(meteorobs) Meteor Activity Outlook for November 26-December 2, 2011

[Robert Lunsford]

During this period the moon reaches its first quarter phase on Friday December 2nd. At that time the moon will lie ninety degrees east of the sun and will set near midnight local standard time (LST) for observers situated at mid-northern latitudes. This weekend the waxing crescent moon will set during the evening hours and will not interfere with the good activity present during the morning hours. The estimated total hourly rates for evening observers this week is near four as seen from the northern hemisphere and three as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near twenty as seen from mid-northern latitudes and fourteen from mid-southern latitudes. 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.

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 26/27. 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 showers 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 by this shower occurred in 1956 when ZHR's were near 100. Peak activity occurs on December 6. Little activity is expected away from the peak night. The radiant is currently located at 00:46 (011) -52. This position lies in central Phoenix some ten degrees southeast of the second magnitude star Ankaa (Alpha Phoenicis). These meteors are best seen near 2000 (8pm) LST, when the radiant lies highest above
the horizon in a dark sky. Due to the southerly declination of the radiant, this shower is not visible north of the northern tropical areas. The deep southern hemisphere has the best chance of seeing any activity. At 22 km/sec. the Phoenicids produce very slow meteors.

The last of the famous Andromedid (AND) shower, noted for intense storms during the 19th century, will be still be seen this week. The current position of this large radiant is 01:43 (026) +45. This position lies in northeastern Andromeda, five degrees northwest of the famous second magnitude double star known as Almach (Gamma Andromedae). The radiant is so diffuse that Andromedid meteors may also be seen coming from Triangulum, extreme northwestern Perseus, and southern Cassiopeia as well as Andromeda. Visual activity is expected to be low, but detectable. An inconspicuous maximum occurred on November 12. The Andromedid meteors are best seen near 2100 (9pm) LST, when the radiant lies on the meridian. At 19km/sec., the average Andromedid will appear as a very slow moving meteor.

The Northern Taurids (NTA) are active from a large radiant centered at 04:46 (072) +25. This position lies in northern Taurus, two degrees north of the fourth magnitude star Tau Tauri. The radiant is best placed near midnight LST, when it lies highest above the horizon. Since the radiant is large, Northern Taurid meteors may also appear to come from southwestern Auriga, southeastern Perseus, northwestern Orion, as well as Taurus. Meteors from the Northern Taurids strike the atmosphere at 29km/sec., which would produce meteors of slow velocity. Expected rates would be near two per hour, no matter your location.

The November Orionids (NOO) were recently discovered by Sirko Molau and Jueregen Rendtel by analyzing video data from the IMO network. For years this radiant was lost in the maze of radiants active this time of year. Due to the low activity, visual observers were unable to detect this shower. This shower is active from November 18 through December 9. Maximum activity occurs on November 30. Once you know the radiant in advance, this shower is actually quite noticeable, producing an average of two shower members per hour near maximum. The radiant is currently located at 05:56 (089) +15. This position lies in northeastern Orion, seven degrees north of the orange first magnitude star Betelgeuse (Alpha Orionis). These meteors are best seen near 0100 LST when the radiant lies on the meridian and highest above the horizon. At 44 km/sec. the November Orionids produce mostly medium velocity meteors.

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. On that date the center of this activity is located at 07:58 (119) -45. This position lies in eastern Puppis, five degrees northwest 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. At 40 km/sec. the Puppid-Velids produce meteors of average velocity.

Another shower verified by video means are the Psi Ursa Majorids (PSU). This shower is active from November 29-December 13 with maximum activity occurring on December 5. On Tuesday the radiant is located at 10:38 (159) +45. This position lies in southwestern Ursa Major, five degrees west of the third magnitude star Kappa 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. At 61km/sec., the average Psi Ursa Majorid meteor would be swift.

This week is your last chance to see the Leonids (LEO) for 2011. This shower peaked near November 18 and current rates are well below one per hour no matter your location. The radiant is located at 10:41 (160) +19. This position lies in central Leo, four degrees east of the second magnitude star Algeiba (Gamma Leonis). The area of the sky does not clear the eastern horizon until the late evening hours so no Leonid activity can be seen during the early evening hours. These meteors are best seen during the last hour before the onset of morning twilight, when the radiant lies highest above the horizon in a dark sky. At 71km/sec., the average Leonid is swift with a high percentage of trains.

Another shower verified by video means are the December Kappa Draconids (KDR). This shower is active from November 30-December 6 with maximum activity occurring on December 3rd. Activity from this source is not expected this weekend. On the night of maximum the radiant will be located at 12:22 (185) +72. This position lies in extreme western Draco, two degrees northwest of 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. Current rates would most likely be less than one per hour. At 43km/sec., the average December Kappa
Draconid meteor would be of medium velocity.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately twelve sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near three per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near six per hour as seen from rural observing sites and two per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.

The list below presents a condensed version of the expected activity this week.
Rates and positions are exact for Saturday night/Sunday morning but may be used
for the entire period.

December Phoenicids (PHO) - 00:46 (011) -52   Velocity - 22km/sec.
Northern Hemisphere - <1 per hr.   Southern Hemisphere - <1 per hr.

Andromedids (AND) - 01:43 (026) +45   Velocity - 19km/sec.
Northern Hemisphere - <1 per hr.   Southern Hemisphere - <1 per hr.

Northern Taurids (NTA) - 04:46 (072) +25   Velocity - 29km/sec.
Northern Hemisphere - 2 per hr.   Southern Hemisphere - 2 per hr.

November Orionids (NOO) - 05:56 (089) +15   Velocity - 44km/sec.
Northern Hemisphere - 2 per hr.   Southern Hemisphere - 2 per hr.

Puppid-Velids (PUP)  - 07:58 (119) -45   Velocity - 40km/sec.
Northern Hemisphere - <1 per hr.   Southern Hemisphere - <1 per hr.

Psi Ursa Majorids (PSU)   - 10:38 (159) +45   Velocity - 61km/sec.
Northern Hemisphere  -<1 per hr.   Southern Hemisphere - <1 per hr.

Leonids (LEO) - 10:41 (160) +19    Velocity - 71km/sec.
Northern Hemisphere  -<1 per hr.   Southern Hemisphere - <1 per hr.

December Kappa Draconids (KDR)   - 12:22 (185) +72   Velocity - 43km/sec.
Northern Hemisphere -<1 per hr.   Southern Hemisphere - <1 per hr.

Clear Skies!
Robert Lunsford
American Meteor Society