(meteorobs) Meteor Activity Outlook for June 8-14, 2007

[Robert Lunsford]

June is a slow month for meteor activity, especially as seen from the
northern hemisphere. The June Lyrids peak mid-month but add little to the
overall activity. The June Bootids peak near months end but can be totally
absent. Sporadic rates as seen from the northern hemisphere are lowest this
month. From the southern hemisphere sporadic rates are quite strong with
much of this activity provided by unknown ecliptical radiants which ride
high in the sky this time of year as seen from south of the equator.

During this period the moon reaches its last quarter phase on Friday June 8.
At this time the half illuminated moon rises near 0100 local daylight time
and will remain in the sky the remainder of the morning. These circumstances
are less than perfect but the light of the half moon is much less that of a
full moon so successful meteor observations can be obtained during this
period. The estimated total hourly rates for evening observers this week is
near one for those located north of the equator and three for observers
south of the equator. For morning observers the estimated total hourly rates
should be near six for those located in the northern hemisphere and fourteen
for those viewing from south of the equator. 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. Morning rates are reduced due to the bright moon.

The radiant positions listed below are exact for Saturday night/Sunday
morning June 9/10. 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. Doing this 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 Antihelion (ANT) radiant is now centered at 18:08 (272) -23. This area
of the sky is centered in western Sagittarius, four degrees northwest of the
third magnitude star Lambda Sagittarii. 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 one per hour as seen in the northern hemisphere and
two per hour for those located south of the equator. With an entry velocity
of 30 km/sec., the average antihelion meteor would be of medium-slow speed.

The June Lyrids (JLY) are active from June 10 through the 21st with maximum
activity near the 16th. The radiant has a published position of 18:32 (278)
+35 but most of the recent activity has occurred from an area further north
toward Draco (Xi Draconids). Analysis of recent video results indicate a
sharp radiant near 18:32 (278) +45 so we suggest you use this position on
June 16 for classifying these meteors. This position lies in northern Lyra,
six degrees north of the zero magnitude star Vega (Alpha Lyrae). This
radiant culminates near 0200 local daylight saving time. Due to the high
northern position these meteors are best seen from the northern hemisphere.
With an entry velocity near 40 km/sec., the average June Lyrid meteor would
be of medium-fast speed.

Sporadic rates are bottoming out for observers in the northern hemisphere
and slightly rising for those located south of the equator. One would expect
to see perhaps five random meteors during the last hour before dawn from
rural observing sites located in the northern hemisphere. During the first
dark hour after the end of evening twilight, perhaps two random meteors can
be seen per hour. Sporadic rates increase as the night progresses so rates
seen near midnight would be near three per hour. Late morning sporadic rates
seen from the southern hemisphere are now near twelve per hour from rural
observing sites. During the first dark hour after the end of evening
twilight, perhaps three random meteors can be seen per hour, increasing to
six by midnight. Morning rates are reduced due to the bright moon.

Antihelion (ANT) - 18:08 (272) -23
Northern Hemisphere - 1   Southern Hemisphere - 2

June Lyrids (JLY)  18:08 (272) +45
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#X2007

Clear Skies!
Robert Lunsford
American Meteor Society