January is best known for the Quadrantids, which have the potential of being the best shower of the year. Unfortunately this shower is short lived and occurs during some of the worst weather in the northern hemisphere. Due to the high northern declination (celestial latitude) and short summer nights, little of this activity can be seen south of the equator. There are many very minor showers active throughout the month. Unfortunately most of these produce less than 1 shower member per hour and do not add much to the overall activity total. Activity gets interesting as seen from the southern hemisphere as ill-defined radiants in Vela, Carina, and Crux become active this month. This activity occurs during the entire first quarter of the year and moves eastward into Centaurus in February and ends in March with activity in Norma and Lupus. Sporadic rates are generally similar in both hemispheres this month. Sporadic rates are falling though for observers in the northern hemisphere and rising as seen from the southern hemisphere.
During this period the moon reaches its full phase on Sunday January 4th. At this time the moon is located opposite the sun in the sky and will rise as the sun sets and set as the sun rises. This is the worse time of the month to try and view meteors and unfortunately the strong Quadrantid meteor shower reached maximum activity the same morning. As the week progresses the moon’s phase will wane but it will still greatly interfere with viewing during the early morning hours, a time when meteors are most numerous.The estimated total hourly meteor rates for evening observers this week is near 2 as seen from the northern hemisphere (45N) and 1 as seen from southern tropical latitudes (25S). For morning observers the estimated total hourly rates should be near 20 as seen from the northern hemisphere and 8 as seen from south of the equator. 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 during this period are reduced 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 January 3/4. 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. Detailed descriptions of each source will continue next week when the situation with moonlight improves.
|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)||–||07:44 (116) +20||30||00:00||1 – <1||II|
|Alpha Hydrids (AHY)||Dec 31||08:34 (129) -08||43||01:00||<1 – <1||IV|
|January Leonids (JLE)||Jan 01||09:54 (149) +24||59||03:00||<1 – <1||IV|
|Dec. Leonis Minorids (DLM)||Dec 31||11:39 (175) +24||64||04:00||1 – <1||II|
|Quadrantids (QUA)||Jan 04||15:24 (231) +49||41||09:00||15 – 5||I|