Meteor Activity Outlook for February 14-20, 2009

February is the only month of the year that sees
a fall in rates in both hemispheres. As seen from the northern hemisphere,
sporadic rates continue the fall that began in January. This will continue until
June when rates reach their nadir. After a brief peak of activity in January,
sporadic rates in the southern hemisphere also slide downward until March. Shower
activity is low this month but decidedly more interesting in the southern
hemisphere. During February there are several sources of activity in the southern
morning sky. Most notable is the Alpha Centaurids, which are active during
the entire month of February. Other sources are scattered from Carina
through Puppis, Vela, and on into Centaurus and Lupus. None of these even
rate as a minor shower but together, along with the Alpha Centaurids, create
some interesting viewing during the summer nights south of the equator. Only
a trace of this activity can be seen from the northern tropics. The
Antihelion radiant remains north of the celestial equator and produces a
modest 1-2 meteors per hour from Leo. The weak Delta Leonids become active
at mid-month but are few and far between, even at maximum activity.

During this period the moon reaches it last
quarter phase on Monday February 16th. At this time the moon lies ninety degrees
west of the sun and will set rise midnight local standard time (LST). These lunar
conditions are favorable for the slow evening hours. As the week progresses the
moon wanes and rises later each morning, creating an improving situation for the
morning observer. The estimated total hourly rates for evening
observers this week is near three as seen from the northern hemisphere and four
for those situated south of the equator. For morning observers the estimated total
hourly rates should be near ten for those located in the mid-northern
hemisphere (45 N) and twelve for those viewing from the mid-southern hemisphere
(45 S). Locations between these two extremes would see activity between the listed
figures. These rates assume that you are watching from rural areas away from all
sources of light pollution. 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. Morning rates are reduced due to moonlight.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning February 14/15. 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 wide Antihelion (ANT) radiant is now centered at 10:36 (159) +07. This
area of the sky lies in southern Leo, seven degrees southeast of the first magnitude
Regulus (Alpha Leonis). 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 southern Leo or Sextans could be a
candidate for this shower. Rates at this time should be near two per hour no
matter your location. With an entry velocity of 30 km/sec., the average Antihelion
meteor would be of medium-slow speed.

The Delta Leonids (DLE) reach a ZHR of one on February 15. Visual rates
will be less than one at this time, no matter your location. The radiant is now
located at 10:36 (159)+19. This area of the sky lies in central Leo, two degrees
east of the second magnitude star Algeiba (Gamma Leonis). This radiant is best
placed near 0100 local standard time when it lies on the meridian and is highest
in the sky. With an entry velocity of 23 km/sec., the average Delta Leonid meteor
would be of slow speed.

The Alpha Centaurids (ACE) are active from a radiant located at 14:40
(220) -62. This area of the sky is located in southeastern Centaurus, just south
of the brilliant zero magnitude star Rigel Kentaurus (Alpha Centauri). As seen
from the southern hemisphere, current rates would be 1-2 per hour. These meteors
are best seen near 0500 local standard time when the radiant lies highest above
the horizon. This shower is not visible north of 28 degrees north latitude and
also poorly seen in the northern tropics. The southern hemisphere offers a much
better view of this activity as the radiant lies much higher in the southern
sky. Those located at high southern latitudes will actually encounter
morning twilight before the radiant reaches culmination. At 56 km/sec. the
Alpha Centaurids will usually produce meteors of swift velocity.

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 two per hour. As seen from
the mid-southern hemisphere (45S), morning rates would be near eight per hour as
seen from rural observing sites and three per hour during the evening hours. Locations
between these two extremes would see activity between the listed figures. Morning
rates are reduced due to moonlight.

The table 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.