Meteor Activity Outlook for April 10-16, 2010

During this period the moon reaches its new phase on Wednesday April 14th. At this time the moon lies near the sun and cannot be seen at night. This weekend the waning crescent moon will not cause any interference to meteor observers. 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 ten from the northern hemisphere and sixteen 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 positions and rates listed below are exact for Saturday night/Sunday morning April 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 14:16 (214) -13. This area of the sky lies on the Virgo/Libra border, ten degrees west of the second magnitude star Zubenelgenubi (Alpha Librae). 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 Hydra, Libra, or Virgo 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.

The team of Sirko Molau and Juergen Rendtel have discovered a weak radiant active at this time in the constellation of Cygnus. Video data shows that the Zeta Cygnids (ZCY) are active from March 27th through April 18th. Maximum activity occurred on the morning of April 6th. The radiant is currently located at 20:08 (302) +42. This position lies in central Cygnus, four degrees northwest of the second magnitude star Sadr (Gamma Cygni). The radiant is best placed during the last dark hour before dawn, when it lies highest above the horizon in a dark sky. At 44km/sec. the Zeta Cygnids would produce meteors of medium velocity. Expected rates are near one per hour during the last dark hour before dawn. Due to the northerly declination of the radiant, these meteors are not well seen from south of the equator.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately eight 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 thirteen 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.