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(meteorobs) Observation December 21/22 2001
Here's my full report for Friday December 21/22...
Shortly after midnight (local time), I drove to a friend's roll-off
roof observatory site near Franktown (located south-west of Ottawa,
Ontario). The last half hour drive was spent driving through a snow
squall despite forecasts calling for clear skies.
The observing site was still experiencing snowfall when I arrived
there, but things began gradually improving during the next half
hour. Two other local observers were already there. At about 2am,
the sky was almost completely clear above us yet large snowflakes
were still coming down all around us. We could very well see the
winter Milky Way but it was snowing - weird!!
I setup my observing gear and camera as the sky conditions kept
improving, and the snow finally stopped. The two other observers had
their telescopes ready, and they prepared to observe casually. The
few clouds left over had soon completely dissipated and the sky
transparency got very, very good (LM=6.65). This was one of the
clearest nights I've seen from this observing site. The winter Milky
Way and Orion were impressive. The sky stayed completely clear for
the rest of the night, so I could not have asked for better. While
getting ready to observe, I may have seen two casual Ursids.
I signed-on at 2:25 EST (local time), and watched for over 3.5 hours
TEFF. I centered my field of view to the north at 55 degrees high.
I took a number of breaks during the session to handle my camera and
warmup with hot chocolate. The temperature dipped to -14C with only
a very light wind. I was all setup comfortably in my coffin with
several layers. I also had my new heavy-duty winter sleeping bag,
hand and toe warmers, so the temperature was actually very easy to
deal with.
The first hour alone provided the most activity with as many as 9
Ursids, 2 antihelions, 1 north apex and 12 sporadics. The surprising
features of this first hour were the quick bursts of Ursids coming in
quick pairs. This had me excited. At 2:36, I saw two nice Ursids
left of Polaris within a mere 10 seconds of each other. Both were
2nd mag meteors, and I managed to get them plotted. The other
instance came at 2:58 when two Ursids went by in the western sky only
one second apart. One was a mg +2 and the other was much fainter at
mag +5. These very quick bursts followed by long lulls were strange.
For the rest of the session, Ursids rates were much weaker with 3 or
4 per hour. They were typically on the faint side. The average
magnitude for Ursids for the entire session was +3.35.
The highlights-of-the-night...
- At 2:48, an Ursid was seen going very near the zenith. It was
fairly bright at mag +1, and what made it interesting was its
nebulous appearance as it moved and slowly faded out (perhaps it was
fragmenting?)
- At 2:53, an impressive earthgrazing sporadic! It shot at least 50
degrees through the north-west sky and reached 2nd magnitude before
it disappeared.
- At 5:24, a beautiful very slow moving and persistent sporadic! It
was well seen going very high in the north-east near the zenith. It
flared to mag -1 and its path was close to 30 degrees long! I could
see a well defined meteor "head" followed by a thin wake.
Overall, I counted a total of 58 meteors. It was an enjoyable
session under dark skies, and one of the rare instances where the
weather has cooperated with the peak night of the Ursids.
Pierre Martin
Ottawa, Ontario
DATE: December 21/22 2001
BEGIN: 7:25 UT (2:25 EST) END: 11:30 UT (6:30 EST)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -76.0669 West; Lat: 45.0453 North Elevation:100m
City & Province: Franktown, Ontario, CANADA
RECORDING METHOD: talking clock/tape recorder
-----------------------------------------------------------------------
OBSERVED SHOWERS: 3-letter code; radiant position
URS (Ursids) 1428 +76
ANT (Antihelions) 0704 +22
Napx (north apex) and Coma Berenicids 1204 +15
Sapx (south apex) 1204 -15
SPO (sporadics) -
-----------------------------------------------------------------------
OBSERVING PERIODS: 0 = none seen; / = shower not observed
PERIOD(UT) FIELD Teff LM SPO URS ANT Napx Sapx
0725-0826 0522 +79 0.95 6.65 12 9 2 1 /
0826-0928 0603 +73 1.01 6.65 5 4 0 3 /
0948-1051 0653 +68 1.01 6.65 7 4 0 3 /
1051-1130 0840 +64 0.65 6.14 3 3 0 2 /
-----------------------------------------------------
TOTALS: 3.62 27 20 2 9 / = 58
-----------------------------------------------------
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 -1 0 +1 +2 +3 +4 +5 AVERAGE
SPO 1 0 0 6 10 8 11 +3.56
URS 0 0 1 5 4 6 4 +3.35
ANT 0 0 0 0 0 2 0 +4.0
---------------------------------
TOTALS: 1 0 1 11 14 16 15
---------------------------------
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: 8.24 minutes (3min for plots)
Breaks (UT): 0727 (60sec), 0829 (20sec), 0859 (30sec), 0923 (45sec),
0928 to 0948, 0950 (20sec), 1006 (1.5 min), 1030 (30sec), 1032 (20sec)
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