Meteor Activity Outlook for June 16-22, 2012

During this period the moon reaches its new phase on Tuesday the 19th. At this
time the moon will be located near the sun and will not be visible at night.
This weekend the slender crescent moon will rise just prior to dawn, not causing
any problems to meteor observers. The estimated total hourly meteor rates for
evening observers this week is near three 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 as seen from mid-northern
latitudes and thirteen from mid-southern latitudes. 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 16/17. 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 large Antihelion (ANT) radiant is currently located at 18:32 (278) -23. This
position lies in central Sagittarius, two degrees north of the third magnitude
star Kaus Borealis (Lambda Sagittarii). Due to the large size of this radiant,
Antihelion activity may also appear from eastern Scorpius, southeastern
Ophiuchus, Serpens Cauda, Corona Australis, and Scutum as well as Sagittarius.
This radiant is best placed near 0200 LDT, when it lies on the meridian and is
located highest in the sky. Rates at this time should be near one per hour as
seen from the northern hemisphere and two as seen from south of the equator.
With an entry velocity of 30 km/sec., the average Antihelion meteor would be of
slow velocity.

Studies by Sirko Molau and Juergen Rendtel of the IMO’s video data has revealed
an active radiant located in Pisces this time of year. The Delta Piscids (DPI)
are only active from June 20th through the 24th with maximum activity occurring
on the 23th. The radiant position at maximum is located at 00:44 (011) +06. This
area of the sky lies in south-central Pisces, just southwest of the fourth
magnitude star Delta Piscium. This radiant is best placed just before dawn when
the radiant lies highest in a dark sky. Rates, even at maximum activity, should
be less than one per hour no matter your location. With an entry velocity of 71
km/sec., the average delta Piscid meteor would be swift.

As seen from the mid-northern hemisphere (45N) one would expect to see
approximately seven 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 eleven
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 table below presents a condensed version of the expected activity this week.
Rates and positions are exact for Saturday night/Sunday morning.