(meteorobs) Meteor Activity Outlook for June 12-18, 2010
Robert Lunsford
lunro.imo.usa at cox.net
Thu Jun 10 11:16:56 EDT 2010
June is another slow month for meteor activity. There are no major showers active in June and only the Antihelion source 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 Saturday June 12th. At this time the moon will rise and set with the sun and
will not be visible at night. Next week the waxing crescent moon will enter the evening sky but will set long before the more active
morning hours arrive. The estimated total hourly rates for evening observers this week is near three for northern observers and four
for those viewing from south of the equator. For morning observers the estimated total hourly rates should be near seven from the
northern hemisphere and eighteen as seen from the southern hemisphere. 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 12/13. 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 18:12 (275) -23. This area of the sky lies in western Sagittarius some four
degrees northwest of the third magnitude star Lambda Sagittarii. This radiant is best placed near 0200 local daylight time (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, southern Serpens Cauda, western Sagittarius, Scutum, or Scorpius could be a candidate for this shower. Rates at
this time should be near one per hour as seen from the northern hemisphere and two 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.
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 sixteen 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 list below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday
night/Sunday morning.
Antihelion (ANT) - 18:12 (275) -23 Velocity - 30km/sec.
Northern Hemisphere - 1 per hr. Southern Hemisphere - 2 per hr.
*For a detailed explanation on the different classes of meteor showers and other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#X2010
Clear Skies!
Robert Lunsford
American Meteor Society
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