During this period the moon wanes from its current full phase to a little more than one-half illuminated on January 4, 2013. This weekend the waning gibbous moon will rise during the early evening hours and will effectively ruin the sky with intense moonlight the remainder of the night. As the week progresses the moon will rise a little later each evening but the more active morning hours will still be compromised by moonlight. The strong Quadrantid meteor shower will peak on Thursday morning January 3rd, with a bright gibbous moon located near the Leo-Virgo border. Activity can be still seen from the Quadrantids if your skies are clear and transparent. It would also be wise to keep the moon out of your field of view by facing the north to east quadrant of the sky. The estimated total hourly meteor rates for evening observers this week is near two for observers located at mid-northern latitudes and one for observers in mid-southern latitudes. For morning observers the estimated total hourly rates should be near five from the mid-northern hemisphere and three from the mid-southern hemisphere. 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 during this entire period due to intense moonlight.
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 December 29/30. 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 table below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning . Details of each shower will again be provided 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|
|Antihelions (ANT)||-||07:24 (111) +21||30||00:00||1 – <1||II|
|Alpha Hydrids (AHY)||Jan 01||08:12 (123) -07||45||01:00||<1 – <1||IV|
|January Leonids (JLE)||Jan 02||09:48 (147) +25||60||03:00||<1 – <1||IV|
|Dec. Leonis Minorids (DLM)||Dec 17||11:20 (170) +26||64||04:00||<1 – <1||II|
|Coma Berenicids (COM)||Jan 01||12:20 (185) +13||69||05:00||<1 – <1||II|
|Dec. Sigma Virginids (DSV)||Dec 31||14:16 (214) +02||69||07:00||<1 – <1||IV|
|Quadrantids (QUA)||Jan 03||15:24 (231) +49||42||08:00||<1 – <1||I|