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(meteorobs) Viewing the Quadrantids
This weekend will offer the opportunity to view the strongest annual
meteor shower, the Quadrantids. Recent ZHR's (Zenith Hourly Rates) have been
near 120 for this shower. With the Leonids quieting down to normal levels of
activity, the Quadrantids offer the richest annual display of celestial
fireworks. This shower is named for the obsolete constellation Quadrans
Muralis (Murals Quadrant), which once occupied the area of northern Bootes.
Some meteor organizations refer to this shower as the Bootids.
It is thought that this shower is related to the recently discovered
asteroid 2003 EH1. Peter Jenniskens, who discovered this relationship,
states that this object is most likely an extinct comet nucleus that appears
to be the remnant of a larger object that broke up about 500 years ago. The
Earth intersects the orbit of this object near January 3 each year. The
Earth intersects this orbit at a perpendicular angle which means we quickly
move through any debris produced by this object. ZHR's in excess of one are
produced for only five days centered on the time of maximum activity.
This year the time of maximum activity is predicted to occur at 0600
Universal Time on January 4. This corresponds to 0100 (1am) EST and 2200
(10pm on January 3) PST. Unfortunately at this time the ninety five percent
illuminated moon will be in the sky a majority of the night, obscuring all
but the brightest meteors. To see the Quadrantids at their best one must be
located at a longitude where 0600 UT corresponds to the hour before the
start of morning twilight. At this time of night the moon will have also set
allowing faint meteors to be also be seen. If maximum activity indeed occurs
at 0600 UT then the longitudes of western Europe and northwestern Africa
have the best chance of viewing the strongest activity. If it occurs earlier
then points further east have a better chance of seeing the best activity.
If it occurs later then the maximum will be lost over the Atlantic Ocean.
For observers in North America, those located along the eastern seaboard
have the best opportunity to see strong Quadrantid rates this year. At 0100
EST, the radiant is located low in the northeastern sky and the moon will be
high in the west. The peak rates are very difficult to catch for this
shower. Most observers will see approximately twenty five Quadrantids per
hour. It may be even less this year with the moonlight. This shower is
basically a Northern Hemisphere event. Observers south of the equator are
at a major disadvantage as the radiant, as seen from their location, will
not rise very high in the sky before the start of morning twilight.
The best strategy for viewing the Quadrantids this year would be to observe
when the moon is low in the west or has set. This will allow you to see
fainter meteors which make up a majority of the Quadrantid shower. It would
also be wise to face the eastern portion of the sky, especially if the moon
is still above the horizon. If you are viewing toward the Quadrantid radiant
during the late morning hours then you will see Quadrantid meteors shooting
in all directions. They will all appear to be moving away from the radiant.
True members of this shower will all have paths that trace back to northern
Bootes and intersect near the position 15:20 +49. The meteors that appear
near the radiant will be shorter and slower than those seen further away.
The Quadrantid meteors seen near the horizon will also be slower and
shorter. One will most likely also see swift meteors coming from the region
of Virgo and Coma Berenices. This is known as the Coma Berenicids or the
Northern Apex radiant. Another active radiant this time of year lies on the
Gemini-Cancer border producing slower meteors. This is known as the Delta
Cancrids or the Antihelion radiant. One should also see approximately six
random meteors per hour during the morning hours this time of year.
Sunday morning if offer the only chance to view impressive rates for the
Quadrantids this year. Activity may be seen on Saturday morning January 3,
but at much reduced rates. On Monday morning January 5, the moon remains in
the sky all night.
If you make observations of this shower, positive or not, there are several
organizations interested in your data. You may send your results to the
International Meteor Organization at visual@imodot net, the American Meteor
Society at ksyo@bellsouthdot net, the Association of Lunar and Planetary
Observers Meteors Section at lunro.imo.usa@coxdot net or the North American
Meteor Network at meteors@comcastdot net. You may also view results from
other meteor observers by joining the free meteorobs list. To join visit
http://www.meteorobs.org/
Clear Skies!
Robert Lunsford
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