(meteorobs) Observation August 11/12 2004
Pierre Martin
dob14.5 at sympatico.ca
Fri Aug 13 18:17:33 EDT 2004
Here's my full report and data for the Wednesday night August 11/12...
I'm very glad I went out on the Perseids max night, despite the iffy
weather for Ottawa, Ontario. This was the finest Perseids display I've
ever seen! The total of 463 meteors (including 401 Perseids) seen in 5
hours teff on this night shatters my previous record (the 1997
Perseids). It also marks the first time since 1997 that I see over 100
Perseids per hour.
Considering the weather forecast, I'm surprised that it turned out so
well...
When I arrived at Bootland Farm at dusk, there was some menacing
thunder clouds forming in the distance. Some lightning flashes... and
on the opposite side was a nice colorful rainbow. At the entrance, I
found Jenny Szeto and Rick Dalrymple who had both just arrived as well.
I saw the dark clouds forming on top of us, so we rushed to setup our
tents but it was already starting to rain. Big rain drops too!
Everything was getting soaked wet. We rushed to cover up mounts and
stuff with plastic bags. Probably the most weird and interesting part
was to see some nice sucker holes forming and yet it was raining. So
there we stood, under an umbrella looking for meteors under pooring
rain! During this time we saw several nice Perseid earthgrazers
scooting across the Northern sky. Many were vividly colored and had
long paths. The best one was a mag -3 blue Perseid earthgrazer that
shot over 40 degrees into Ursa Major and left a 5 second train!
Luckily for us, the rain soon tapered off and gave way to some nice
clearing skies. For the rest of the night, we were blessed with mainly
clear skies. There was a lot of ground fog but it did not seem to
affect the skies too much high-overhead. The limiting magnitude
reached 6.5, very nice and transparent.
I signed-on for meteors just after 11pm EDT, and I started the meteor
astrophotography. Just like the previous night, I was running two SLRs
with 50mm lend and Fuji 800 film. I did 8-10 minutes exposures.
(Thanks to Michael Vasseur for supplying the mount). I kept the
cameras close to my chair and it was easy to reach them thanks to some
extra long cable releases.
Perseids were into high-gear right from the start. I was surprised to
see so much activity so early in the night with low radiant. It was a
great show. My hourly Perseids counts are in this order 48, 63, 73,
111 and 106. This makes it the most busy Perseids shower that I've
ever seen. It was also enough activity to cause a fellow observer
Jenny to fall off her chair! There were lots of dim meteors, but good
numbers of moderately bright ones as well. There were very few
fireballs. Only four of the Perseids reached fireball-class status
(one of mag -4 and three of mag -3). I felt that the Perseids seemed
brighter in the early evening than they were late a night. My average
magnitude for all Perseids on this night is +2.59.
In addition to Perseid meteors, there was decent activity coming from
other sources... I recorded 62 non-Perseids (this breaks down into 7
North Delta Aquarids, 3 South Delta Aquarids, 3 Kappa Cygnids, 2
Capricornids, 1 antihelion and 46 sporadics).
The meteors would tend to not come in regular basis - sometimes there
would be some lulls of inactivity for a few minutes followed by rapid
bursts. I noted no less than 15 instances of 2 or more Perseids
arriving within just moments of each other. It kept me and my talking
clock busy.
The most memorable sights...
- Early evening Perseid earthgrazer of mag -3, blue, 40 degrees long, 5
second train while we stood under the rain!
- At 12:31 EDT, nice mag +1 ORANGE Perseid.
- At 1:05 EDT, mag 0 color-changing Perseid yellow to green, long path.
- At 1:41 EDT, mag -4 blue Perseid fireball, long 30 deg, and with 6
sec persistent train.
- At 2:24 EDT, mag -3 Perseid fireball, flaring, with 5 sec train.
- At 2:59 EDT, mag +3 slow moving blue-green Capricornid that was seen
*fragmenting* over a long, persistent path! It gave an unusual
nebulous effect to this meteor. Nice!!
- At 3:06 EDT, long blue-green mag +1 North Delta Aquarid.
- At 3:39 EDT, spectacular mag -2 *HEAD-ON* Perseid seen almost
directly on the radiant. It barely had motion to it at all, and was
very vividly colored blue-green. Even the 2 sec train it left after
was green colored! WHOA!!
- At 4:31 EDT, bright mag -3 Perseid fireball with 4 sec train.
- At 4:39 EDT, vivid *GREEN* Perseid of mag -1.
- And last but not least at 4:43 EDT, was a sporadic of just mag +2 but
for some reason it was a very intense, almost electric BLUE-GREEN
color, nice!!
Just before 5am EDT under growing twilight, I finally signed off. I
was exhausted... but happy to have had such a good night! I slipped
into my tent and promptly fell asleep. By then, only a couple other
people were still present.
Meteor details below...
Pierre Martin
Ottawa, Ontario
DATE: August 11/12 2004
BEGIN: 0312 UT (2312 EDT) END: 0855 UT (0455 EDT)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -76 29' West; Lat: 45 23' North Elevation: 400 ft
City & Province: BOOTLAND FARM site, Arnprior, Ontario, CANADA
RECORDING METHOD: talking clock/tape recorder, plotting
-----------------------------------------------------------------------
OBSERVED SHOWERS:_____________________________________radiant position
KCG (Kappa Cygnids)____________________________18:56 (284) +58
CAP (Alpha Capricornids)_______________________21:04 (316) -06
ANT (antihelions)______________________________22:00 (330) -11
SIA (South Iota Aquarids)______________________22:28 (337) -14
NDA (North Delta Aquarids)_____________________22:16 (334) -05
SDA (South Delta Aquarids)_____________________23:12 (348) -13
PER (Perseids)_________________________________02:44 (041) +58
NPX (sporadics from north apex)________________03:00 (045) +31
SPX (sporadics from south apex)________________03:00 (045) +01
SPO (random sporadics)
-----------------------------------------------------------------------
OBSERVING PERIODS: 0 = none seen; / = shower not observed
PERIOD(UT)_FIELD____Teff__LM____PER_KCG_CAP_ANT_SIA_NDA_SDA_NPX_SPX_SPO
0312-0423__2316+53__1.00__6.40__48___2___1___0___0___2___0___0___0___7
0423-0526__0039+49__1.01__6.47__63___0___0___1___0___2___1___3___0___6
0526-0635__0048+74__1.01__6.48__73___0___0___0___0___1___2___2___1___3
0635-0744__0234+71__1.01__6.47__111__0___1___0___0___2___0___4___0___7
0744-0855__0031+77__1.04__6.26__106__1___0___0___0___0___0___2___0___11
TOTALS:_____________5.07________401__3___2___1___0___7___3___11__1___34
= 463
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 I did not spent looking at the
sky). The next 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__+6______AVE
PER____1___3___2__12__24__47__81_111__80__35___5_____+2.59
NDA____0___0___0___0___0___1___0___0___4___2___0_____+3.86
SDA____0___0___0___0___0___0___0___0___1___2___0_____+4.66
KCG____0___0___0___0___0___0___1___1___1___0___0_____+3.00
CAP____0___0___0___0___0___0___0___1___1___0___0_____+3.50
ANT____0___0___0___0___0___0___0___0___1___0___0_____+4.00
SPO____0___0___0___0___4___1___7___9__22___3___0_____+3.15
Note: Magnitude scale is to determine the brightness of sky objects.
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): None
------------------------
Dead time: 38.89 min. for breaks
Breaks (UT): 3:30(20sec), 3:45-53, 4:06-08, 4:16(15sec), 4:30(15sec),
4:42(15sec), 5:18-20, 6:12-20, 6:28(20sec), 6:31(10sec), 6:43(15sec),
6:52-54, 7:19-25, 7:37(20sec), 7:53(30sec), 7:55(20sec), 8:02-08,
8:15-16, 8:23(10sec), 8:35(15sec), 8:41(30sec)
-------------------------
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