While conditions are favorable for meteor observing during this period, hourly rates are expected to be low, especially from the northern hemisphere. There are no “real” radiants active during this period plus sporadic rates are low as seen from the northern hemisphere. These low rates can be blamed on the low angle at which the ecliptic (the path through the sky in which the sun, moon, and planets travel) lies during the morning hours this time of year. The ecliptic is a source of most sporadic activity and if the ecliptic lies low in the sky during the morning hours, sporadic rates will be low. As you travel southward, this angle increases and the sporadic rates will be double those seen north of the equator. Six months from now the opposite conditions will exist where northern sporadic rates will be twice as strong as those seen from the south.
During this period the moon will reach its first quarter phase on Wednesday February 25th. At this time the moon is located 90 degrees east of the sun and sets near midnight local standard time (LST). This weekend the waxing crescent moon will set during the early evening hours and will not interfere with the more productive morning hours. The estimated total hourly meteor rates for evening observers this week is near 2 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 8 for observers situated at mid-northern latitudes and 14 for observers viewing from the southern tropics. Evening rates are reduced during this period due to lunar interference. 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. 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 February 21/22. 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.
These sources of meteoric activity are expected to be active this week.
The center of the large Anthelion (ANT) radiant is currently located at 11:04 (166) +04. This position lies in a remote area of southeastern Leo. The nearest bright star, 4th magnitude Zavijava (Beta Virginis) lies 10 degrees to the southeast. Due to the large size of this radiant, Anthelion activity may also appear from Sextans, Crater, northwestern Virgo as well as Leo. This radiant is best placed near 0100 local standard time (LST), when it lies on the meridian and is located 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 Anthelion meteor would be of slow velocity.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately 6 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 12 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. Evening rates are reduced during this period due to moonlight.
The list below offers the information from above in tabular form. 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 Standard Time||North-South|
|Anthelions (ANT)||–||11:04 (166) +04||30||01:00||2 – 2||II|