(meteorobs) Meteor Activity Outlook for August 8-14, 2009

Robert Lunsford lunro.imo.usa at cox.net
Fri Aug 7 17:00:44 EDT 2009


Meteor activity kicks into high gear in August as seen from the northern
hemisphere. The main reason for all this activity is the Perseid shower that
peaks on August 12. This shower is active most of the month and remains
above the level of the sporadic background for a week centered on August 12.
The sporadic activity is also increasing as seen from the northern
hemisphere and is now nearly double the rates from just three months ago. As
seen from south of the equator, meteor rates are still decent but falling
rapidly. The sporadic rates seen at the beginning of the month will be twice
as much as those seen during the last days of the month. The Perseid radiant
does not rise high into the sky as seen in the southern hemisphere so rates
from this shower are greatly reduced when compared to the northern
hemisphere.

During this period the moon reaches its last quarter phase on Thursday
August 13th. This weekend the bright moon will be present most of the night,
significantly reducing the meteor activity seen. As the week progresses the
moon will exit the evening sky but will still cause interference during the
prime morning hours. The estimated total hourly rates for evening observers
this week is near four no matter your location. For morning observers the
estimated total hourly rates should be near twenty no matter your location
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 August 8/9. 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 list below presents a summary of the expected activity this week. Rates
and positions are exact for Saturday night/Sunday morning August 8/9, but
may be used all week.

The full descriptions of each active meteor shower will continue next week
when the moon becomes less of a nuisance to observers.

Kappa Cygnids (KCG) 18:56 (284) +58 Velocity - 25km/sec.
Northern Hemisphere - 1 per hr. Southern Hemisphere - <1 per hr.

Alpha Capricornids (CAP) 21:08 (317) -06 Velocity - 23km/sec.
Northern Hemisphere - 1 per hr. Southern Hemisphere - 1 per hr.

Antihelion (ANT) - 21:56 (329) -10 Velocity - 30km/sec.
Northern Hemisphere - 1 per hr. Southern Hemisphere - 2 per hr.

Delta Aquariids (SDA) 23:16 (349) -13 Velocity - 41km/sec.
Northern Hemisphere - 1 per hr. Southern Hemisphere - 2 per hr.

Pisces Austrinids (PAU) 23:00 (345) -28 Velocity - 35km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Perseid (PER) 02:56 (044) +57 Velocity - 59km/sec.
Northern Hemisphere - 10 per hr. Southern Hemisphere - 5 per hr.

*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#X2009

Clear Skies!
Robert Lunsford
American 




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