Meteor Activity Outlook for July 10-16, 2010

After several months of low activity the meteor
rates for both hemispheres see a marked increase in July. In the northern hemisphere
the change is not noticeable until mid-month when several southern radiants, the
Perseids, and sporadic rates all increase in activity. Southern rates are good all
month long.

During this period the moon reaches its new
phase on Sunday July 11th. At this time the moon will be located near the sun
and will be invisible at night. Later next week the waxing crescent moon will
enter the evening sky but will set before midnight, allowing unhampered
viewing of the morning activity. 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 twelve 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 July 10/11. 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 20:04 (301) -19. This
area of the sky lies in eastern Sagittarius. The nearest bright star is third
magnitude Dabih (Beta Capricornii), which lies some six degrees to the northeast.
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 eastern Sagittarius, Microscopium, western Capricornus,
or southeastern Aquila could be a candidate for this shower. Rates at this time
should be near two per hour as seen from the northern hemisphere and three 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.

Recent studies of the IMO video database by Sirko Molau and Juergen Rendtel have
confirmed that the July Pegasids (JPE) are still an active shower. This
shower has a much longer activity period than once thought, being active from July
7th through the 29th. Maximum activity occurs on July 10 when the radiant lies at
23:08 (347) +11. This area of the sky is located in southern Pegasus, just four
degrees south of the second magnitude star (Alpha Pegasi). This radiant is best
placed during the last hour before dawn when it lies highest in a dark sky. Even
at maximum activity hourly rates are expected to be less than one. With an entry
velocity of 68 km/sec., the average July Pegasid meteor would be swift.

Recent studies of the IMO video database by Sirko Molau and Juergen Rendtel have
revealed an active radiant in Andromeda this time of year. The c-Andromedids (CAN)
are active from July 4th through the 16th with maximum activity occurring on the 12th.
The radiant is currently located at 02:04 (031) +48. This area of the sky is
located in northeastern Andromeda, six degrees north of the famous double
star Almach (Gamma Andromedae). This radiant is best placed during the last hour
before dawn when it lies highest in a dark sky. Hourly rates are expected to be
less than one. Due to the high northern declination (celestial latitude) this shower
is difficult to view from too far south of the equator. With an entry velocity of
59 km/sec., the average c-Andromedid meteor would be swift.

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