(meteorobs) Observation July 29/30 2011

Pierre Martin pmartin at teksavvy.com
Wed Aug 10 00:40:43 EDT 2011

Hello all,

I was able to enjoy a very successful meteor observing run over this  
late-July to early-August moonless window.  I managed to get 7 nights  
of observing in (up to Aug 4/5), for a combined total of 568 meteors  
seen in the span of 23.75 hours of effective viewing time.

With the weather looking promising for the last weekend of July, I  
decided to join a number of Ottawa observers for camping out at the  
very remote Irvine Lake airstrip, located just south of Denbigh  
(Ontario).  The 2.5 hours trip to get there was rather interesting.  I  
left home late, as it was getting dark, and drove straight into the  
middle of a heavy thunderstorm as I passed Renfrew.  Visibility was  
poor due to heavy rain, wind and intense lightning.  I was hoping that  
the storm would narrowly miss the airstrip, as the forecasts  
predicted.  I knew that a few guys would be be there already, with  
tents and scopes.  Barely 20km from arrival, the heavy rain stopped  
and I arrived after 10pm, relieved to see the airstrip completely  
dry.  It was a good thing I arrived so late because apparently I  
missed a wave of very nasty mosquitoes at dusk.  It was however very  
windy at the edge of the storm.  I was greeted by Joe, Sanjeev, Eric  
and Raymond who were busy packing away some things and making sure  
that they were ready in case it started to rain there.  Fortunately,  
the storm gradually moved east with occasional flashes of lightning  
that seemed to be gradually diminishing.  Overhead, the clouds were  
breaking up, the temperature cooling, the wind diminishing and... it  
was clearing!

After setting up my tent and getting organized, I signed on just after  
midnight and observed for the next four hours.  It was great to be  
under a pristine sky again, even if the transparency was a bit below  
average and the horizons looked a bit hazy.  The Milky Way was  
certainly blazing overhead.

Over the course of the morning hours, I got in 109 meteors.  Not too  
surprisingly, the Delta Aquarids were the most significant shower  
source with 30 members seen.  Many of these were rather faint with  
none being brighter than mag +1.  One of the highlights of the night  
was a pair of faint Delta Aquarids at 1:47am EDT just a split second  
apart.  The Perseids produced a steady stream of minor activity every  
hour.  There was also very good sporadic rates, especially late at  

Pierre Martin
Ottawa, Ontario

DATE: July 29/30 2011
BEGIN: 04:10 UT (00:10 EDT) END: 08:25 UT (04:25 EDT)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -77 15' West; Lat: 45 1' North Elevation: 800 ft
City & Province: Irvine Lake Airstrip (near Denbigh), Ontario, CANADA
RECORDING METHOD: talking clock/tape recorder, plotting

OBSERVED SHOWERS:_______________________________radiant position

PER (Perseids)__________________________________01:58 +54
CAP (Alpha Capricornids)________________________20:22 -10
ANT (Antihelions)_______________________________21:20 -14
SDA (South Delta Aquarids)______________________22:45 -16
PAU (Pisces Austrinids)_________________________22:56 -29
AUP (August Piscids - IMO video database)_______00:30 +18
SPO (sporadics)

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


04:10-05:10__299 +05___1.00___6.85___7___1___3___0___1___2___0
05:10-06:10__314 +04___1.00___6.89__14__10___1___4___0___3___0
06:10-07:10__330 +03___1.00___6.85__12___6___2___3___0___3___0
07:10-08:25__345 +03___1.15___6.58__17__13___0___3___0___4___0

TOTALS:________________4.15_________50__30___6__10___1__12___0  = 109

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




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.



Dead time: 6 min (break)

Breaks (UT): 7:28-34

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