Meteor Activity Outlook for June 11-17, 2011

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During this period the moon reaches its full phase on Wednesday June 15th. At this time the moon will lie opposite the sun and will be in the sky all night long. This weekend the waxing gibbous moon will cause problems while above the horizon. Once it sets during the late morning hours, a small opportunity will exist for viewing meteor activity between moon set and dawn. The estimated total hourly rates for evening observers this week is near two as seen from the northern hemisphere and three as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near seven from the northern hemisphere and seventeen as seen from south of the equator. 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. Evening rates are reduced due to moonlight.

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 11/12. 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 shower is expected to be active this week:

The wide Antihelion (ANT) radiant is now centered at 18:16 (274) -23. This area of the sky lies in northern Sagittarius near the faint star 11 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 southeastern Ophiuchus, Sagittarius, Scutum, Serpens Cauda, or eastern 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 one 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 two per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening rates are reduced due to moonlight.

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

RA (RA in Deg.) DEC Km/Sec Local Daylight Time North-South
Antihelions (ANT) 18:16 (274) -23 30 02:00 1 – 2 II



  • Jim Wooten 13 years ago

    MANY meteorites observed:
    Date: June 17, 2011
    Time: 21:30 – 22:30 CST
    Location: Kerrville, TX
    Apparent origin or concentration of shower: Due South about 45 to 50 degrees above horizon in an area void of bright stars (between Pisces, Aquarius, and Cetus?).
    Frequency: 15 to 20 hour
    Physical Properties: Very fast, mostly faint short streaks, a few (3 or 4/hr) bright ones, but still relatively short and fast. They were all seen in the area described above but traveled in different directions from from seemingly different points of origin.

    Reply to Jim
    • amsadmin 13 years ago

      Jim, Thanks for your interesting observation! BTW, these were meteors not meteorites. Meteorites are meteors that have reached the surface of the Earth. They could not have originated from the constellations you mentioned as this area of the sky had not yet risen above the horizon at the time you stated. Perhaps it was the area of Libra-Virgo-Serpens Caput? Did anyone else see this display?


      Robert Lunsford

      Reply to amsadmin
  • m k coe 13 years ago

    June 17, 2011 at 10:45 PM. While standing at Lat 35degrees57’45.92″N/ long 83 degrees53’41″W I saw a string of lights that looked like fireballs at approx 5 degrees above the horizon. There were approx 20 or more orbs in single file heading NE. The further the lights (fireballs) headed E they faded in brightness. They were too close to be air planes. I assumed what I was witnessing was a meteor that had broken up as it hit the earths atmosphere. I wish I had had a camera that could have photgraphed it. I hope someone else out there has seen the same sight.

    Reply to m

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