(meteorobs) Meteor Observations from California August 12, 2004

[Robert Lunsford]

Thunderstorms developed over the mountains Wednesday afternoon and the
remainder of the day and the early evening was partly cloudy with scattered
altocumulus from the dissipating thunderstorms. Joseph Assmus and I arrived
at our site at 9:30pm and to our amazement we had the entire place to
ourselves. We avoided Mt. Laguna on the max night as it is always a zoo up
there with headlights constantly shining in your eyes. This spot is well off
the beaten path approximately ten miles south of George Zay's old
observatory site in Descanso. The sky was clear when we arrived with only a
couple of easily avoided patches of altocumulus. Unfortunately the sky was
clear all the way to the coast and the light dome to the west reduced
limiting magnitudes.

Perseid activity was going full tilt while we set up. There were Perseid
earthgrazers shooting in every direction every 30 seconds or so it seemed.
Naturally when we were ready to count they died down. The first "official"
meteor of the session was a nice orange zero magnitude Kappa Cygnid. I
counted a total of 16 Perseids the first hour. Rates rose quite nicely
during the second hour as 49 Perseids were recorded. At this point it looked
like a tremendous night was ahead of us. For some reason rates fell off
considerably during the third hour (1245-145am PDT). Only 35 Perseids were
seen with several long gaps between meteors. Luckily rates surged during the
fourth hour (145-245am PDT) and 73 Perseids were recorded. The fifth hour
was even better with 79 Perseids and 18 sporadics recorded (just shy of 100
meteors!). Joseph had to leave by this time and he took all our luck with
him. The altocumulus that had been blocking the moon low in the east now
drifted overhead and cut my rates at least in half. Only 39 more Perseids
were seen before I called it quits at 445am PDT.

During the five hour watch I ended up with 291 Perseids, a bit shy of what I
had hoped for but I'll take it over being totally cloudy the entire night.
Although several -5 fireballs were seen, my overall impression was that the
Perseids were not as bright as the previous night. The best Perseid of the
night was not the brightest. It occurred close to the radiant in Cassiopeia.
It was a -3 distinctly golden meteor with a train that turned vivid green
before disappearing. Of the three -5 Perseids, two of them occurred close
to the horizon and the third shot through the eastern with several flares.
The
highlight of the night was a -5 sporadic that shot out of the southeastern
sky and streaked over half the sky into the northwest. It also flared
several times and was brilliant blue color.

On to the totals:

August 12, 2004

0545-0645 UT    1.00   6.43   0 ANT  1 KCG   16  PER  0 NPX   0 SPX
                                                2  SPO  19  TOTAL

0645-0745 UT    1.00   6.39   2 ANT   0 KCG  49  PER  0 NPX   0 SPX
                                               6  SPO  57  TOTAL

0745-0845 UT    1.00   6.44   2 ANT   0 KCG  35  PER  0 NPX   0 SPX
                                                8 SPO   45  TOTAL

0845-0945 UT    1.00   6.39   2 ANT   0 KCG  73  PER  0 NPX   2 SPX
                                                8 SPO   85  TOTAL

0945-1045 UT    1.00   6.34   0 ANT   0 KCG  79  PER  0 NPX   1 SPX
                                                18 SPO   98 TOTAL

1045-1145 UT*  1.00   6.31   0 ANT   1 KCG  39  PER  0 NPX   0 SPX
                                                6 SPO   46 TOTAL

TOTALS:            6.00   6.38   6 ANT   2 KCG  291  PER  0 NPX   3 SPX
                                               48 SPO   350 TOTAL

* The sky was 50% obscured during the last hour of the session

The first column gives the period watched stated in Universal Time (UT)
which is PDT + 7 hours. The second column gives the percent of that
particular hour actually spent observing the sky. The third column gives
the average limiting magnitude estimated during each period. The last
several columns list the activity seen during each period. I was facing
north northwest at an altitude of 50 degrees during the entire session.
No breaks were taken.  ANT = Antihelion radiant, KCG = Kappa
Cygnids, PER = Perseids, NPX = Northern Apex, SPX = Southern
Apex and SPO = Sporadics (random activity).

Location: Japatul Helipad 116 40' 04" W 32 44' 52" N  ELE = 750 m

Bortle Scale Estimate: Class IV Rural/Suburban Transition

Beginning Temperature/Relative Humidity: 68 F (20 C) 71%
Ending              "               "             "        70 F (21 C) 60%

MAGNITUDES:

ANT:  -1 (0) 0 (1)  +1 (0) +2 (3) +3 (1) +4 (1) +5 (0)   AVE: +2.17

KCG:  -1 (0) 0 (1)  +1 (0) +2 (1) +3 (0) +4 (0) +5 (0)   AVE: +1.00

PER : -5 (3) -4 (1) -3 (5) -2 (5) -1 (11) 0  (25) +1 (45) +2 (71) +3 (64)
         +4 (40) +5 (21) +6 (0)  AVE: +2.02

SPX:  0 (1) +1 (0) +2 (1) +3 (1) +4 (0) +5 (0) +6 (0)    AVE: +1.67

SPO:  -5 (1) 0 (1) +1 (3) +2 (12) +3 (12) +4 (10) +5 (9) +6 (0)
           AVE: +2.98

Bob Lunsford
San Diego, CA USA