(meteorobs) Meteor Activity Outlook for May 17-23, 2008

[Robert Lunsford]

May is a fairly slow month for meteor activity. The Eta Aquariids are very
active the first week 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 2-3 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 Tuesday May 20. At
this time the moon will be in the sky all night long. The intense moonlight
will obscure all but the brightest meteors making observations difficult.
The estimated total hourly rates for evening observers this week is near one
for those located in the mid-northern hemisphere (45 N) and two for those
viewing from the mid-southern hemisphere (45 S). For morning observers the
estimated total hourly rates should be near five for those located in the
mid-northern hemisphere (45 N) and ten 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. Rates are reduced this week due to intense moonlight.

The radiant positions and rates listed below are exact for Saturday
night/Sunday morning May 17/18. 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 condensed version of the expected activity this
week. Rates and positions are exact for Saturday night/Sunday morning.

Antihelion (ANT) - 16:40 (250) -22   Velocity - 30km/Sec.
Northern Hemisphere - 1   Southern Hemisphere - 2

Eta Aquariid (ETA)  23:08 (347) +04   Velocity - 66km/Sec.
Northern Hemisphere - 1   Southern Hemisphere - 1

*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#X2008

Clear Skies!
Robert Lunsford
American Meteor Society