Meteor Activity Outlook for October 15-21, 2011

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.

Meteor activity in general increases in October when compared to September. A major shower (the Orionids) is active most of the month along with many minor showers. Both branches of the Taurids become more active as the month progresses, providing slow, graceful meteors to the nighttime scene. The Orionids are the big story of the month reaching maximum activity on the 22nd. This display can be seen equally well from both hemispheres which definitely helps out observers located in the sporadic-poor southern hemisphere this time of year.

During this period the moon reaches its last quarter phase on Thursday October 20th. At this time the moon will lie ninety degrees west of the sun and will rise near midnight local daylight time (LDT). This weekend the waning gibbous moon will rise during the early evening hours and will effectively ruin the late evening and early morning hours with intense moonlight. One could watch for meteors during the early evening hours between dusk and moonrise. Unfortunately at this time of night activity will be low. The estimated total hourly rates for evening observers this week is near two as seen from the northern hemisphere and one as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near eight as seen from mid-northern latitudes and six 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. Rates are reduced during this period due to the intense 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 October 15/16. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

Detailed descriptions of each shower will continue when the moonlight situation improves.The following showers are expected to be active this week:

Rates and positions are exact for Saturday night/Sunday morning.

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

Shower Name                 RA     DEC   Vel     Rates
                                         km/s   NH    SH
STA Southern Taurids      02h 27m  +10    27     1     1 
SSA Sigma Arietids        03h 10m  +22    46    <1    <1
ZTA Zeta Taurids          05h 19m  +12    67    <1    <1
ORI Orionids              06h 06m  +16    61     2     2
OCU October Ursa Majorids 09h 42m  +63    53    <1    <1

RA - Right Ascension
DEC - Declination
Vel - Velocity relative to Earth (in km per sec)
Rates - Rate of visible meteors per hour from a dark site
NH - Northern Hemisphere
SH - Southern Hemisphere

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