During this period the moon reaches its last quarter phase on Sunday March 23rd. At this time the moon will lie 90 degrees west of the sun and will rise near midnight local daylight time for sites located at mid-northern latitudes. While only half illuminated, the moon will still be a nuisance during the more active morning hours. It would help to face the opposite direction from the moon to see the most activity this weekend. As the week progresses the waning crescent moon will become less of a problem with each passing night as it rises approximately 45 minutes later each night. The estimated total hourly meteor rates for evening observers this week is near 3 for observers situated at mid-northern latitudes and 4 for observers viewing from the southern tropics (latitude 25 S.). For morning observers the estimated total hourly rates should be near 6 for observers situated at mid-northern latitudes and 8 for observers viewing from the southern tropics. 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. Estimates for the morning hours are reduced this week due to interfering moonlight. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brightest meteors will be visible from such locations.
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 March 22/23. 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 sources of meteoric activity are expected to be active this week:
The center of the large Anthelion (ANT) radiant is currently located at 13:00 (195) -06. This position lies in central Virgo, 6 degrees northwest of the 1st magnitude star known as Spica (Alpha Virginis). These meteors may be seen all night long but the radiant is best placed near 0200 Local Daylight Time (LDT) when it lies on the meridian and is highest in the sky. Rates at this time should be near 2 per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.
Members of the Zeta Serpentids (ZSE) may be detectable this weekend. The half illuminated moon will pose a challenge as it lies in the same general area of the sky as the ZSE radiant. The radiant is located at 17:36 (264) +02. This position is actually located in central Ophiuchus, 2 degrees southwest of the third magnitude star Celbalrai (Beta Ophiuchi). These meteors are best seen near during the last dark hour before dawn when the radiant lies highest above the horizon in a dark sky. Rates will most likely be less than 1 per hour due to interfering moonlight. At 69 km/sec. these meteors would have a fast velocity.
The Zeta Cygnids (ZCY) become active this week but don’t peak until April 8. Therefore rates this week are expected to be extremely low, especially with interfering moonlight. The radiant is currently located at 19:12 (288) +41. This position is actually located in northeastern Lyra, mid-way between brilliant Vega (Alpha Lyrae) and 3rd magnitude star Rukh (Delta Cygni). These meteors are best seen near during the last dark hour before dawn when the radiant lies highest above the horizon in a dark sky. At 43 km/sec. these meteors would have a medium velocity.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately 4 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 2 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 7 per hour as seen from rural observing sites and 3 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Morning rates are reduced this week due to moonlight.
The table below presents a list of radiants that are expected to be active this week. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.
|SHOWER||DATE OF MAXIMUM ACTIVITY||CELESTIAL POSITION||ENTRY VELOCITY||CULMINATION||HOURLY RATE||CLASS|
|RA (RA in Deg.) DEC||Km/Sec||Local Daylight Time||North-South|
|Anthelions (ANT)||–||13:00 (195) -06||29||02:00||2 – 2||II|
|Zeta Serpentids (ZSE)||Mar 21||17:36 (264) +02||69||07:00||<1 – <1||IV|
|Zeta Cygnids (ZCY)||Apr 08||19:12 (288) +41||43||08:00||<1 – <1||IV|