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(meteorobs) Observation December 11/12 2001
Last night (Dec 11/12), I joined a number of observers at the
Casselman site to watch for Geminids under excellent conditions. The
sky was quite transparent when I got there, allowing limiting
magnitude 6.4. Glows from distant cities were also much less
noticable than usual. Still no snow on the ground, and temperature
was a cool but comfortable -5C. After several minutes spent fumbling
with equipment, I finally "signed-on" at 1am local time. For this
session, I faced south toward the GEM radiant.
Meteor activity was very enjoyable! The Geminids again more than
doubled their intensity from the previous night. After 3 hours TEFF
(effective observing time), I recorded a total of 115 meteors (73
Geminids, 7 Chi Orionids, 5 Sigma Hydrids, 4 Monocerotids and 26
sporadics). The Geminids accounted for 84% of the activity. There
were occasional bursts of a few minutes followed by periods of
quieter activity. At 2:47am (local time), a Sigma Hydrid and
sporadic shot swiftly in the SE within just one second!
The highlight-of-the-night came at 3:29am (local time) when a
dazzling Monocerotid fireball appeared in the south. It had an
electric blue terminal flash reaching magnitude -6! The fireball was
average speed and left behind a train lasting for 8 seconds. The
beginning and end of this meteor was well seen in my field of view.
There was also a strange "worm" sporadic meteor. It was magnitude +3
and flared in and out at least three times near the zenith.
The Geminids seemed to be more on the faint side. They had only
three meteors in the negative magnitudes (all of which were minus
ones).
Overall, a very productive session.
Pierre Martin
Ottawa, Ontario
DATE: December 11/12 2001
BEGIN: 6:00 UT (1:00 EST) END: 9:12 UT (4:12 EST)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -75.063 West; Lat: 45.269 North Elevation:100m
City & Province: Casselman, Ontario, CANADA
RECORDING METHOD: talking clock/tape recorder
-----------------------------------------------------------------------
OBSERVED SHOWERS: 3-letter code; radiant position
GEM (Geminids) 07h08 +33
MON (Monocerotids) 06h40 +08
XOR (chi Orionids) 06h08 +23
HYD (Sigma Hydrids) 08h20 +02
Napx (north apex) 11h08 +20
Sapx (south apex) 11h08 -10
SPO (sporadics) -
-----------------------------------------------------------------------
OBSERVING PERIODS: 0 = none seen; / = shower not observed
PERIOD(UT) FIELD Teff LM SPO GEM XOR HYD MON Napx Sapx
6:00-7:07 06h41 +09 1.00 6.40 4 25 0 1 0 1 0
7:07-8:09 07h29 +12 1.03 6.40 6 21 3 2 1 3 1
8:12-9:12 08h58 +11 1.00 6.40 11 27 4 2 3 0 0
-------------------------------------------------------------
TOTALS: 3.03 21 73 7 5 4 4 1 = 115
-------------------------------------------------------------
The first column (Period UT) refers to observing periods broken down
as close as possible to one hour of true observing, in Universal
Time. The second column (Field) is the area in in the sky where I
centered my field of view. The third column (TEFF) represents
effective observing time (corrected for breaks or any time I did not
spent looking at the sky). One hour = 1.00 teff. The fourth column
(LM) is the average naked eye limitimg magnitude, determined by
triangle star counts. All following columns indicate the number of
meteors for each shower observed.
MAGNITUDE DISTRIBUTIONS:
SHOWER -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 AVERAGE
SPO 0 0 0 0 0 0 2 3 1 11 7 2 +2.92
GEM 0 0 0 0 0 3 2 4 15 15 19 15 +3.11
XOR 0 0 0 0 0 0 1 1 0 2 0 3 +3.14
HYD 0 0 0 0 0 0 0 1 0 1 3 0 +3.20
MON 1 0 0 0 0 0 0 0 0 2 1 0 +1.0
------------------------------------------------------
TOTALS: 1 0 0 0 0 3 5 9 16 31 30 20
------------------------------------------------------
Note: Magnitude scale is to determine the brightness of sky objects.
Magnitude -8 is comparable to a quarter moon, magnitude -4 with the
planet Venus, magnitude -1 with the brightest star Sirius, magnitude
+2 to +3 with most average naked eye stars and magnitude +6 to +7 are
the faintest stars the naked eye can see under typical dark
conditions. A meteor of at least magnitude -3 is considered a
fireball. The above table contains the magnitudes from all observed
meteors, and the average for showers.
SKY OBSCURED:
None
------------------------
Dead time: 7 minutes
Breaks (UT): 6:07-6:09, 6:18-6:23, 8:09-8:12
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