(meteorobs) Meteor Activity Outlook for June 16-22, 2006

Robert Lunsford lunro.imo.usa at cox.net
Fri Jun 16 15:06:53 EDT 2006


During June observers in the northern hemisphere see some of their lowest
rates of the year. During this month the sporadic rates bottom out producing
an average of only one meteor every ten minutes, even from dark sky sites.
The active showers are also modest this month, barely adding any more
activity to the nighttime scene. Observers south of the equator are enjoying
some of their best rates of the year. This activity is produced from strong
sporadic rates and the fact that the Antihelion radiant is positioned well
south of the celestial equator this time of year. Combine this activity with
long nights and the core of the Milky Way riding high in the sky, and you
get an impressive scene. Unfortunately we have so few southern observers to
enjoy this scenario. This is a reason that observations from south of the
equator are so important.

The short nights in the northern hemisphere often make June the least active
month for meteor observers. Many of the worlds most active meteor observers
suffer from twilight all night long this time of year so those who live in
the more temperate latitudes should make every effort to view the elusive
June activity and to report their valuable data.

This week the moon will reach its last quarter phase on Sunday June 18th. On
this date the moon will rise near 0100 local daylight saving time and will
remain in the sky the remainder of the morning. Successful observing
sessions can be undertaken during this period as long as one keeps the moon
out your field of view. As the week progresses the waning crescent moon
rises later and later, thus viewing conditions improve with each passing
day. The estimated total hourly rates for evening observers this week is
near two for observers in the northern hemisphere and four for those south
of the equator. For morning observers the estimated total hourly rates
should be near eight for those in the northern hemisphere and fifteen for
those 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 moonlight.

The radiant positions listed below are exact for Saturday night/Sunday
morning June 17/18. 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. 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 June Lyrids (JLY) are active from June 10 through the 21st with maximum
activity near the 15th. 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 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.

The Antihelion (ANT) radiant is now centered at 18:36 (279) -23. This area
of the sky is located in western Sagittarius, three degrees northeast of the
third magnitude star Lambda Sagittarii. This radiant is best placed near
0200 local daylight time when it lies on the meridian and is highest in the
sky. Rates at this time should be near two per hour for those north of the
equator and three per hour south of the equator. With an entry velocity of
30 km/sec., the average Antihelion meteor would be of medium-slow speed.

After six months of declining rates the Sporadic rates for the Northern
Hemisphere are now finally starting to increase. One would expect to see
perhaps five random meteors during the last hour before dawn from rural
observing sites. During the first dark 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 four per
hour. Sporadic rates seen from the southern hemisphere are now increasing
toward a secondary maximum in July. One would see approximately twelve
random meteors per hour during the last hour before dawn and four per hour
during the first dark after the end of evening twilight. Rates near midnight
would be near eight per hour. Morning rates are reduced everywhere during
this period due to the glare from the moon.

June Lyrids (JLY)    18:32 (278) +45
Northern Hemisphere - 1/hr - Southern Hemisphere - >1

Antihelion (ANT)   18:36 (279) -23

Northern Hemisphere - 2/hr - Southern Hemisphere - 3/hr

*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#X2006

Clear Skies!
Robert Lunsford
American Meteor Society



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