BAA Circular
Active each year between January 1-6, the Quadrantids are among the three
most productive annual showers. Rates at maximum, usually on January 3-4,
can reach one or two per minute, corresponding to corrected Zenithal Hourly
Rate 120. The maximum is usually very short-lived, with the highest activity
seen in a roughly six-hour time span. This means that opportunities to
observe the shower at its best only come round once every 3-4 years, when
the maximum is favourably timed, for a given longitude.
In 2003, maximum should occur at Solar longitude(2000.0) = 283.1o,
close to January 3d 22h UT. This is quite favourable for the British Isles.
At the time of maximum, the radiant (at RA 15h 28m Dec. +50o) in northern
Bootes will be quite low in the northeastern sky. As shown in the table
below, however, it rises rapidly in the hours through midnight, and by early
morning is high in the east. Good observed rates should be found in the
early morning hours.
Table: Quadrantid Radiant Altitudes at 53oN
Local Time Altitude Local Time Altitude
19h 14.4o 01h 27.0o
20h 12.8o 02h 33.4o
21h 12.7o 03h 40.9o
22h 14.2o 04h 48.8o
23h 17.1o 05h 57.4o
00h 21.5o 06h 66.3o
It has been some time since this shower was last well covered by BAA
observers - hardly surprisingly, the Quadrantids often fall victim to poor
weather conditions. Visual watch data obtained by the Meteor Section's
standard methods (described on the Meteor pages of the BAA website at
http://www.britastro.org) will be welcomed by the Director at the address
below.
The 2003 shower may prove productive for photography, especially after
midnight UT on Jan 3-4. Past returns have shown bright Quadrantids to become
more numerous in the hours after the visual peak.
With the Perseids and Geminids both blighted by strong moonlight, the
Quadrantids offer the best chance for a night of high-activity meteor
observing in 2003, and observers are encouraged to make best possible use of
any clear skies to cover this favourable return of the shower: the last time
we were able to accumulate large amounts of data won the Quadrantids was as
long ago as 1992!
If we ever get a clear sky that is.