Meteor Activity Outlook for February 20-26, 2010

February offers the meteor observer in the northern hemisphere a couple of weak
showers plus falling sporadic rates. This may not seem too exiting but you never
know when surprises are in store. An errant earthgrazer from the Centaurid complex
may shoot northward. Better yet, a bright fireball may light up the sky. February
is the start of the fireball season, when an abundance of fireballs seem to occur.
This lasts well into April and seems to occur mostly during the early evening hours.

Observers in the southern hemisphere are treated to the Alpha Centaurid peak on
the 8th plus the entire Centaurid complex of radiants is active all month long.
Sporadic rates are slightly less than those seen in January, but still stronger
than those witnessed north of the equator.

During this period the moon reaches its first
quarter phase on Monday February 22nd. At this time the moon lies ninety degrees
east of the sun and sets near midnight local standard time (LST). The estimated total
hourly rates for evening observers this week is near two for northern observers
and three for those viewing from south of the equator. For morning observers the
estimated total hourly rates should be near twelve from the northern hemisphere
and fifteen 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. Evening rates are reduced
due to moonlight.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning February 21/22. 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 11:00 (165) +05. This
area of the sky lies in a remote area of southwestern Leo. The nearest star that
is easily seen is fourth magnitude Sigma Leonis, located five degrees east of the
center of the radiant. 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 western Leo, Sextans, Crater, or western Virgo
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 last of the Alpha Centaurids (ACE) are visible this weekend.
This shower is only visible south of thirty degrees north latitude. The further
one is located south (down to 60S) the better the radiant is situated in the sky.
Expected rates from the southern hemisphere is now less than one per hour, even
with the radiant located high in the sky. The current radiant position lies at
15:03 (226) -63. This position lies in extreme southeastern Centaurus, five degrees
southeast of the brilliant zero magnitude star Rigel Kentaurus (Alpha Centauri).
The radiant is best placed during the last dark hour before dawn, when
it lies highest above the horizon in a dark sky. At 56km/sec. the Alpha Centaurids
would produce mostly swift meteors.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately
ten Sporadic meteors per hour during the last hour before dawn as seen
from rural observing sites. Evening rates would be near one per hour. As seen from
the mid-southern hemisphere (45S), morning rates would be near thirteen 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.
Evening rates are reduced due to moonlight.

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