(meteorobs) Observation December 13/14 2006 (long report and pictures)
Pierre Martin
dob14.5 at sympatico.ca
Tue Dec 26 19:10:42 EST 2006
Hello all,
I was determined to not miss this year's Geminids. It's been a few
years since I last had a good look at them under ideal conditions.
This is my favorite meteor shower and it always puts on a reliable
display under dark skies.
I didn't expect this to turn into a 1800km (1100 miles) expedition
into central Tennessee but here goes... By Monday December 11, it
was becoming painfully apparent that the weather in eastern Ontario
would NOT cooperate here at all and that I would have to travel a
significant distance if I was to have any hope of catching the
Geminids. Every few hours or so, I'd glue my eyes on the weather
maps and I'd debate whether or not I should drive so far. On Tuesday
morning December 12, I decided... "it's a GO"... I started packing
all my stuff to hit the road on my own for a long trip south across
Interstate 81 into the U.S. I left Ottawa in the afternoon, drove
all evening and all night (stopping only for gas and snacks). At
about 7am, I passed Knoxville, Tennessee. I continued west on I40
until I reached the small town of Crossville (and into a different
time zone). There, I promptly fell asleep for a few hours. I woke
up at noon, under a clearing sky and warm sunshine. The warmth felt
great... it was t-shirt weather! I picked up some groceries and then
I drove south-west another 60km or so to my destination, Fall Creek
Falls State Park. This park is located in the mountains. There is a
long steep climb on a narrow, twisting and curving road with a tall
cliff on one side. The posted "15 miles per hour speed limit" sign
is one that you DO want to follow! ;0)
After one heck of a long car trip, I finally made it to Fall Creek
Falls State Park. It's a beautiful area situated at an elevation of
1800 feet. It felt a bit eery to be one of the only campers out
there at this time of the year. After booking my camp site, I
investigated the park area to look for a good spot without trees and
light pollution where I could setup for the night. I found one large
open grassy field away from the thickness of the forest that appeared
to serve as a playground. Unfortunately, this spot was now closed
for the season. Even if I could get special permission to get in, I
would have to walk some distance to bring my stuff out in the field,
and I was concerned about a light on a small building. Still, I
figured it would be better than nothing. But you can imagine my
nervous state of mind... "Did I just drive 1800km only to be stuck
without a nice dark view of the sky?". Late in the afternoon, park
ranger Stuart Carroll showed up at my camp site and I explained my
intentions and hopes. He said I was welcome to use the open grassy
field and he added... "...but if you want, I can show you what I
think is a much better site for astronomy". So I followed Stuart's
pick up truck for about 3km. We stopped and just off the road,
inside a double-gate, he introduced me to a huge paved field with
wide horizons! Stuart explained that they designed this site to host
annual star parties and other events. I was in heaven! My reaction
to Stuart was immediate... "this will be perfect!". Stuart
graciously granted me special permission to spend the next two nights
there for astronomical activities. I returned to my campsite for
some supper and to prepare for a long night of observing. When I
drove back to the observing field, the sun had set and the sky was
darkening. I turned off the radio and turned on my favorite
planetarium music to enjoy while I kept myself busy setting up the
cameras and other equipment. Overhead, the stars kept popping out
and soon a glorious Milky Way was visible. The anticipation was
running high.
I "signed-on" at 7:10pm (local time) and I positioned my chair to
face the radiant all night. I watched for one hour to hunt for
earthgrazers while the Geminids radiant was still very low. The sky
was quite good overhead, with a limiting magnitude approaching 6.5.
There was only one small light dome in the south but otherwise no
light pollution. The temperature was cool but very comfortable
(still several degrees above freezing) and the wind was completely
calm. The transparency was between average and above-average quality
with the exception of a small haze near the horizons. It was
wonderful to be out under nice dark skies again. For the next hour,
the Geminids were surprisingly active considering the very low
radiant in the east. I logged 27 Geminids. Among these were no less
than 14 impressive earthgrazers! The most impressive Geminid seen
that hour reached a magnitude of -1, was blue-white and traced a long
40 degrees path! The longest and most persistent meteor was
actually not a Geminid but a mag +2 sporadic that come out of
nowhere, shot 60 degrees and flared four times along its path.
After this successful first observing hour, it was difficult to
resist the urge of continuing to observe but I was tired for the long
drive. I knew that I would need some shut eye if I was to tough it
out into the predawn hours. So I wrapped myself up in the sleeping
bag and napped for about an hour. When I woke up, I uncovered the
cameras and started the photography. I sprinted around the site to
get the blood flowing in my body, took a good snack and then got busy
with observing...
I had a great night and the Geminids did not disappoint! I observed
for a total of nearly 8 hours teff (effective observing time) under
clear skies and logged 699 meteors! The breakdown is 598 Geminids,
19 Monocerotids, 12 antihelions, 12 Sigma Hydrids and 58 sporadics.
This is a new personal record for me for a non-Leonid shower night.
At around 11:30pm, park ranger Stuart Carroll dropped by and kept me
company while he enjoyed just looking up at the Geminids streaking
overhead. The rates were steady every hour but reached a crescendo
late at night. Between 2:30am and 4:30am, the Geminids exceeded 100
meteors per hour even though the rising crescent moon had caused a
slight drop in my overall LM, and the Geminids radiant was lower in
the western sky.
Throughout the night, I noticed several "clusterings" of Geminids
followed by a few lulls. There was as many as 20 instances of two
meteors appearing within two seconds of each other. Even more
impressive were the simultaneous meteors... I had 7 instances when at
least two meteors were seen EXACTLY at the same time! One
particularly memorable burst occurred at 3:38am when three Geminids
streaked in different directions in just 3 seconds. I also have
several instances where 5 to 10 meteors were seen within a single
minute.
Every hour I would take a short break to get up, stretch, take a
quick run around the site, attend my cameras, and grab a snack.
Every time I looked up, I'd see some meteors. During one such break,
I happened to stare up as I was eating my chocolate fudge covered
graham cookies. Well, in the span of two cookies, I casually counted
10 meteors including a magnificent mag -4 fireball low over the
trees! As some of you know, I have a good appetite... So to see this
many meteors in the span of only two cookies tells you something :0)
The average overall Geminids magnitude was +2.3. There was many
faint meteors but there some very nice bright ones were thrown in as
well. I logged 43 Geminids of negative magnitudes, of which four
were of fireball-class. The colors seen in the brighter Geminids
were blue, yellow and green but quite a few meteors appeared pure white.
Only 6 per cent of all Geminids seen left a wake or a train. The
longest lasting train that I saw was 10 seconds. It was caused by a
gorgeous mag -3 Geminid at the zenith that bursted into a small blue-
green terminal flash.
The most interesting meteor of the night was not a Geminid. At
3:17am, an antihelion meteor appeared in Orion. It only reached mag
+3 but what made it special was how it flickered very rapidly in
brightness along its path! It was the strangest thing!
I took note of six swift moving meteors coming from a point somewhere
in Ursa Major. Unfortunately, I could no pin point a more precise
radiant since I was strictly counting and not plotting. I also
noticed four very swift, faint, short meteors from the apex area near
Leo.
While I observed, I did continuous one minute exposures with my Canon
30D and Canon Digital Rebel DSLRs. The 30D (set at ISO 640) was
operating with a Canon 16-35mm lens (set at 20mm f/2.8) and was
riding on my equatorial platform. The Digital Rebel (set at ISO 800)
had a Canon 35mm lens at f/2.0. Both cameras were pointed at
different areas of the sky but were working via a single Canon Timer
Remote Controller. I took hundreds of exposures all night and I
captured many meteors. I later digitally stacked the images that I
captured into photographs. I uploaded the photos on the gallery...
http://tinyurl.com/yefyv6
http://tinyurl.com/yfet63
http://tinyurl.com/yetlcn
http://tinyurl.com/yh3jj9
http://tinyurl.com/yjhrgk
http://tinyurl.com/yb4l4r
By a stroke of pure luck, one of the cameras captured a long duration
persistent train left behind from a fireball (which must have passed
just moments before the camera began a new exposure). Here's a video
showing the reddish train expanding over the course of 15 minutes.
It doesn't appear very bright but it expands into a wide area of the
sky (the frame's FOV from left to right covers about 20 degrees of
sky). Since this sky area was to the north and behind my head, I
didn't see any of this with my eyes...
http://www.oaog.ca/gallery2/d/15041-1/Trainmovie_001.mpg
(warning: this is a 3MB size video in .mpg format)
I signed off at 5:30am, slipped inside my warm sleeping bad and
promptly fell asleep.
Stay tune for the post-max Geminids report...
Clear skies,
Pierre Martin
Ottawa, Ontario
DATE: December 13/14 2006
BEGIN: 0110 UT (1910 CST) END: 1130 UT (0530 CST)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -85.371 West; Lat: 35.655 North Elevation: 1800 ft
City & Province: Fall Creek Falls State Park, Tennessee, USA
RECORDING METHOD: talking clock/tape recorder, plotting & cord align
-----------------------------------------------------------------------
OBSERVED SHOWERS:________________________________________radiant
position
ANT (Antihelions)________________________06:32 +23
MON (Monocerotids)_______________________06:56 +08
GEM (Geminids)___________________________07:28 +33
PUP (Puppid-Velids)______________________08:32 -45
HYD (Sigma Hydrids)______________________08:40 +01
SPO (sporadics)
-----------------------------------------------------------------------
OBSERVING PERIODS: 0 = none seen; / = shower not observed
PERIOD(UT)__FIELD_____Teff____LM____SPO___GEM__ANT__MON__HYD__PUP
0110-0211___0349+43___1.02___6.40____3____27____/____/____/____/
0345-0454___0645+35___1.00___6.45____6____69____2____3____0____0
0454-0612___0743+32___1.00___6.43____7____87____0____4____2____0
0612-0722___0832+30___1.00___6.43____10___81____4____4____5____0
0722-0830___0705+00___1.00___6.38____10___83____1____2____1____0
0830-0936___0643+21___1.00___6.30____5____100___4____3____1____0
0936-1042___0729+27___1.00___6.30____10___107___1____3____2____0
1042-1130___0821+30___0.72___6.30____7____44____0____0____1____0
TOTALS:_______________7.74___________58___598___12___19___12___0 = 699
Note: 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). The next column (LM) is the average naked
eye limiting magnitude, determined by triangle star counts. All
following columns indicate the number of meteors for each shower
observed.
------------------------
MAGNITUDE DISTRIBUTIONS:
SHOWER
______-4__-3__-2__-1___0__+1__+2__+3__+4__+5______AVE
GEM____1___3___5___34__51__73__126_134_122_49____+2.34
MON____0___0___0___0___3___1___2___5___7___1_____+2.79
ANT____0___0___0___0___1___0___1___5___4___1_____+3.16
HYD____0___0___0___0___1___0___2___3___3___3_____+3.33
SPO____0___0___1___0___2___2___8___19__19__7_____+3.17
Note: 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 (last column) for showers.
------------------------
SKY OBSCURED (FOV) (UT): None
------------------------
Dead time: 62.16 min (breaks)
Breaks (UT): 4:05-08, 4:50-56, 5:08-09, 5:42-52, 6:10-17, 6:20-23,
6:51-54, 7:12-16, 8:05-13, 8:40-43, 9:20-21, 9:23-25, 9:58-10:01,
10:04(20sec), 10:08-11, 10:50-54, 11:13(20sec), 11:25(30sec)
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