(meteorobs) Meteor Observations from California August 11, 2004
Robert Lunsford
lunro.imo.usa at cox.net
Wed Aug 11 11:34:52 EDT 2004
I just returned from a very enjoyable session on the western slopes
of Mt. Laguna. The air was clear and warm, no need for any
covering whatsoever. There was only one encounter with a flying
bug during the entire four hours. The sky was clear nearly all the
way to the coast allowing some light pollution in the western sky.
The moon rose over the hills in the east at 10:41 UT (3:41 PST).
The sky was so transparent I lost only a tenth of a magnitude
after moonrise. When the moon was covered with my hand, I
could still follow the Milky Way to the Perseus/Auriga border,
some 20 degrees from the moon. Venus was also a nice sight
10 degrees below the crescent moon.
Meteor activity was impressive the entire session. There was a dip
in activity during the third hour, probably due to fatigue. There were
several minutes during the night that produced five or more meteors.
There was once instance when two Perseid meteors appeared
simulteanously. The Perseids were brighter than expected. 19 of the
127 Perseids were negative magnitudes, peaking with a -7 fireball
that shot downward toward the northeastern horizon. The train on
that one lasted 17 seconds. The percentage of trains for the brighter
Perseids seemed less than normal. Many of these were appearing
near the radiant therefore displaying a slower angular velocity.
While a great majority of the Perseids appeared white, there were
several blue and yellow Perseids. The most outstanding Perseids
appeared a distinct coppery orange color. These appeared a bit
less often than the blue and yellow Perseids.
Since I was facing north it was impossible to properly classify
the radiants in Aquarius. I simply called all of these meteors
Antihelions. I was surprised I saw no activity from the Kappa
Cygnid radiant. I usually see a few of these slow meteors during
my Perseid sessions. A few of the Northen Apex meteors could
have accidently been called Perseids. The meteors from the
Southern Apex were far easier to distinguish.
This was a very satisfactory night and I look forward a a six hour
session tonight for the maximum. Hopefully I can get some rest
before then!
August 11, 2004
0758-0900 UT 1.03 6.64 5 ANT 25 PER 1 NPX 0 SPX
11 SPO 42 TOTAL
0900-1000 UT 1.00 6.59 3 ANT 36 PER 0 NPX 2 SPX
11 SPO 52 TOTAL
1000-1100 UT 1.00 6.58 3 ANT 30 PER 0 NPX 0 SPX
4 SPO 37 TOTAL
1100-1200 UT 1.00 6.46 1 ANT 36 PER 2 NPX 2 SPX
7 SPO 48 TOTAL
TOTALS: 4.03 6.57 12 ANT 127 PER 3 NPX 4 SPX
33 SPO 179 TOTAL
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 at an altitude of 40 degrees during the entire session. No breaks
were taken. ANT = Antihelion radiant, PER = Perseids, NPX =
Northern Apex, SPX = Southern Apex and SPO = Sporadics
(random activity).
Location: Pine Valley Viewpoint 116 29' 43" W 32 49' 49" N ELE = 1300 m
Bortle Scale Estimate: Class III Rural Sky
Beginning Temperature/Relative Humidity: 70 F (21 C) 50%
Ending " " " 72 F (22 C) 55%
MAGNITUDES:
ANT: -1 (1) 0 (1) +1 (2) +2 (2) +3 (1) +4 (4) +5 (1) AVE: +2.42
PER : -7 (1) -5 (2) -4 (2) -3 (1) -2 (4) -1 (9) 0 (16)
+1 (17) +2 (27) +3 (24) +4 (17) +5 (8) +6 (1) AVE: +1.67
NPX: 0 (0) +1 (0) +2 (0) +3 (2) +4 (1) +5 (0) +6 (0) AVE: +3.33
SPX: 0 (0) +1 (2) +2 (1) +3 (1) +4 (0) +5 (0) +6 (0) AVE: +1.75
SPO: -3 (1) 0 (1) +1 (1) +2 (6) +3 (3) +4 (10) +5 (9)
+6 (2) AVE: +3.52
Bob Lunsford
San Diego, CA USA
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