(meteorobs) Meteor Activity Outlook for June 24-30, 2005

Robert Lunsford lunro.imo.usa at cox.net
Fri Jun 24 10:26:27 EDT 2005


The moon reaches its last quarter phase on Tuesday June 28. This weekend and
for the remainder of this period, the moon will be present in the early
morning sky, limiting the meteor activity to be seen. The sources of meteors
listed below are active during this period but will be difficult to observe.
If your sky is transparent and the limiting magnitude exceeds +5.0, then you
may be able to achieve some success at observing during this period. The
estimated total hourly rates for evening observers this week is near two for
those in the Northern Hemisphere and three for those located in the Southern
Hemisphere. For morning observers the estimated total hourly rates should be
near four for those located in the Northern Hemisphere and six for those in
the Southern Hemisphere. 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.
Rates are reduced this week due to intense moonlight.

The positions listed below are exact for Saturday night/Sunday morning June
25/26. The positions do not change greatly day to day so these positions may
be used during this entire period. Most star atlases (available at science
stores and libraries) 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
location. Meteor activity is not seen from radiants that are located below
the horizon. The radiants below are listed in a west to east manner in order
of right ascension (celestial longitude). The radiants listed first are
located further west therefore are accessible earlier in the night while
those listed last rise later in the night. This list also provides the order
of ascending velocity for each radiant with those listed first usually being
much slower than those last on the list. Velocity should not be the prime
factor for shower association as all showers can produce slow meteors. Slow
meteors can be produced from normally swift showers, such as the Leonids,
when meteors appear near the radiant or close to the horizon. The true
velocity is only revealed in shower members seen far from the radiant and
high in the sky.

The detailed descriptions of each shower will return next week when
moonlight becomes less of a factor.

Special note on the June Bootids (JBO): The short-lived June Bootids are
expected to peak near 0800 Universal Time on June 27 (the evening of the
26th for the Eastern Pacific areas). This is favorable timing for the
Eastern Pacific areas such as Hawaii. No outburst is expected and only a
limited amount of activity is predicted. Observations, either positive or
negative, are important so observers are urged to view at this time. There
will be a small window of opportunity between the end of evening twilight
(if far enough south) and moonrise when the sky will be dark and useful for
viewing. This radiant is not favorably placed for observers in the Southern
Hemisphere. On the 27th, the radiant lies fifteen degrees east of the second
magnitude star Alkaid (Eta Ursae Majoris).  Any JBO activity would be
extremely slow.

June Bootids (JBO)        14:56  (224)  +48
Hourly Rate =    Var.  N.  Hemisphere,   0  S. Hemisphere

Anthelion  (Sagittarids)    18:16 (289) -22
Hourly Rate =     1   N. Hemisphere,    2  S. Hemisphere

Clear Skies!
Robert Lunsford
American Meteor Society
http://www.amsmeteors.org/lunsford/



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