(meteorobs) Observation July 29/30 2009

[Pierre Martin]

Here's my report on another fabulous night of observing!

On Wednesday evening, I left home at 10:00pm and drove about 100km  
west of the city to Stafford 2nd Line Road (a quiet country road  
occasionally used by amateur astronomer Chris Thuemen, located about  
20km south-west of Cobden).  The forecast was predicting clearing  
skies with good transparency shortly after midnight, and this time I  
was confident about its accuracy (I had my eyes glued to the satellite  
images for most of the day ;)  My objective this night was to do  
strictly meteor observing.  The late July period has long been among  
my favorite times of the year for meteors.  I just love the wide  
variety, from the slow and graceful moving Alpha Capricornids, to the  
swift moving streaks of early Perseids.  I also usually see the  
highest numbers of Delta Aquarid meteors near July 30.  Watching all  
these meteors dart against a beautiful summer Milky Way backdrop, on a  
cool comfortable night, is something I never get tired of :)

When I left home, the sky was still completely overcast.  Not one star  
could be seen.  I was wondering if I might even get some rain on my  
way out.  Fortunately there was no rain, but solid cloudiness ruled  
almost all the way.  Then, I started having doubts.  Did the clouds  
stall in their movements?  Did I mis-judge the forecast?  I sure was  
hoping that wasn't going to happen.  As I approached my destination at  
11:30pm, the Quarter Moon suddenly appeared nicely low near the  
horizon.  It could only mean one thing... the clearing was  
approaching!  Overhead, the blanket of thick clouds was suddenly  
thinning and the brightest stars began to show.  It wasn't much yet,  
but a sure sign that things were about to get a lot better.

I had no trouble at all finding the correct spot along Stafford 2nd  
Line road (thanks to the excellent directions provided by Chris).  I  
parked the car on the shoulder of the gravel road and proceeded to  
setting up my chair in the little entrance between the main road and  
the metal gate.  It took me a few minutes to position my chair  
properly, for a nice wide open view of the southern sky.  The road was  
indeed as quiet as Chris told me it would... Throughout the entire  
night, not one car went by.  The area was also very quiet, and there  
was not a single light visible around me.  Perfect!  :)  Some  
mosquitoes (and 3 or 4 bats) were out early, but they disappeared  
completely after just one hour.  Overhead, the sky was improving  
slowly but surely.  By 12:30am, the clearing was now more than halfway  
up in the west.  It was looking promising!  Some 15 minutes later, M13  
popped into view, and it was a very distinct little "fuzzball" even to  
the naked eye!  By 12:50am, the clouds continued to recede and most of  
the Milky Way was coming out into full view.  Wow!  It was good, and  
it was exceeding my expectations!  The transparency was excellent,  
with stars as faint as mag 6.8 visible at the zenith!  A wealth of  
structure was visible, and the Milky Way was well over 30 degrees  
thick in some areas.  The Milky Way soon took a three dimensional  
appearance and seemed to be buried in a vast sea of faint stars.  The  
sky was actually a lot better than I thought it would be for this  
observing site.  I suspect that the blanket of clouds lingering above  
Ottawa helped block a lot of light pollution, and kept the sky above  
me pristine.  The North American nebula's shape was distinct to the  
naked eye, M33 was visible on averted vision, and even the faint  
Zodiacal Band made an appearance during the last hour.  I could follow  
its soft glow along most of the ecliptic.  What a thrill!

I signed on for meteors at 1:00am (local time) and observed right up  
until the onset of morning twilight.  The transparency remained  
excellent and remarkably consistent throughout the night; my LM  
dropped a notch in the last period because of brightening morning sky.

In 3 hours time, I recorded a total 100 meteors (my second most active  
meteor night of the year).  The first period (one hour) produced 31  
meteors (for an average of about one meteor seen every 2 minutes).   
The second period (also one hour) was the most active with 37 meteors  
(for an average of about one meteor seen every 1.6 minutes).  The  
final period (one hour and a quarter) produced 32 meteors.  The  
southern Delta Aquarids (SDA) were quite active during the first hour  
(with 13 seen) and in the second hour (with 12 seen).  These rates are  
not too bad considering the highest elevation that this radiant gets  
to for me is only 28 degrees.  It was however interesting to see the  
SDA's appearing to drop off sharply during the last hour.  The drop in  
activity could not have been due to fatigue, because I know that I was  
fully alert right up until the end.  No fireballs were seen, although  
the SDA's were on average a bit brighter than the sporadic  
background.  Sporadics themselves were quite active throughout the  
night, especially in the second period.  A number of swift Perseids,  
as well as a few antihelions and slow-moving Alpha Capricornids were  
also seen.  I had not fewer than four instances of two meteors  
appearing within a split second of each other.  There was even a  
moment of two meteors nearly crossing paths!

All in all, it was quite a satisfying night!  And a thank you to Chris  
Thuemen for making me aware of this site.  It allowed me to get to a  
spot where the sky cleared sooner :)

Pierre Martin
Ottawa, Ontario


DATE: July 29/30 2009
BEGIN: 05:00 UT (01:00 EDT) END: 08:20 UT (04:20 EDT)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -76.994 West; Lat: 45.685 North Elevation: 300 ft
Observing site: Stafford 2nd Line, Ontario, CANADA
RECORDING METHOD: talking clock/tape recorder, plotting
----------------------------------------------------------

OBSERVED SHOWERS:_______________________________radiant position
CAP (Alpha Capricornids)_________________________20:16 -11
ANT (Antihelion)_________________________________21:04 -15
SDA (South Delta Aquarids)_______________________22:28 -17
PAU (Pisces Austrinids)__________________________22:36 -31
PER (Perseids)___________________________________01:32 +53
SPO (sporadics)
----------------------------------------------------------

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

PERIOD(UT)____FIELD_______Teff____LM____SPO_ANT_CAP_SDA_PAU_PER

05:00-06:01___21:05 +05___1.02___6.73___10___5___0__13___0___3
06:05-07:05___22:10 +06___1.00___6.73___16___3___1__12___0___5
07:05-08:20___23:16 +06___1.25___6.63___16___1___2___7___0___6

TOTALS:___________________3.27__________42___9___3__32___0__14  =  100


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
_____-1___0__+1__+2__+3__+4__+5__+6______AVE

SPO___1___2___1___9___9___8__11___1_____+3.29
SDA___0___1___6___4___6__11___4___0_____+3.00
PER___0___0___2___3___5___2___1___1_____+3.00
ANT___0___0___1___1___3___1___3___0_____+3.44
CAP___0___0___0___0___1___1___1___0_____+4.00

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: none

Breaks (UT): 6:01-05