(meteorobs) Observation December 12/13 2007

[Pierre Martin]

Hello all,

Here's my report for the pre-max Geminids night.

I had the pleasure to have the company of Raymond Dubois.  This was a  
very cold night at -23C (-9.4F).  This session required careful  
planing ahead of time, to ensure that I'd be able to handle the  
cold.  There was a new accessory that I tried for the first time that  
was quite helpful - a propane catalytic heater.  The stream of heat  
emitted from it was mild but enough to take the edge off the cold.  I  
also had a new heavy parka, several hand warmers and my down-filled  
sleeping bag.  While Raymond and I were packing up the van, it looked  
like we were heading for a week-long polar expedition :)

By 11pm, we left Ottawa and drove over an hour to the south-west of  
Ottawa... looking for a quiet country road that had a good horizon  
and minimal local lights.  As we drove, we even spotted a few  
meteors.  We found such a spot (Weedmark road) about 15km south of  
the town of Merrickville, so we stopped and setup on the side of that  
road.  The sky overhead was quite impressive, with about 4/5  
transparency and limiting magnitude over 6.5.  The winter Milky Way  
was faintly visible among a myriad of stars, and Comet Holmes is  
looking so large to the unaided eyes that it could probably be  
mistaken for a small cloud by someone unaware of its nature.

I took my time to setup my equatorial mount and my two cameras with  
wide-angle lenses.  Raymond also had his mount to run his camera.   
(Setting up with gloves also slows down the process).  Within an  
hour, everything was ready to go!  So I programmed the cameras to do  
a series of exposures for the rest of the session - and then seeked  
my warm sleeping bag.

I observed meteors formally for two hours between 2:10am - 5:00am  
EST.  The Geminids rates were decent considering that the peak was  
over 33 hours away at that point (not counting minor showers and  
sporadics, 26 Geminids were seen the first hour, and 35 for the  
second).  Geminids were on average very faint meteors, with many in  
the mag +4 to +5 range (even a few +6!).  The brightest Geminid was a  
mag -1 meteor, but it was far from my field of view and not well seen.

The highlight was actually not a Geminid but a very well seen  
antihelion that had a graceful, slow path that reached mag -1.  It  
was almost pure white and left a delicate wake along its path.   
Beautiful!

I took note of 4 swift meteors that seemed to radiate from Ursa  
Major.  I have been noticing these meteors almost every year around  
the Geminids maximum.  Unfortunately, it's so difficult to plot when  
the weather is that cold, and when meteor rates are high enough to  
make this impractical.  At 5am, Raymond and I very carefully packed  
all our gear.  Camera wires had become very stiff due to the cold.   
There was also a small layer of frost.  Needless to say, it was quite  
brutally frigid, but enjoyable!

Last night's Geminids peak was a full washout.  I'm however expecting  
clear skies for the post-max night!

Pierre Martin
Ottawa, Ontario

P.S. I had a quick look at my photos, and at least no real bright  
meteors were captured by the cameras - I'll have a closer look for  
the fainter ones.  Raymond was telling that he captured one Geminid!


DATE: December 12/13 2007
BEGIN: 0710 UT (0210 EST) END: 1000 UT (0500 EST)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -75 49' West; Lat: 44 55' North
City & Province: Merrickville, Ontario, CANADA
RECORDING METHOD: pencil and paper method, cord align
----------------------------------------------------------

OBSERVED SHOWERS:______________________________radiant position
MON (Monocerotids)_____________________________06:36 (099) +08
GEM (Geminids)_________________________________07:08 (107) +33
HYD (Sigma Hydrids)____________________________08:20 (125) +02
COM (Coma Berenicids)__________________________11:16 (169) +27
ANT (antihelions)______________________________05:56 (089) +23
SPO (sporadics)
----------------------------------------------------------

OBSERVING PERIODS: 0 = none seen; / = shower not observed

PERIOD(UT)___FIELD____Teff____F______LM____SPO_GEM_MON_HYD_COM_ANT

0710-0810___0625+14___0.98___1.00___6.53___10__26___2___2___0___1
0839-1000___0821+15___1.13___1.00___6.53____9__35___1___0___2___1

TOTALS:_______________2.11_________________19__61___3___2___2___2  = 89

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 not spent  
looking at the sky). The 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
______-1___0__+1__+2__+3__+4__+5__+6______AVE

GEM____1___1___5___9__18__14___9___4_____+3.30
SPO____0___0___2___2___5___5___5___0_____+3.47
MON____0___0___0___1___1___1___0___0_____+3.00
HYD____0___0___0___1___0___0___1___0_____+3.50
COM____0___0___1___1___0___0___0___0_____+1.50
ANT____1___0___0___0___0___1___0___0_____+1.50

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: 14 min (breaks)

Breaks (UT): 7:16 (30sec), 7:58 (30sec), 8:10-39, 9:20-32