(meteorobs) Meteor Activity Outlook for April 3-9, 2010

[Robert Lunsford]

Meteor activity picks up a bit during April as two major showers are active during the month. The first of these, the Lyrids, are 
active from the 16th through the 25th, with a pronounced maximum on the 22nd. The Eta Aquariids start appearing near the 28th and 
reach maximum activity during the first week in May. Sporadic rates are low but steady as seen from the mid-northern hemisphere (45 
N). Sporadic rates seen from the mid-southern hemisphere (45 S) rise this month toward a maximum in July.

During this period the moon reaches its last quarter phase on Tuesday April 6th. At this time the moon lies ninety degrees west of 
the sun and rises near 0100 local daylight time (LDT) for the mid-northern latitude observer. 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 nine from the northern hemisphere and eleven 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. Morning rates are reduced due to moonlight.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning April 3/4. 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 13:48 (207) -11. This area of the sky lies in eastern Virgo, four degrees east 
of the bright first magnitude star Spica (Gamma Virginis). 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 Corvus, 
eastern Hydra, Libra, or Virgo could be a candidate for this shower. Rates at this time should be near two per hour no matter your 
location. 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 occurs on the morning of 
April 6th. The radiant is currently located at 19:56 (299) +40. This position lies in central Cygnus, six degrees west 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, 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 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 nine 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. Morning rates are reduced due to lunar 
glare.


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)) - 13:48 (207) -11   Velocity - 30km/sec.
Northern Hemisphere - 2 per hr. Southern Hemisphere - 2 per hr.

Zeta Cygnids (ZCY) - 19:56 (299) +40      Velocity - 44km/sec.
Northern Hemisphere - 1 per hr. Southern Hemisphere - <1 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