Meteor Activity Outlook for January 23-29, 2010

The Meteor Activity Outlook is a weekly summary of expected meteor activity written by Robert Lunsford, Operations Manager of the American Meteor Society and contributor to this blog. The original unedited version of this week’s Meteor Activity Outlook can be found at the American Meteor Society’s site.

January sees a peak of sporadic activity for the southern hemisphere while rates seen north of the equator begin a steady downward turn that continues throughout the first half of the year. The sporadic activity is good for both hemispheres, but not as good as it was for northern observers in December. Once the Quadrantids have passed the shower activity for January is very quiet.

During this period the moon reaches its first quarter phase on Saturday January 23rd. At this time the moon will be limited to the evening hours and will set near midnight local standard time (LST). As the week progresses the moon begins to interfere into the active morning hours as it sets later and later with each passing night. Toward the end of the period the nearly full moon will be in the sky nearly all night long. This will make observations difficult at best. The estimated total hourly rates for evening observers this week is ~3 no matter your location. For morning observers the estimated total hourly rates should be ~15 from the northern hemisphere and ~16 as seen from the 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 are reduced this week due to moonlight.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning January 23/24. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

The following showers are expected to be active this week.

Antihelion (ANT)

The wide Antihelion (ANT) radiant is now centered at 09:08 (137) +15. This area of the sky lies in eastern Cancer. The bright orange planet Mars, now near opposition, lies to northwest of this position. This radiant is best placed near 0100 LST when it lies on the meridian and is located highest in the sky. Due to the large size of this
radiant, any meteor radiating from northwest Hydra, western Leo, or Cancer could be a candidate for this shower. Rates at this time should be ~2 per hour as seen from the northern hemisphere and ~1 per hour for observers located south of the equator. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.

December Leonis Minorids (DLM)

The December Leonis Minorids (DLM) are near the end of their activity period. A few stragglers from this radiant may still be seen from a radiant located at 12:46 (192) +15. This position lies in southern Coma Berenices. The nearest star of note would be third magnitude Epsilon Virginis, located five degrees to the southeast. These meteors are best seen near 0500 LST when the radiant lies highest above the horizon. This shower peaked on December 20th so current rates would be near < 1 per hour no matter your location. At 64km/sec. the December Leonis Minorids produce mostly swift meteors.

The table 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 all week long.

Shower Name                RA     DEC   Vel     Rates
                                        km/s   NH    SH
ANT Antihelions          09h 08m  +15    30     2     1
DLE Dec Leonis Minorids  12h 46m  +15    64    <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