Meteor Activity Outlook for August 14-20, 2010

Meteor activity kicks into high gear in August
as seen from the northern hemisphere. The main reason for this activity surge is
the Perseid shower that peaks on August 13. This shower is active most of the
month and remains above the level of the sporadic background for a week centered
on August 13. 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 high 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 first
quarter phase on Monday August 16th. At this time the moon will be located ninety
degrees east of the sun and will set near 0100 local daylight time (LDT) for
locations in the mid-northern latitudes of the northern hemisphere. This weekend
the waxing crescent moon will set a bit just prior to midnight for the locations
mentioned above, and will be gone from the sky during the active morning hours.
The estimated total hourly rates for
evening observers this week is near three no matter your location. For morning
observers the estimated total hourly rates should be near thirty-five from the
northern hemisphere and twenty 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 slightly reduced this week due to moonlight.

The radiant (the area of the sky where meteors appear
to shoot from) positions and rates listed below are exact for Saturday night/Sunday
morning August 14/15. 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:

Activity from the August Draconids (AUD) are currently active
from a radiant located at 18:14 (273) +62. This position lies in southern Draco,
ten degrees north of the second magnitude star Eltanin (Gamma Draconis). Maximum
activity is not predicted until August 21st so current rates would be low, less
than one per hour. With an entry velocity of 23 km/sec. most of these meteors will
appear to move slowly. The radiant is best placed near 2200 Local Daylight Time
(10pm LDT) when it lies highest in the sky. Due to its high northern declination
this shower is not well seen from the southern hemisphere.

The Kappa Cygnids (KCG) are active from a wide radiant located at 19:06 (287) +52.
This position is further south than previous publications. It has been
updated through the use of video observations by the International Meteor Organization.
The new location lies on the Cygnus/Draco border, three degrees southwest of the
faint star Kappa Cygni. Maximum activity occurred on August 14th so current rates
would be near two per hour from the northern hemisphere and
less than one shower member per hour from south of the equator. With an entry
velocity of 23 km/sec. most of these meteors will appear to travel slower than
average. The radiant is best placed near 2300 LDT (11pm LDT) when it lies nearly
overhead for much of the Northern Hemisphere. Due to its high northern declination
this activity is not well seen from the southern hemisphere.

The wide Antihelion (ANT) radiant is now centered at 22:20 (335) -08. This
area of the sky lies in central Aquarius, three degrees southeast of the fourth
magnitude star Theta Aquarii. This radiant is best placed near 0200 LDT 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 northern Piscis Austrinus, Capricornus, Aquarius,
or southern Pegasus 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 Delta Aquariids (SDA) reached maximum activity on July 30th.
The shower is still active from a radiant located at 23:36 (354) -12. This position
lies in eastern Aquarius, three degrees northwest of the fourth magnitude star Omega 2
Aquarii. The radiant is best placed near 0300 LDT, when it lies highest in the sky.
With an entry velocity of 42 km/sec., most activity from this radiant would be of
average velocities. Expect rates of less than one per hour north of the equator and
one per hour from the southern hemisphere.

Another new shower discovered by Sirko Molau and Juergen Rendtel from the IMO’s
video database are the Eridanids (ERI). This shower is active from August
4th through the 18th with maximum activity occurring on the 9th. Hourly rates could
reach near two per hour at maximum. This shower was observed by me during the Perseid
maximum last week. The radiant is currently located at 03:12 (048) -09. This area of
the sky is located in western Eridanus, three degrees east of the faint star Eta
Eridani. This radiant is best placed during the last hour before
dawn when it lies highest in a dark sky. Hourly rates are expected to be less than
one. With an entry velocity of 64 km/sec., the average Eridanid meteor would be swift.

The Perseids (PER) reached maximum activity on Friday August 13th with zenith
hourly rates (ZHR’s) near 90. They are still active from a radiant located at
03:24 (051) +58. This position actually lies in southern Camelopardalis, eight
degrees north of the second magnitude star Mirfak (Alpha Persei). The radiant is
best placed during the last hour before the start of
morning twilight when it lies highest in a dark sky. Current rates would be near
twenty per hour, falling to less than ten by the end of the week. Activity from the
Perseids is not well seen south south of the equator and completely invisible south
of 40 degrees south latitude. With an entry velocity
of 61 km/sec., most activity from this radiant would be swift.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately
thirteen sporadic meteors per hour during the last hour before dawn as seen from
rural observing sites. Evening rates would be near two per hour. As seen from the
mid-southern hemisphere (45S), morning rates would be near nine 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. Rates
are slightly reduced during the evening hours 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.