News
Meteor Activity Outlook for February 7-13, 2009
February is the only month of the year that sees a fall in rates in both hemispheres. As seen from the northern hemisphere, sporadic rates continue the fall that began in January. This will continue until June when rates reach their nadir. After a brief peak of activity in January, sporadic rates in the southern hemisphere also slide downward until March. Shower activity is low this month but decidedly more interesting in the southern hemisphere. During February there are several sources of activity in the southern morning sky. Most notable is the Alpha Centaurids, which are active during the entire month of February. Other sources are scattered from Carina through Puppis, Vela, and on into Centaurus and Lupus. None of these even rate as a minor shower but together, along with the Alpha Centaurids, create some interesting viewing during the summer nights south of the equator. Only a trace of this activity can be seen from the northern tropics. The Antihelion radiant remains north of the celestial equator and produces a modest 1-2 meteors per hour from Leo. The weak Delta Leonids become active at mid-month but are few and far between, even at maximum activity.
During this period the moon reaches its full phase on Monday February 9. At this time the moon will rise near sundown and will remain in the sky all night long. As the week progresses the moon will rise later in the evening giving a growing window of darkness just after evening twilight. The more active morning hours will still suffer from the intense moonlight. The estimated total hourly rates for evening observers this week is near one no matter your location. For morning observers the estimated total hourly rates should be near five for those located in the mid-northern hemisphere (45 N) and six for those viewing from the mid-southern hemisphere (45 S). These rates assume that you are watching from rural areas away from all sources of light pollution. 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. Rates are reduced this week due to intense moonlight.
The radiant positions and rates listed below are exact for Saturday night/Sunday morning February 7/8. 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 full descriptions of each active meteor shower will continue next week when the moon becomes less of a nuisance to observers.
The table below presents a summary of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning but may be used all week.
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 |
|
Antihelion (ANT) | - | 10:08 (152) +09 | 30 | 01:00 | 1 - 1 | II |
Alpha Centaurids (ACE) | Feb 07 | 14:08 (212) -59 | 56 | 05:00 | <1 - 3 | II |