(meteorobs) Quadrantids from the Canadian Arctic
bmccurdy at telusplanet.net
bmccurdy at telusplanet.net
Mon Jan 5 07:12:48 EST 2009
At 4° from the Circle, Yellowknife might not technically be in the Arctic,
but you sure can feel it from here. Maybe I should just call it the land where
Celsius and Fahrenheit meet.
I hope nobody has been alarmed by my silence since mentioning my planned trip
to the frozen north. No worries, we saw lots of meteors and lived to tell about
it, however belatedly. While I was able to transcribe my tapes and send the
results to http://www.imo.net/live/quadrantids2009/ (where our observing site
really stands out on the global map!), I have been immersed in other activities
including a well-received public talk on Sunday on the recent meteorite fall in
Saskatchewan, so I have been remiss in filing a proper report.
My flight from Edmonton was delayed several hours on Friday evening, with
some real concerns that it would be diverted to Hay River due to persistent ice
fog at my destination. That really would have left me out in the cold for the
overnight maximum for the Quadrantids, but fortunately the fog had lifted by the
time the jam-packed 737 finally touched down close to local midnight. My
gracious host Stephen Bedingfield picked me up and we stayed at his home for a
little while, as our intention had always been to observe in the late overnight
hours near the peak. I figured that there would be good coverage in North
America for earlier in the evening, but that there might not be many observers
well-positioned for the expected peak just before 13h UT.
Little did we know that the Quads were already putting on a great, and
surprisingly broad, show for observers all across the continent and even in
Europe. So as it turns out our results are not particularly important in the
grand scheme of things, but well worth reporting anyway.
After pulling on the layers (including no fewer than three pairs of longjohns
in my case), we ventured out into the bitter night. The gauge on Stephen's
vehicle showed an ambient temp. of -40°, but it turned out that that was as low
as it was designed to go, and the actual temperature was actually colder than
that! There was some ice fog within Yellowknife but as we hit the open highway
it lifted to reveal a beautiful but not entirely welcome sight: a full-blown
all-sky Aurora Borealis! The intensely-green display arched across the sky,
shimmering and dancing in every direction I could look.
We drove right out onto the ice road on Vee Lake, where we pulled over just
after 3 a.m. MST. Not a single vehicle passed our location on the ice road over
the subsequent four hours. Right away it was apparent that the Quads were very
active, as both of us saw about 10-12 meteors within the first few minutes even
as we were occupied with setting up.
The bitter cold that was burning my face quickly convinced me I wouldn't last
long in the outdoor environment no matter how layered up, so in the interests of
surviving until the peak we retreated to the interior of the vehicle and opened
the moon roof (now known as the meteor roof). This unfortunately framed the
field of view, to about 80% of what I normally see unobstructed and had the
further deleterious effect of not allowing me to follow individual meteors
beyond the field of view. At times I attempted to compensate by kneeling on the
seat and sticking my head through the roof, but between the aurora and the ice
fog the sky was much brighter near the horizons so there wasn't much to be
gained. So after a couple of minutes I would sink back into the heated seat and
revert my gaze closer to the zenith. My field of view included the radiant at
all times as well as Polaris at its surprising altitude of 63 degrees.
After the early show the aurora settled down somewhat for most of our
observing session, but while less bright, large homogeneous patches remained
throughout the night, with occasional bouts of pulsating activity. That combined
with mild ice fog, intermittent thin cloud, and vehicle exhaust compromised the
sky throughout. While variable from place to place and minute to minute I
estimated the overall limiting magnitude at around 5.3 and fairly constant over
the course of the night. The sky quality meter consistently topped out right
around 20.0, plummeting to 19.6 when I pointed it in the direction of the
brighter aurora.
Throughout the entire time meteors were flashing in the sky at a steady rate.
There was relatively little clumping as these things go, and virtually no gaps
that extended beyond 3 or 4 minutes. My observed rates rose fairly steadily with
the radiant and while the rate maxed out in the hour straddling the predicted
peak it was hardly a sharp one:
Time bin | Teff | QUA | rate/min.
---------------------------------------
1024-1123 | 0.95 | 29 | 0.51
1124-1223 | 0.97 | 34 | 0.58
1224-1323 | 0.90 | 42 | 0.78
1324-1424 | 0.70 | 30 | 0.71
---------------------------------------
Totals | 3.52 | 135 | 0.64
Detailed IMO results are reproduced at bottom. In general the Quads were
relatively brief flashes across short segments of sky with few persistent
trains. While there were decent raw numbers of bright meteors, over 70% were
adjudged to be of magnitude +2 to +4. I saw 10 meteors of negative magnitude
including the night's lone identified Anthelion meteor and most of the more
colourful Quadrantids including ones of emerald green, orange, pale bronze and
ivory. I also saw a goodly number of near-point meteors over the course of the
night, many more than typical.
The best burst was during a single recording at 12:08 on my new time-stamped
digital voice recorder (a welcome Xmas gift from my son), in which in rapid
succession I saw four Quads, two of negative magnitudes including a nearly point
meteor of -2, as well as a glorious red Alpha Hydrid of mag +2 which was in full
bloom as it entered my frame of view and lasted fully two more seconds as it
gracefully arched from south to northeast and into Bootes.
We set the radio to FM 92.5, a strong transmitter in Edmonton some 1000 km to
the south. While we did experience a number of "hits", audio meteors were
outnumbered by visual ones, a rare experience which I attributed to the paucity
of transmitters within range of this northern outpost. Oddly, I did not observe
a single meteor which had a simultaneous audio counterpart; I concluded that
perhaps geometry dictated they must have been occurring only in the southern sky
beyond my field of view.
I ventured outside the vehicle for a quarter of an hour at one point where
the bitter cold of -43° seeped through even the thickest of my eight layers, and
stung the exposed flesh on my face. My observing partner, a hardy northerner,
took several such shifts but I was satisfied with just the one. The compromise
of restricted field seemed a small price to pay for creature comforts which
allowed me to hang in for a much lnegthier session that I could ever have
managed in the open. It was brutal.
While I have been in the Northwest Territories on occasion in the past it
predated my astronomy days, so it was strange to experience the large shift in
the sky. Orion beyond the crest of his arc was just beginning to cant to one
side and was already on the verge of setting. Vega and Deneb, while circumpolar
at Edmonton's latitude generally disappear into the treetops, but here they
cruised far above the northern horizon, to be joined before night's end by
Altair in a very unseasonal view of the Summer Triangle. Summer never seemed
further off.
By 6:35 local time, fully 3.5 hours before sunrise, satellites began to put
in an appearance. Given the direction of my gaze they were all polar orbiters
which seemed appropriate. Soon the dawn began to glow on the eastern horizon;
even though sunrise was still hours away the Sun was progressing at a very
shallow angle. We were both beginning to fade at this point, and after a bout of
the long blinks around 7:15 local time I agreed we had done what we could.
Exhausted but pleased with our night's work we took a circuitous route across
the ice road and back to Yellowknife, stopping for breakfast and coffee at an
icebound Tim Horton's before reaching a particularly welcoming pillow.
What a great way to begin the International Year of Astronomy!
Bruce
*****
// Header section
night 2009-01-02/03
begin 2009-01-03 1024
end 2009-01-03 1424
observer "Bruce" "McCurdy" "MCCBR"
location 114 21 34 W, 62 33 01 N
site "Vee Lake, Northwest Territories" "Canada"
reporter "bmccurdy at telusplanet.net"
// Shower section
shower QUA 230 +49
shower ANT
shower AHY 140 -10
shower COM 177 +25
shower SPO
// Number section
// Interval RA Dec Teff F Lm QUA ANT AHY COM SPO
period 1024-1123 225 +70 0.950 1.25 5.30 C 29 C 1 - / - / C
5
period 1124-1223 240 +70 0.970 1.25 5.30 C 34 - / C 1 - / C
4
period 1224-1323 255 +70 0.900 1.25 5.30 C 42 - / C 1 - / C
2
period 1324-1424 270 +70 0.700 1.25 5.30 C 30 - / C 1 C 1 -
/
// Magnitude section
// Show Interval -6 -5 -4 -3 -2 -1 +0 +1
+2 +3 +4 +5 +6 +7 Tot
distribution ANT 1024-1424 0.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 1.0
distribution AHY 1024-1424 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
2.0 1.0 0.0 0.0 0.0 0.0 3.0
distribution COM 1024-1424 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 1.0 0.0 0.0 0.0 0.0 1.0
distribution SPO 1024-1424 0.0 0.0 0.0 0.0 1.0 0.0 0.0 2.0
3.0 3.0 2.0 0.0 0.0 0.0 11.0
distribution QUA 1024-1123 0.0 0.0 0.0 0.0 1.0 0.0 1.0 9.0
7.0 6.0 5.0 0.0 0.0 0.0 29.0
distribution QUA 1124-1223 0.0 0.0 0.0 0.0 1.0 2.0 5.0 1.0
8.0 9.0 7.0 1.0 0.0 0.0 34.0
distribution QUA 1224-1323 0.0 0.0 0.0 0.0 1.0 1.0 1.0 5.0
7.0 12.0 14.0 1.0 0.0 0.0 42.0
distribution QUA 1324-1424 0.0 0.0 0.0 0.0 0.0 2.0 3.0 3.0
3.0 11.0 8.0 0.0 0.0 0.0 30.0
// Personal comments
Extreme observing near the Arctic Circle. Temp -42 C.
Most observations conducted from heated vehicle through moon roof.
Sky conditions compromised by ice fog, intermittent thin cloud,
vehicle exhaust and all-sky Aurora Borealis.
LM variable in varying directions, estimated at 5.3 overall.
Field obstruction by moon roof ~20%.
AHY = Alpha Hydrids.
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