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(meteorobs) July 18/19 Observations From California
I observed from the western foothills of the Laguna Mountains this
morning for 3 hours. The weather was a bit cool but the skies were
perfectly clear. The rates were much better than last week as I managed
to count 37 meteors. The active radiants included the Alpha
Capricornids, Pisces Austrinids, Perseids, and the South Delta Aquarids.
One possible member of the Alpha Cygnids was also plotted. There were
also 3 meteors that lined up with both the North Delta Aquarids and the
Anthelion radiant, now located in west central Capricornus. Length and
velocity criteria fit both radiants for all 3 meteors. I listed them as
Anthelion meteors (Sigma Capricornids from Gary Kronk's book) since the
maximum for this shower is much closer than that for the NDA's.
Activity was constant during the first two hours as I recorded 10 and 11
meteors. The last hours was the most active as 16 meteors were seen. The
Perseids were the most active shower producing 4 meteors during the
session. The highlight of the night was an orange second magnitude
Perseid that left a one second train almost directly over Alpha Persei.
It was not the brightest meteor of the night but the most impressive.
There was also a -2 CAP seen at the edge of my field low in the northern
sky that would have been more impressive if I had a better view of it.
The limiting magnitude estimates were remarkably constant tonight.
Twelve different estimates were taken throughout the night involving 4
different areas. The range from the resulting estimates was only 6.44 to
6.60. It helped that I stopped observing well before the onset of
nautical twilight resulting in very dark skies in all three periods.
July 18/19 1999
UNIVERSAL
TIME
0830-0930 0.94 6.53 0 ACG 2 ANT 2 CAP 0 PAU 1 PER 0 SDA 5
SPO 10
TOTAL
0930-1030 0.93 6.55 1 ACG 0 ANT 1 CAP 1 PAU 1 PER 1 SDA 6
SPO 11
TOTAL
1030-1130 0.89 6.55 0 ACG 1 ANT 0 CAP 1 PAU 2 PER 0 SDA 12
SPO 16
TOTAL
TOTALS: 2.76 6.54 1 ACG 3 ANT 3 CAP 2 PAU 4 PER 1 SDA 23 SPO
37 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. Time was lost for
plotting and data entry tonight. The third column gives the average
limiting magnitude estimated during each period with a minimum of 4
estimates using at least 2 different sky areas close to my center of
view. The last several columns list the activity seen during each
period.
I was facing east at an altitude of 70 degrees all night. No breaks were
taken during this session. ACG = Alpha Cygnids, ANT = Anthelion Radiant
or Sigma Capricornids, CAP = Alpha Capricornids, PAU = Pisces
Austrinids, PER = Perseids, SDA = South Delta Aquarids, and SPO =
Sporadic (random activity).
Beginning Temperature/Relative Humidity: 48 F (9 C) 43%
Ending " " " 50 F (10 C) 39%
MAGNITUDES:
ACG: +3 (1) AVERAGE: +3.00
ANT: +3 (2) +4 (1) AVERAGE: +3.33
CAP: -2 (1) +2 (1) +3 (1) AVERAGE: +1.00
PAU: +2 (1) AVERAGE: +2.00
PER: +1 (1) +2 (1) +3 (2) AVERAGE: +2.25
SDA: +4 (1) AVERAGE: +4.00
SPO: 0 (1) +1 (1) +2 (5) +3 (6) +4 (7) +5 (2) +6 (1) AVERAGE: +3.17
Bob Lunsford
San Diego, CA USA
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