(meteorobs) Observation December 21/22 2009 + images

[Pierre Martin]

The 2009 Ursids appeared to be modestly enhanced... a pleasant surprise!

For the Ursids night, I arrived at Johnston road at 1:00am local time,  
and took a few moments to glance up to enjoy the sky before I'd go  
setup my mount and cameras.  The temperature was -20C (-4F) and it was  
a very humid night.  A very faint meteor went by on my left, which  
looked like it might have been an Ursid... but I wasn't sure.  Mere  
moments later, any doubts of Ursids inactivity were removed when I saw  
a beautiful mag +3 average speed meteor trace a long path, gradually  
flaring in and out multiple times!  It lined up perfectly with the  
radiant.  This brought back memories of a particularly memorable  
Ursids shower that I saw in the late 80's.  Then as I was setting up,  
two faint Ursids were seen closer to the radiant.  They were soon  
followed by an impressive mag -5 Ursid fireball with a terminal flash  
and 15 sec train!  The fireball came (precisely at 1:15am EST (6:15  
UT) just as I was looking up to align my mount's polar scope.  I could  
have just as easily been looking down, and I would have missed it.  It  
sure seemed like something was going on with this shower.

Once setup and ready, I contended with an unexpected bank of clouds  
that chose to park itself above me for the next 45 minutes.  This  
delayed sign-on until 2:20am EST.  After it cleared, the sky was  
between 6.2-6.3 mag.  A very minimal amount of thin clouds were  
present throughout most of the session, as indicated in the F value  
further below.  The following three and a half hours of observing  
until dawn produced 43 Ursids.  I did not see any sharp bursts of  
activity, but they went on quite steadily until the end.  This made  
the Ursids the dominating activity of the night, exceeding even the  
sporadic background.  Some notable activity was seen from the DLM and  
COM radiants.  In the following composite image, my Canon 30D and  
16-35mm lens at f/2.8 (aimed towards Ursa Major and Ursa Minor)  
captured four Ursids and two sporadics...
http://tinyurl.com/2v5qw37

At 6:15am... had a bright and high pass of the ISS (reaching mag -4).   
Then at 6:27am, there was an unusually fast moving satellite, tracing  
a west-to-east path.

Pierre Martin
Ottawa, Ontario


DATE: December 21/22 2009
BEGIN: 07:20 UT (02:20 EST) END: 11:30 UT (06:30 EDT)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -75 06' West; Lat: 45 26' North
Observing site: Johnston road, Ontario, CANADA
RECORDING METHOD: talking clock/tape recorder, cord align
----------------------------------------------------------

OBSERVED SHOWERS:_______________________________radiant position
URS (Ursids)_____________________________________14:32 (218) +75
ANT (antihelion)_________________________________06:44 (101) +23
DLM (December Leonis Minorids)___________________10:46 (162) +31
COM (Coma Berenicids)____________________________11:48 (177) +18
SPO (sporadics)
----------------------------------------------------------

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

PERIOD(UT)____FIELD_______Teff____F_____LM____SPO__URS_COM_DLM_ANT

07:20-08:20___11:46 +75___1.000___1.00__6.20___5___13___1___2___2
08:20-09:20___13:34 +76___1.000___1.02__6.20___9___11___2___3___1
09:45-10:49___14:56 +74___1.000___1.02__6.30___7___13___1___0___0
10:49-11:30___16:12 +75___0.675___1.02__5.77___4____6___0___1___0

TOTALS:___________________3.675________________25__43___4___6___3 = 81

Notes: The first column (Period UT) refers to observing periods, 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) Teff is  
simply the total time during the observing session spent actually  
watching the sky. Breaks and/or dead time are not included in the  
reported Teff. It is reported in decimal format such that a 60 minute  
observing session would be reported as Teff = 1.00.  The column (LM)  
is the average naked eye limiting magnitude seen.  All following  
columns indicate the number of meteors for each shower observed.  For  
more info, see:http://www.namnmeteors.org/guidechap2.html
------------------------

MAGNITUDE DISTRIBUTIONS:

SHOWER
______-1___0__+1__+2__+3__+4__+5______AVE

SPO____0___1___1___4___5___7___7_____+3.48
URS____0___3___4___8___8__13___7_____+3.04
DLM____0___0___0___2___1___2___1_____+3.33
COM____1___0___1___0___2___0___0_____+1.50
ANT____0___0___0___0___0___3___0_____+4.00

Notes: 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: 4.5 min (breaks)

Breaks (UT): 9:20-45, 10:28-32, 10:48 (30 sec)