Meteor Activity Outlook for June 4-10, 2011

During this period the moon reaches its first quarter phase on Thursday June
9th. At this time the moon will lie ninety degrees east of the sun and will set
near 0100 local daylight time (LDT). This weekend the waxing crescent moon will
not cause any problems viewing meteor activity as it is very thin and sets
during the evening hours. The estimated total hourly rates for evening observers
this week is near three as seen from the northern hemisphere and four as seen
from the southern hemisphere. For morning observers the estimated total hourly
rates should be near eight from the northern hemisphere and eighteen as seen
from south of the equator. 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.

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 June 4/5. 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 17:48 (267) -23. This area
of the sky lies in western Sagittarius, five degrees east of the third magnitude
star Theta Ophiuchi. 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 southern Ophiuchus, western Sagittarius,
Serpens Cauda, or Scorpius could be a candidate for this shower. Rates at this
time should be near two per hour as seen from the northern hemisphere and three
per hour as seen from south of the equator. With an entry velocity of 30
km/sec., the average Antihelion meteor would be of medium-slow speed.

While not included on most meteor shower lists, this week would be the best time
to try and view activity from the Arietid (DAR) meteor shower. This shower has a
radiant located only 32 degrees west of the sun. Activity can only be seen
during the last hour before dawn, when the radiant clears the northeastern
horizon. The Arietids reach maximum activity on June 8 from a radiant located at
02:56 (044) +24. This position lies in eastern Aries, twelve degrees east of the
second magnitude star Hamal (Alpha Arietis). Visual rates will be low but any
activity seen will be long earthgrazers. With an entry velocity of 37km/sec.,
these meteors would be of medium velocity. If this shower was visible at night
with the radiant high in the sky, it would produce nearly 60 meteors per hour at
maximum activity. This shower is the strongest source of annual radio meteor
activity.

As seen from the mid-northern hemisphere (45N) one would expect to see
approximately six 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 fifteen
per hour as seen from rural observing sites and three per hour during the
evening hours. Locations between these two extremes would see activity between
the listed figures.

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