(meteorobs) October 21, 2004 Meteor Observations from California

Robert Lunsford lunro.imo.usa at cox.net
Sat Oct 30 15:01:42 EDT 2004


I drove to the Trona Pinnacles National Monument to observe the Orionid
meteor shower. This location is twenty miles east of the small town of
Ridgecrest. I had used this site before to view the 2003 Leonids. The site
is amazingly dark considering the proximity to Los Angeles. I was planning
to leave a day earlier but heavy rain made observing on October 20
impossible. It was still raining heavily as I left San Diego near noon on
Wednesday. It rained most of the way north. I arrived shortly before sunset
and was met by fellow observer Robin Gray, who had driven down from
Winnemucca, Nevada. It was still sprinkling and the prospects did not look
good for that night. After a quick meal we made a campfire to keep warm. As
the evening progressed the sky began to look more promising. We retired and
woke at 1145 local time under a beautiful, clear sky. We began counting at
midnight and continued until 6:00am. Orionid rates were fairly impressive
the entire session. There was a peak between 2 and 3am when Orionid rates
reached 20 per hour. The rates slowly declined the next two hours then
surged to 23 the last hour. The anthelion rates (Taurids) were low but
steady most of the night. The Epsilon Geminids were only seen during the
second half of the session. The Leo Minorids were present with rates of one
per hour during the last two hours of the night. Apex meteors were less
active than expected. Sporadic rates were near what I expected. Robin and I
were both amazed that mosquitoes were so numerous at such cool temperatures.
The occasional breeze from the southwest did not seem to deter them either.
At least their constant buzzing helped to keep us alert.

October  21, 2004

0700-0800 UT  1.00  6.60   2 ANT   11 ORI  0 EGE  0 LMI
                                             0 NPX   0 SPX  2 SPO  15 TOTAL

0800-0900 UT  1.00  6.63   2 ANT   13 ORI  0 EGE  0 LMI
                                             0 NPX   0 SPX  5 SPO  20 TOTAL

0900-1000 UT  1.00  6.64   3 ANT   20 ORI  0 EGE  0 LMI
                                             0 NPX   0 SPX  8 SPO  31 TOTAL

1000-1100 UT  1.00  6.52   2 ANT   16 ORI  1 EGE  0 LMI
                                             0 NPX   1 SPX  10 SPO  30 TOTAL

1100-1200 UT  0.92  6.46   0 ANT   14 ORI  0 EGE  1 LMI
                                             1 NPX   2 SPX  10 SPO  28 TOTAL

1200-1300 UT  1.00  6.45    2 ANT   23  ORI  3 EGE  1 LMI
                                             0 NPX   0 SPX  8 SPO  37 TOTAL

TOTALS:          5.92  6.55   11 ANT   97  ORI  4 EGE  2 LMI
                                             1 NPX   3 SPX  43 SPO  161

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
southeast at an altitude of 50 degrees during the entire session. One five
minute break was taken.  ANT = Antihelion radiant, ORI = Orionids,
EGE = Epsilon Geminids, LMI = Leo Minorids, NPX = Northern
Apex, SPX =  Southern Apex and SPO = Sporadics (random activity).

Location: Trona Pinnacles 117 22" 32" W  35 06' 03" N

Bortle Scale Estimate: Class I (Truly Dark Sky)

Beginning Temperature/Relative Humidity: 47 F (8 C) 74%
Ending              "               "             "        42 F (6 C) 95%

MAGNITUDES:

ANT:  -1 (1) 0 (0)  +1 (2) +2 (4) +3 (2) +4 (2) +5 (0)   AVE: +2.09
ORI :  -3 (1) -2 (2) -1 (5) 0  (6) +1 (16) +2 (17)           AVE: +2.24
          +3 (26) +4 (19) +5 (5) +6 (0)
EGE:  0 (1) +1 (1) +2 (0) +3 (1) +4 (0) +5 (1) +6 (0)   AVE: +2.25
LMI:  0 (0) +1 (0) +2 (2) +3 (0) +4 (0) +5 (0) +6 (0)   AVE: +2.00
NPX:  0 (0) +1 (0) +2 (1) +3 (0) +4 (0) +5 (0) +6 (0)  AVE: +2.00
SPX:  0 (0) +1 (0) +2 (1) +3 (2) +4 (0) +5 (0) +6 (0)   AVE: +2.67
SPO: -1 (2) 0 (0) +1 (3) +2 (4) +3 (9) +4 (18) +5 (6)   AVE: +3.35
          +6 (1)

Bob Lunsford
San Diego, CA USA



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