(meteorobs) Observation December 13/14 2010
Pierre Martin
pmartin at teksavvy.com
Tue Dec 28 17:37:55 EST 2010
Hello all,
To escape the poor weather a couple of weeks ago, and to seek clear
dark skies, Raymond Dubois and I drove for 19 hours (1800 km) to
Georgia (U.S.A.) to catch the Geminids under clear skies. We were
determined to see the peak! It may sound crazy to go that far for a
single night of observing, but for this meteor shower, I felt it was
worth it :) We left Ottawa on the Saturday morning December 11 (with
my car jammed packed of camping and camera gear), and drove all day on
Interstate 81. We stopped to sleep at a motel in Maryland, where we
had the opportunity to check the latest weather forecasts with
Raymond's netbook (showing iffy weather throughout Sunday but clear
and great on Monday). The following day, we got going at 7 am, and
for Maryland, it was a bit nippy at -8C. Our goal was to arrive at
the Deerlick Astronomy Village in the evening hours. As we trekked
further south, the temperature gradually rose, and then declined
depending on the altitude. Along a good stretch of the Appalachians
in Virginia, we would occasionally hit snow and rain. We saw several
salt trucks standing by, in case the interstate would turn nasty.
Fortunately, the roads were in good condition, as the ground appeared
too warm to freeze or accumulate any significant snow fall or ice. As
we moved into the Carolinas along Interstate 77, the change of scenery
seemed sudden, going from patches of snow along the side of the road
to green grass, leaves and even palm trees! The temperature was
hovering just above freezing, so still a lot colder than usual for
these areas.
By 7:00pm on Sunday Dec 12, we were rolling into the Deerlick
Astronomy Village (DAV). The temperature was a bit below freezing,
the wind was howling and a few scattered snow flurries were coming
down (nothing accumulating on the ground though). Being our first
time there, and not too sure what to expect, we moved in slowly. When
we got to the gate, it was open. Out at the observing field, the warm
room cabin was open, and one of the toilet/showers was open as well.
As it turns out, the DAV owners were expecting us and very kindly
arranged to make the site as comfortable as possible for us. Wow! We
spent a few minutes looking around the site to familiarize, and we
were very impressed at the accommodations present there. What a
beautiful site... Very dark skies, open horizons with a low tree line,
well maintained short grass, a large permanent pavilion for star party
events, multiple AC power outlets along an entire row in the field, RV
power outlets, two large concrete platforms for setups, internet
access, a heated cabin with red lights (incl microwave, fridge, water)
and even another building with hot showers & flush toilets on the
field! Compared to any of the observing sites that I am used to at
home, these accommodations truly felt luxurious. When Raymond spotted
an active webcam outside the cabin, facing the observing field, we
stood outside and waved at it with our lights, just in case someone
was watching :) The only thing missing on the Sunday night was clear
skies. The cold front was pushing forward, and it was very windy,
giving a windchill factor as low as -15C. This meant putting on our
full layers and our big parkas, like we normally would on very cold
nights in Ottawa. Overhead, the low clouds would occasionally break
to reveal some brief clear holes. I spent a few minutes just looking
up, and I enjoyed a few early Geminids. We were exhausted from the
long drive, so we didn't mind the poor conditions so much. A quick
look up on the internet confirmed that the overcast skies would
persist, and that it would not clear up for good until morning. I
setup my tent while Raymond settled inside the cabin to sleep there.
After that, it wasn't long before we were both sound asleep. I woke
up shortly after 4 am to check the sky, and there was no real
improvement with lots of low clouds, and just the odd clear break.
After catching up on sleep through the entire morning (I think it was
noon when I got up), Raymond and I woke up under sunny skies without a
single cloud in sight. We spent the afternoon chatting with some of
the DAV crew who dropped in to say hi, and we saw the "Village"
portion of the DAV where several large amateur observatories are setup
next to houses and cabins... very lovely, truly an astronomical
observing resort! Then we drove to the town of Thomson to get a good
meal and pick up groceries. Along our way, we got distracted by a
flock of turkey vultures flying low and surrounding us on a quiet
road :) Raymond managed to get some pictures. Once back at the DAV
in the late afternoon, we took our time setting up our cameras and
mounts on one of the concrete platforms. The Sun was dropping
quickly, and our anticipation was building. The sky looked terrific,
with excellent transparency... not the slightest hint of any haze!
The strong wind was somewhat subsiding, and the evening weather was
comfortable at 0C given that we were very well dressed for it. We
were ready for a long night of observing!
I signed on for meteors at 7:15pm, just as the Geminids radiant was
coming up over the north-east horizon. I also started the camera
exposures, to try and capture the earthgrazers. It was interesting to
see the sky at 33 degrees latitude. Judging by just how much lower in
the sky Polaris appeared, the 12 degrees of difference compared to
Ottawa's was quite evident :) Orion was seen rising up at a steeper
angle than I am used to. Later on in the night, I spotted the second
brightest star in the night sky, Canopus, low in the south in the
constellation Carina (something we never get to see in Ottawa). I was
impressed at the sky quality with the Quarter Moon lying high up in
the south-west. The 5th mag star in Ursa Minor was visible even very
low in the sky. Observing for an hour, from 7:15-8:15pm, I saw 10
Geminids and 2 sporadics. Nearly half of these meteors were
earthgrazers. The most impressive was a mag +3 Geminid seen at 7:53pm
that travelled over 50 degrees in the north. It wasn't particularly
bright but it flared repeatedly and faded out very gradually. At the
end of this first hour, I took a two hour break to have supper and
wait for the Moon to get lower.
When I came out to resume observing at 10:30pm, the sky was
significantly better. Geminids were clearly increasing, with some
bright and longs meteors. As I walked back to the setups, bright
GEM's flashed overhead including mag -1 and mag 0 meteors in the
south, just two seconds apart! Moments later, a mag 0 Geminid went
right in front of the Orion nebula! As I adjusted my cameras, another
bright Geminid flashed by, this time a mag -2! With the Moon lower in
the west, the sky LM was significantly better, reaching mag 6.2 near
the zenith. The radiant was also quickly rising in the east. I was
eager to get in my chair, inside my warm sleeping bag :)
Between 10:30pm-11:30pm, I saw 50 meteors (47 Geminids, 2 antihelions
and 1 Monocerotid). Several colorful Geminids were seen. The best
was a mag -4 blue-green Geminid fireball seen at 11:08pm low in the
south in Eridanus, that left a 1 sec train. Another notable meteor
came at 11:26pm... a mag -3 blue-green Geminid low in the south-west.
I noted five instances of seeing two Geminids appearing within one or
two seconds of each other, and even two simultaneous Geminids!
The next period between 11:30pm-12:48am, amounted to exactly 1 hour of
effective observing time (I took a 2 minute break to let a car come
in, and then a 16 minutes break to wake up Raymond and attend my
cameras). The sky was darkening with the setting Moon, averaging mag
6.3 at the zenith. I saw a total of 69 meteors (65 Geminids, 2
Monocerotids, 1 Sigma Hydrid and 1 antihelion). Oddly, this hour had
not one sporadic meteor. The finest Geminid of the night appeared at
11:47pm... It was a brilliant blue-green mag -4 fireball that scooted
20 degrees into Eridanus. It fragmented into two distinct pieces of
equal brightness, one lagging behind the other slightly. (Fragmenting
Geminids are infrequent, but I typically see one or two of these on a
good night of maximum activity. When they occur, they are spectacular!)
The next period between 12:48am-2:10am, amounted to a little over an
hour of effective observing time (breaks and time spent looking down
subtracted). With the Moon out of the way, the sky was gorgeous,
reaching mag 6.6. The Milky Way was evident and there was a sea of
faint stars surrounding the bright winter constellations. The
Geminids were now kicking into high gear! It was a busy hour, with a
total of 137 meteors (120 Geminids, 7 sporadics, 3 antihelions, 2
Monocerotids, 2 December Leo Minorids, 1 Puppid-Velid, 1 Sigma Hydrid
and 1 Coma Berenicid). At times, several Geminids came in a short
span of time, or even within seconds apart! One particularly
impressive burst was the 7 Geminids appearing within a single minute!
I was sometimes busy enough that I felt urged to speak rather quickly
in my tape recorder :) No fireballs were seen during this hour - the
GEM's had a good share of both dim and bright meteors. The most
impressive meteor of this hour came at 1:05am... It was a 50 degrees
long mag +3 sporadic earthgrazer that dropped fragments as it moved
slowly, taking several seconds to cross the sky from Ursa Major to
Gemini.
At 2:10am, I reluctantly signed off. I suddenly felt ill with an
upset stomach, and couldn't continue. It was disappointing to stop
observing, with the gorgeous sky overhead and Geminids flying left and
right. I went inside the warm cabin and settled in to rest, hoping
that I'd be OK for some more observing in an hour or two. Instead, I
was clearly out of action for the remainder of the night. Raymond
continued to observe through the early morning hours, and took care of
handling all of the camera equipment at the end (merci Raymond!).
Despite this set back, it was a terrific night, and at least all the
cameras worked continuously without any issues until morning dawn. I
ended up observing over 4 hours of effective observing time, and saw a
total of 268 meteors (242 Geminids, 9 sporadics, 6 antihelions, 5
Monocerotids, 2 Sigma Hydrids, 2 December Leo Minorids, 1 Puppid-Velid
and 1 Coma Berenicid). So I certainly consider the night and the trip
to be a success!
After sleeping through the morning, I woke up feeling better and was
able to have a light breakfast. Raymond and I packed the remaining
equipment, and we took off for the long 2 day road trip back home.
I'd like to express my appreciation to Chris Hetlage, Mike Boni and
Jerry Tarter who graciously welcomed us at DAV and made the experience
as comfortable and enjoyable as possible for us. What a great
location! If the long distance wasn't a factor, I would want to do
all my observing there. It goes without a doubt that I'll keep DAV in
mind in case of future travel plans to the southern U.S. :)
NAMN report copied below:
Clear skies,
Pierre Martin
Ottawa, Ontario
DATE: December 13/14 2010
BEGIN: 00:15 UT (19:15 EST) END: 07:10 UT (02:10 EST)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -82 45' 47" West; Lat: 33 33' 41" North
City & Province: Deerlick Astronomy Village, Georgia, USA
RECORDING METHOD: talking clock/tape recorder, cord align
----------------------------------------------------------
OBSERVED SHOWERS:_______________________________radiant position
GEM (Geminids)__________________________________07:28 (112) +32
ANT (Antihelions)_______________________________06:12 (093) +23
MON (Monocerotids)______________________________06:48 (102) +08
PUP (Puppid-Velids)_____________________________08:08 (126) -45
HYD (Sigma Hydrids)_____________________________08:16 (129) +02
COM (Coma Berenicids)___________________________11:30 (172) +19
DLM (December Leo Minorids - IMO video)_________10:22 (155) +34
DAD (December Alpha Draconids - IMO video)______14:00 (210) +58
----------------------------------------------------------
OBSERVING PERIODS: 0 = none seen; / = shower not observed
PERIOD(UT)___Teff__FOV___LM____GEM__SPO_ANT_MON_PUP_HYD_COM_DLM_DAD
00:15-01:15__1.00__E50___5.35___10___2___0___/___/___/___/___/___/
03:30-04:30__1.00__SE50__6.18___47___0___2___1___/___0___/___/___/
04:30-05:48__1.00__SE50__6.30___65___0___1___2___0___1___0___0___0
05:48-07:10__1.15__S50___6.53___120__7___3___2___1___1___1___2___0
TOTALS:______4.15_______________242__9___6___5___1___2___1___2___0 =
268
Note: The first column (Period UT) refers to the observed periods, in
Universal Time. The second column (TEFF) is the effective observing
time, it is minutes/60. The column FOV is the general direction I was
looking in the sky (i.e. E50 = east at 50 degrees elevation). The
column (LM) is the average naked eye limiting magnitude, determined by
the triangle star counts method. 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___2___1___2___8__18__23__45__55__56__32_____+2.64
SPO___0___0___0___0___0___1___1___3___2___2_____+3.33
ANT___0___0___0___0___1___3___0___1___1___0_____+1.66
MON___0___0___0___0___0___0___2___1___2___0_____+3.00
HYD___0___0___0___0___0___1___0___0___0___1_____+3.00
DLM___0___0___0___0___0___0___1___0___1___0_____+3.00
PUP___0___0___0___0___0___0___0___0___1___0_____+4.00
COM___0___0___0___0___0___0___1___0___0___0_____+2.00
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
(IMO definition). The above table contains the magnitudes from all
observed meteors, and the average (last column) for showers.
------------------------
SKY OBSCURED (FOV) (UT): None
------------------------
Dead time: 31 min (breaks)
Breaks (UT): 4:38-39, 4:43-44, 5:30-46, 6:18-31
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