Meteor Activity Outlook for May 31-June 6, 2008

June is another slow month for meteor activity.
There are no major showers active in June and only the Antihelion can be counted
on for continuous activity. Even the Antihelion is located so far south this time
of year that rates rarely exceed two per hour as seen from the northern hemisphere.
Sporadic rates reach their nadir in June 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 new
phase on Tuesday June 3rd. At this time the moon will be located near the sun
and will be invisible at night. As seen from the mid-northern hemisphere (45 N)
the estimated total hourly rates during the evening observers would be only one.
For morning observers the estimated total hourly rates should be near six. For
those located in the mid-southern hemisphere (45 S) morning rates would be near
fourteen and evening rates near three. 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.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning May 31/June 1. 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 large Antihelion (ANT) radiant is now centered at 17:36 (264) -23.
This area of the sky lies in southern Ophiuchus, three degrees northeast of the
third magnitude star Theta Ophiuchi. Actually any meteor from northern Scorpius,
western Sagittarius, as well as southern Serpens Cauda could be a candidate for
this shower. This radiant is best placed near 0200 LDT when it lies on the
meridian and is highest in the sky. Rates at this time should be near two for
northern observers and three for observers south of the equator. With an entry
velocity of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.

During late May and early June, an occasional long meteor may shoot upwards from
the northeastern horizon just before dawn. Most likely these are members of the
Daytime Arietid (DAR) meteor shower. The radiant lies approximately thirty
degrees west of the sun therefore only a trace of this shower can ever be seen by
the visual observer. Dawn becomes too bright before the radiant can achieve
sufficient altitude to provide a good display.

If this shower were visible in a dark sky it would be among the strongest displays
of the year. This shower is the strongest daylight/radio shower of the year. The
current position of the radiant is 02:40 (040) +20. This position lies in central
Aries, eight degrees southeast of the second magnitude star Hamal (Alpha Arietis).
Shower members would be visible only during the last hour before dawn with rates
at or less than one per hour. With an entry velocity of 37 km/sec., the average
Daytime Arietid meteor would be of medium speed.

As seen from the mid-northern hemisphere (45N) the Sporadic rates are
near their lowest rates of the year. One would expect to see approximately six
random meteors during the last hour before dawn from rural observing sites and
only one per hour during the evening hours. 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.

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