During this period the moon reaches its first quarter phase on Friday March 30th. At that time the moon will be located ninety degrees east of the sun and will set near 0100 local daylight time as seen from the mid-northern latitudes. This weekend the waxing crescent moon will only be visible during the early evening hours and will not interfere with meteor observations. The estimated total hourly 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 seven as seen from mid-northern latitudes and twelve 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 March 24/25. 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 large Antihelion (ANT) radiant is currently located at 13:08 (197) -07. This position lies in southern Virgo, five degrees northwest of the first magnitude star Spica (Alpha Virginis). Due to the large size of this radiant, Antihelion activity may also appear from the nearby constellations of Crater, Corvus, extreme eastern Hydra and northern Centaurus as well as Virgo. This radiant is best placed near 0200 local daylight time (LDT), when it lies on the meridian and is located highest in the sky. 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 slow velocity.
This weekend is prime time to try and view any activity from the Zeta Serpentids (ZSE).Â This shower is active on only five mornings with peak activity occurring on the 24th. Rates would likely be less than one shower member per hour, even at maximum activity. The radiant is located near 17:05 (256) -04. The area of the sky is located in a blank portion of central Ophiuchus, some eight degrees northeast of third magnitude Zeta Ophiuchi. The radiant is best placed during the last dark hour before dawn, when it lies highest above the horizon in a dark sky. At 64km/sec. the Zeta Serpentids would produce mostly swift meteors.
Later in this period, activity from the Zeta Cygnids (ZCY) will begin. This activity is visible from March 27 through April 13 with maximum occurring on April 5. On the 27th theÂ radiant position lies at 19:42 (295) +38. This position lies in western Cygnus, lying directly between the third magnitude stars Delta Cygni and Albireo (Beta Cygni). The radiant is best placed during the last dark hour before dawn, when it lies highest above the horizon in a dark sky. Due to the northern declination of the radiant, this activity is not well seen from the southern hemisphere. No matter your location, rates at this time are expected to be less than one per hour. At 44km/sec. the Zeta Cygnids would produce meteors of average velocity.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately five 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 ten 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.
|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|
|Antihelions (ANT)||–||12:40 (190) -05||30||02:00||2 – 2||II|
|Zeta Serpentids (ZSE)||Mar 24||17:04 (256) -04||64||06:00||<1 – <1||IV|
|Zeta Cygnids (ZCY)||Apr 05||19:42 (295) +38||44||09:00||<1 – <1||IV|