Meteor Activity Outlook for November 3-9, 2012
November 4, 2012
The following is a slightly edited version of Bob Lunsford’s excellent weekly summary of meteor activity. The original version can be found at the American Meteor Society’s site.
As seen from the northern hemisphere, meteor rates continue to be strong in November. While no major activity is expected this month, the two Taurid radiants plus the Leonids keep the skies active. The addition of strong sporadic rates make November one of the better months to view meteor activity from north of the equator. Skies are fairly quiet as seen from the
southern hemisphere this month. Activity from the three showers mentioned above may be seen from south of the equator, but the sporadic rates are much lower than those seen in the northern hemisphere.
During this period the moon reaches its last quarter phase on Wednesday November 7th. At this time the moon is located ninety degrees west of the sun and well rise near 2300 (11pm) local standard time (LST). This weekend the waning gibbous moon will rise during the late evening hours and will interfere with meteor observing the remainder of the night. As the week progresses the moon will rise later and later, becoming less of a nuisance with each passing night. The estimated total hourly meteor rates for evening observers this week is near four for observers located at mid-northern latitudes and three for observers in mid-southern latitudes. For morning observers the estimated total hourly rates should be near fourteen from the mid-northern hemisphere and eight from the mid-southern hemisphere. 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. Rates during the morning hours are reduced this week due to moonlight.
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 3/4. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.
The following radiants are expected to be active this week:
Remnants from the famous Andromedid (AND) shower, noted for intense storms during the 19th century, may still be seen throughout November. The current position of this large radiant is 01:24 (021) +23 . This position lies in eastern Pisces, ten degrees west of the second magnitude star Hamal (Alpha Arietis). The radiant is so diffuse that Andromedid meteors may be seen coming from southern Andromeda, Triangulum, and northwestern Aries as well as eastern Pisces. Visual activity is expected to be low, but detectable. An inconspicuous maximum occurs on November 9, when this source is the 5th most active radiant in the sky. The Andromedid meteors are best seen near 2200 LST, when the radiant lies on the meridian and lies highest in the sky. At 19km/sec., the average Andromedid will appear as a very slow moving meteor.
The Northern Taurids (NTA) are now active from a large radiant centered at 03:28 (052) +21. This area of the sky lies on the Aries/Taurus border, five degrees southwest of the famous naked eye open cluster known as the Pleiades or the Seven Sisters. The radiant is best placed near 0100 LST, when it lies highest above the horizon. Maximum activity is not expected until November 13, so current rates would be 2-3 per hour, no matter your location. Meteors from the Northern Taurids strike the atmosphere at 29km/sec., which would produce meteors of slow velocity. You must face in the general direction of the north and south Taurid radiants in order to tell them apart.
The Southern Taurid (STA) radiant is currently located at 03:36 (054) +13. This position lies in western Taurus, ten degrees south of the famous naked eye open cluster known as the Pleiades or the Seven Sisters. This radiant is best placed near 0100 LST, when it lies on the meridian and is located highest in the sky. Maximum occurred on October 9th, so rates would now be near one per hour when the radiant lies high in the sky. With an entry velocity of 29 km/sec., the average Southern Taurid meteor would be of slow velocity.
The Orionids (ORI) are still the second most active shower this upcoming week producing up to two shower members per hour from a radiant located at 07:04 (106) +16. This area of the sky is located in southern Gemini, five degrees east of the second magnitude star Alhena (Gamma Geminorum). The radiant is best placed for viewing near 0400 LST when it lies on the meridian and is highest above the horizon. Orionid meteors are equally well seen either side of the equator. With an entry velocity of 67 km/sec., most activity from this radiant would be swift.
The Leonids (LEO) are actually active in small numbers during the morning hours in early November. The radiant is currently located at 09:36 (144) +28. This position lies in northwestern Leo, four degrees northwest of the fourth magnitude star Mu Leonis. Rates are only one per hour at best but will increase as the moon exits the morning sky. 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.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately seven 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 three 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. Rates during the morning hours are reduced this week due to moonlight.
The list below presents a summary of the expected activity this week. Rates and
positions are exact for Saturday night/Sunday morning, but may be used all week.
Andromedids (AND) – 01:24 (021) +23 Velocity 19km/sec
Northern Hemisphere – 1 per hr Southern Hemisphere – <1 per hour
Northern Taurids (NTA) – 03:28 (052) +21 Velocity 29km/sec
Northern Hemisphere – 3 per hr Southern Hemisphere – 2 per hour
Southern Taurids (STA) – 03:36 (054) +13 Velocity 29km/sec
Northern Hemisphere – 1 per hr Southern Hemisphere – 1 per hour
Orionids (ORI) 07:04 (106) +16 Velocity 67km/sec
Northern Hemisphere – 2 per hr Southern Hemisphere – 2 per hour
Leonids (LEO) 09:36 (144) +28 Velocity 71km/sec
Northern Hemisphere – <1 per hr Southern Hemisphere – <1 per hour
American Meteor Society