Meteor Activity Outlook for May 9-15, 2009

May is a fairly slow month for meteor activity.
The Eta Aquariids are very active the first two weeks of the month then fade as
the month progresses. The only other showers active this month are the Eta Lyrids
and the Antihelion radiant. These will add only 1-2 meteors per hour to the total
count. Sporadic rates are low but steady as seen from the mid-northern hemisphere
(45 N). Sporadic rates seen from the mid-southern hemisphere (45 S) continue
to rise this month toward a maximum in July.

During this period the moon reaches its full
phase on Saturday May 9th. At this time the moon will be present in the sky all night
long, making meteor observing difficult at best. Later in the period a window of
opportunity for viewing in dark skies will exist during the evening hours between
the end of evening twilight and moonrise. Unfortunately rates would still be very
low during this time. The estimated total hourly rates for evening observers this week is near
one as seen from the northern hemisphere and two for those situated south of the
equator. For morning observers the estimated total hourly rates should be near
three for those located in the mid-northern hemisphere (45 N) and seven 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. Rates this week are reduced due to the intense moonlight.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning May 9/10. 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 full descriptions of each active meteor shower will continue next week when
the moon becomes less of a nuisance to observers.

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.