Meteor Activity Outlook for February 15-21, 2008

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 2-3 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 its full
phase on Thursday February 21st. At this time the moon will be located opposite
the sun and will be in the sky all night long. During this upcoming weekend the
waxing gibbous moon will set early during the morning hours and will allow for a
few hours of dark sky viewing before the onset of dawn. The estimated total hourly rates for evening
observers this week is near two no matter your location. For morning observers the
estimated total hourly rates should be near twelve for those located in the
mid-northern hemisphere (45 N) and fifteen for those viewing from the mid-southern
hemisphere (45 S). 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. Evening rates are reduced due to the
bright moonlight.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning February 16/17. 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 10:44 (161) +06. This
area of the sky lies in southern Leo, ten degrees southeast of the bright star
Regulus (alpha Leonis). This radiant is best placed near 0100 local standard
time when it lies on the meridian and is highest in the sky. Actually any meteor
from northern Sextans or southern Leo could be a candidate for this shower. Rates at
this time should be near two per hour as seen from the northern hemisphere and one
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.

The Delta Leonids (DLE) reach a ZHR of one on February 15. Visual rates
will be less than one at this time. The radiant is now located at 10:48 (162) +19.
This area of the sky lies in central Leo, ten degrees northeast of the bright star
Regulus (alpha 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 medium-slow speed.

The Alpha Centaurids (ACE) are active from a radiant located at 14:48 (222)
-62. This area of the sky is located in southeastern Centaurus, just south of the
brilliant star Rigel Kentaurus (alpha Centauri). Current rates would be
near one shower member 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.

Sporadic rates are now slowly falling no matter your location. One would
expect to see approximately ten random meteors during the last hour before dawn
from rural observing sites in the northern hemisphere and thirteen from the southern
hemisphere. During the first dark hour after the end of evening twilight, perhaps
two random meteors can be seen per hour, no matter your location.

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