During this period the moon reaches its first quarter phase on Saturday March 8th. At this time the moon will lie 90 degrees east of the sun and will set between midnight and 0100 local standard time for sites located at mid-northern latitudes. This will allow the more active morning hours to be free of interfering moonlight this weekend. Next week though, the moon will become more of a problem as it sets approximately 45 minutes with each passing night. Toward the end of the week the nearly full moon will be in the sky most of the night making meteor observing difficult. 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 5 for observers situated at mid-northern latitudes and 11 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 evening 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 8/9. 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:
On March 14, members of the Northern March Virginids (NVI) should become visible as this shower peaks on the first day of its activity. The radiant is expected to be located at 11:34 (174) +09. This position is located near the Leo-Virgo border between the faint stars Iota Leonis and Nu Virginis. These meteors are best seen near 0100 local daylight time (LDT) when the radiant lies highest above the horizon. Rates would mostly likely be less than one shower member per hour, no matter your location. Since this radiant is located near the celestial equator, this activity can be seen most everywhere. At 22 km/sec. these meteors would have a slow velocity.
The center of the large Anthelion (ANT) radiant is currently located at 12:04 (181) -02. This position lies in western Virgo, 3 degrees west of the fourth magnitude star Zaniah (Eta 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 3 per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.
The Gamma Normids (GNO) are active from a radiant located at 15:36 (234) -51. This position lies in western Norma, 5 degrees northeast of the third magnitude star Zeta Lupi. Due to the southerly declination (celestial latitude) these meteors cannot be seen north of the northern tropical regions. They are best seen from mid-southern latitudes where the radiant lies high in the sky near 0500 local summer time. This shower peaks on March 13 but the full moon will reduce activity near that date to less than 1 per hour. At 56km/sec. the Gamma Normids would produce mostly swift meteors.
IMO shower #37 is active Wednesday March 5th through March 10th. Maximum activity was expected on the 5th from a radiant located at 15:43 (236) +42. This position is located in a extreme northeastern Bootes. The closest bright star is second magnitude Alphecca (Alpha Coronae Borealis), which lies fifteen degrees to the southwest. 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 would mostly likely be less than one shower member per hour, no matter your location. Observers in the northern hemisphere have an advantage in that the radiant lies higher in the sky during the morning hours. At 42 km/sec. these meteors would have a medium velocity.
On Tuesday March 11, activity from the Xi Herculids (XHE) should become detectable. The peak occurs on Thursday March 13th when the radiant is located at 17:11 (258) +48. This position is located in northern Hercules, five degrees southwest of the third magnitude star Rastaban (Beta Draconis). 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 37 km/sec. these meteors would have a medium velocity.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately 5 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 1 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 10 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening 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|
|Northern March Virginids (NVI)||Mar 14||11:34 (174) +09||22||01:00||<1 – <1||IV|
|Anthelions (ANT)||–||12:04 (181) -02||29||02:00||3 – 3||II|
|Gamma Normids (GNO)||Mar 14||15:36 (234) -51||56||05:00||<1 – <1||II|
|IMO #37||Mar 05||15:43 (236) +42||42||05:00||<1 – <1||IV|
|Xi Herculids (XHE)||Mar 13||17:11 (258) +48||37||06:00||<1 – <1||IV|