. Although Geminid meteors can be seen all night long, they are best seen near 0200 LST when the radiant lies highest above the horizon. This shower peaks on the night of December 12/13, when rates can surpass 60 shower members per hour in moonless skies. Unfortunately this year there will be a bright moon during the second half of the night and observers will be forced to look away from the moon to maintain their night vision. Geminid activity can be seen from the southern hemisphere but at much reduced rate. As seen from south of the equator, Geminid activity could only be seen for a few hours before and after 0200 LST. At 34 km/sec. the Geminids produce mostly meteors of medium velocity.
The Sigma Hydrids (HYD) are active from November 24 through December 21, with maximum activity occurring on December 6. The radiant is currently located at , which places it in eastern Canis Minor, 4 degrees southwest of the brilliant zero magnitude star known as Procyon (Alpha Canis Minoris). These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. Current rates should be near 1 per hour no matter your location. With an entry velocity of 61 km/sec., most activity from this radiant would be of swift speed.
The Puppid-Velids (PUP) are a vast complex of weak radiants located in the constellations of Puppis and Vela. Visual plots and photographic studies have revealed many radiants in this area during November and December. The combined strength of these radiants can produce a ZHR of ten. Actual hourly rates will be much less unless you happen to be observing from the deep Southern Hemisphere. Activity from this source begins around December 1st. The center of this activity is currently located at 08:32 (128) -47. This position lies in western Vela, two degrees west of the second magnitude star Gamma Velorum. Peak rates occur near December 7. These meteors are best seen near 0300 LST when the radiant lies highest above the horizon in a dark sky. Observers located in the Southern Hemisphere have an advantage viewing this shower as the radiant will rise higher into their sky allowing more activity to be seen. Since the radiant lies low in the south for most northern hemisphere observers, meteors seen from north of the equator tend to be long in length and long-lasting. At 42 km/sec. the Puppid-Velids produce meteors of average velocity.
The last of the Leonids (LEO) will be seen during this period from a radiant located at 10:48 (162) +17 . This position lies in central Leo, 5 degrees southeast of the second magnitude double star known as Algeiba (Gamma Leonis). The Leonid radiant is best placed during the last hour before morning twilight when the radiant lies highest in a dark sky. Leonids may be seen from the southern hemisphere but the viewing conditions are not quite as favorable as those north of the equator. Expect rates during this period of less than 1 shower member per hour no matter your location. With an entry velocity of 70 km/sec., most activity from this radiant would be of swift speed with numerous persistent trains on the brighter meteors.
The Psi Ursa Majorids (PSU) were discovered by observers in Japan using data from SonotaCo. This shower is active from December 1-16 with maximum activity occurring on December 5. At maximum the radiant is located at 11:16 (169) +44. This position lies in southern Ursa Major, one degree southeast of the third magnitude star known as Psi Ursae Majoris. This area of the sky is best placed during the last hour before dawn, when it lies highest above the horizon in a dark sky. Current rates would most likely be less than one per hour and may reach 1 per hour at maximum. Observers south of the equator would see rates less than 1 per hour due to the lower radiant elevation. At 61km/sec., the average Psi Ursa Majorid meteor would be swift.
The December Kappa Draconids (DKD) are another shower discovered in Japan by observers using data from SonotaCo. This short-lived shower is only active from December 2-6 with maximum activity occurring on December 3rd. On the night of maximum the radiant will be located at 12:22 (185) +70. This position lies in extreme western Draco, close to the faint star Kappa Draconis. While the radiant lies above the horizon all night for most of the northern hemisphere, it is best placed during the last hour before dawn, when it lies highest above the horizon in a dark sky. Rates could reach 3 per hour on the morning of the 3rd. Away from that morning I would expect hourly rates of less than 1. Due to the high northerly declination of the radiant these meteors are not visible from most of the southern hemisphere. At 41km/sec., the average December Kappa Draconid meteor would be of medium velocity.
The November Iota Draconids (NID) were discovered by Dr. Peter Brown during his 7 year meteoroid stream survey using the Canadian Meteor Orbit Radar. This source is active from November 11 through the 1st of December with maximum activity occurring on November 21st. The radiant is currently located at 13:08 (197) +65. This area of the sky lies in western Draco, close to the position occupied by a pair of faint stars known as 8 and 9 Draconis. The radiant is best placed during the last hour before morning twilight when the radiant lies highest in a dark sky. Expect rates of less than 1 per hour no matter your location. Due to the high northerly declination of the radiant these meteors are not visible from most of the southern hemisphere. Only southern equatorial regions would have any chance of seeing activity from this source. Meteors from the November Iota Draconids strike the atmosphere at 41km/sec., which would produce meteors of medium velocity.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately 12 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. Evening rates are reduced during this period due to moonlight.
The list below offers the information from above in tabular form. 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|
|Phoenicids (PHO)||Dec 02||00:32 (020) -27||10||20:00||? – ?||III|
|Dec. Phi Cassiopeiids (DPC)||Dec 05||01:33 (023) +53||19||21:00||<1 – <1||IV|
|Northern Taurids (NTA)||Nov 11||04:56 (074) +24||27||00:00||1 – <1||II|
|November Orionids (NOO)||Nov 29||06:08 (092) +15||44||01:00||3 – 3||II|
|Geminids (GEM)||Dec 13||06:36 (099) +34||34||02:00||1 – <1||I|
|Sigma Hydrids (HYD)||Dec 07||07:56 (119) +04||61||03:00||1 – 1||II|
|Puppid-Velids (PUP)||Dec 07||08:32 (128) -47||42||04:00||1 – 5||II|
|Leonids (LEO)||Nov 18||10:48 (162) +17||70||06:00||<1 – <1||I|
|Psi Ursa Majorids (PSU)||Dec 05||11:16 (169) +44||61||06:00||1 – <1||IV|
|Dec. Kappa Draconids (DKD)||Dec 03||12:22 (185) +70||41||07:00||1 – <1||IV|
|Nov. Iota Draconids (NID)||Nov 21||13:08 (197) +65||41||08:00||<1 – <1||IV|