[Meteorobs] Observation August 11/12 2009

Sat Oct 24 12:39:16 EDT 2009

Hello all,

Now I'm catching up on old observing reports! ;)  As it turned out,  
August is a month that I won't soon forget... I had my best run of  
Perseid meteor observing in many years!  It also made up for the  
rather poor weather that plagued July.

Ivo Leupi and I had planned to stay up two entire nights to cover as  
much of the Perseids as we could close to their maximum activity.   
After a days of cloudiness, the sky finally started opening up on the  
Tuesday evening August 11.  We had contemplated traveling for several  
hours in a mad dash to get to clear skies (we even packed the cars  
ahead of time for such a scenario).  Fortunately, the last weather  
forecasts showed a clearing sky out in the west end by midnight at the  
latest.  After several email exchanges, we decided to head to  
Westmeath Lookout, a beautiful elevated rise located about 140km west  
of Ottawa, and just east of Pembroke.  Since fog was a concern, the  
elevation could be helpful.

I was the first to arrive at Westmeath Lookout, and I took my time  
setting up.  I made several runs up and down the hill to bright all  
the equipment (lawns chairs, sleeping bag, cameras and EQ mount,  
etc...).  As I was doing so, I took a few minutes break to admire the  
gorgeous sunset across a panoramic view of the Valley.  Wow!  Very  
soon, Ivo and Shane Finnigan arrived and started to setup cameras and  
another EQ mount.  A bit later on, we were joined by Chris Thuemen,  
Ken Whitnall and Brigid.  Chris setup a small refractor to enjoy some  
casual observing, while Ken and Brigid simply sat back on lawn chairs  
to catch some Perseids.

Residual clouds plagued the early evening hours, but this was not  
unexpected from the forecasts.  By 10:15pm EDT, the sky was clear and  
dark enough to begin the camera exposures and a sign-on.  I observed  
for 25 minutes while the Moon was yet to rise, counting 7 Perseids  
despite a very low radiant.  Some of these first meteors were quite  
long.  By 10:40pm, I was forced to stop observing formally due to a  
deck of patchy clouds passing by.  We waited for over an hour for  
these clouds to finally dissipate.  At 11:44pm, the sky was once again  
completely clear, and would remain so for the rest of the night!  I  
adjusted my "Moon blocker" umbrella to completely hide the glare of  
the rising Quarter Moon, and I was surprised at how well I could  
adjust to the semi-darkness.  It helped that we were blessed with good  
transparency!  The sky limiting magnitude started at a very decent 5.73.

Without wasting any time, I got my two DSLR cameras going (a Canon 30D  
and Rebel) while Ivo had his Canon Rebel XSi (all taking exposures on  
top of my Vixen GPDX mount).  Then, I signed on to observe meteors.   
For this night, I centered by field of view to the north, keeping as  
much of the Moon's glare away as possible.  I counted only Perseids,  
Kappa Cygnids and sporadics (due to other showers's radiants being too  
far off of my field of view).  I was very curious to find out if the  
predicted outburst would occur near dawn, due to Earth's passage in  
the trail left by Swift-Tuttle in 1610.

The period between 11:44pm-12:45am EDT, with just over an hour's of  
observing time, produced only low rates.  Despite the good sky  
conditions, only 11 Perseids were seen.  But the radiant was still  
fairly low, and the Moon was getting brighter.  At the end of this  
hour, I took a 33 minutes break to attend my cameras.

I settled back for the next period, 1:18am-2:15am EDT, just under an  
hour.  The limiting magnitude went down a bit to 5.5, due to the Moon  
moving higher up.  The Perseids increased with 29 meteors.  A few  
bright meteors were seen too; the best was a 30 degrees long Perseid  
that flared to mag -2.  However, the Perseids seemed quite normal, and  
maybe a bit below expectations.  There didn't seem to be anything  
unusual going on... yet.  A light breeze picked up and fog patches  
started developing all around us!  The Valley below us seemed totally  
engulfed in fog (I was glad we had picked a high spot).  I took a 19  
minutes break for a snack and to check my cameras.

The next observing round went from 2:34am-3:47am EDT, with exactly one  
hour of observing time (had a bit of dead time during this period).   
In this hour, the limiting magnitude dropped slightly to 5.45, but the  
biggest pain was the thick fog surrounding us.  The horizons got  
completely murky, and the Moon sure didn't help matters.  But  
thankfully, the sky was still OK overhead.  Despite the fog, the  
Perseids started getting interesting!  Activity seemed to improve by  
3:00am with a Perseid coming every minute.  This further increased by  
3:30am with some minutes of multiple Perseids!  I was trying to hold  
my excitement, but I couldn't help but think that maybe the predicted  
early morning outburst would come soon?  By the end of this period, I  
had logged 40 Perseids! There was now just one hour of observing time  
left before bright morning twilight.

At 3:49am EDT, it felt like someone had suddenly turned on a switch!   
The Perseids increased in brightness without warning.  A bright and  
long mag -3 Perseid with a 3 sec train went by, followed by nearly  
simultaneous mag +1 and 0 meteors!  Less than a minute later, a vivid  
mag -1 golden-yellow flew by near Cygnus, followed by a stunning mag  
-4 fireball with an 8 sec train in Ursa Major, and another fainter  
meteor right below!  Shane, Ivo and I were all cheering at the sudden  
bursts, after a long night of relatively low activity.  The minutes  
went by with more bright meteors, and another mag -4 fireball at  
3:56am!  In the span of just 5 minutes (between 3:55am-4:00am), I  
logged as many as 11 Perseids despite heavy fog surrounding us.  Was  
this the outburst??  Or would it get even better soon???

After 4:00am EDT, the rates seemed to taper off rather sharply.  A  
second "wave" of activity came between 4:10am-4:15am with 9 Perseids,  
but with average brightness meteors.  For a while, the fog cleared up,  
but it was becoming clear that we had witnessed a sharp rise of  
meteors that lasted for just a few minutes.  I continued observing  
deep into morning twilight, and I signed off at 4:50am.  At the end of  
the final hour, I had logged 59 Perseids!  Ivo finished by taking a  
number of beautiful pictures of the foggy scenery in morning light.   
As soon as the Sun started warming up the air, mosquitoes came out in  
full force.  Shane packed and took off, while Ivo and I wrapped  
ourselves into our sleeping bags and slept through the morning.

SUMMARY:  On this night, I logged a total of 162 meteors (146  
Perseids, 15 sporadics and 1 Kappa Cygnid).  The Perseids produced  
four fireballs (two of mag -4 and two of mag -3), most of which  
occurred near 4:00am EDT.  The average magnitude of Perseids was +2.06  
(over half a mag brighter than the sporadic background).  All in all,  
a night of relatively low to normal rates, but a sharp rise was  
evident near the end (corresponding to Earth's encounter with the 1610  
trail).

Now on to the second night :)

Pierre Martin
Ottawa, Ontario

DATE: August 11/12 2009
BEGIN: 02:15 UT (22:15 EDT) END: 08:50 UT (04:50 EDT)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -76.859 West; Lat: 45.793 North
Observing site: Westmeath Lookout (White Water Region), Ontario, CANADA
RECORDING METHOD: talking clock/tape recorder, cord align
----------------------------------------------------------

OBSERVED SHOWERS:_______________________________radiant position
KCG (Kappa Cygnids)______________________________18:56 +58
PER (Perseids)___________________________________02:56 +57
SPO (sporadics)
(other showers not watched)
----------------------------------------------------------

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

PERIOD(UT)____FIELD_______Teff___F_______LM_____SPO__PER__KCG

02:15-02:40___18:29 +77___0.42___1.00____6.10____1____7___0
03:44-04:45___18:29 +77___1.02___1.00____5.73____1___11___0
05:18-06:15___21:06 +71___0.95___1.00____5.50____6___29___0
06:34-07:47___21:06 +71___1.00___1.00____5.45____5___40___1
07:47-08:50___23:21 +71___1.00___1.00____5.14____2___59___0

TOTALS:___________________4.39___________________15__146__1  =  162

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), where 1.00 is exactly one hour. 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
_____-4__-3__-2__-1___0__+1__+2__+3__+4__+5______AVE

SPO___0___0___0___0___1___1___4___6___2___1_____+2.67
PER___2___2___1___6__14__26__29__35__24___7_____+2.06
KCG___0___0___0___0___0___0___0___1___0___0_____+3.00

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: 16 min (breaks)

Breaks (UT): 2:40-3:44, 4:45-5:18, 6:15-34, 6:41-49, 7:30-35, 8:30-33

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