(meteorobs) December 12, 2004 Meteor Observations from California

[Robert Lunsford]

I observed from the Deerhorn Valley Helipad tonight, a site some fifteen
miles south of Descanso. I was accompanied by veteran observer Joseph and
his friend from Washington DC, Chris. We watched for six hours under totally
clear skies. There was a shallow marine layer along the coast but it was not
thick enough to block any of the city lights. Therefore there was a large
light dome in the west. Geminid activity was impressive right from the
start. A great majority of the Geminds were of magnitudes +2, +3 and +4. Kim
Youmans was correct in stating that this shower would have been unimpressive
if seen from urban skies. As you can see from the data below, the Geminid
rates were fairly constant during the entire night. The highlight of the
night was a beautiful -8, pure white (at least though my eyes) Geminid
fireball that shot eastward through central Leo. It also left a train of
very short duration. Also impressive were the two long Puppid-Velids that
shot up from the southern horizon. It was on to work after this session and
I was too busy there to listen to my data therefore my Geminid reports will
be a bit tardy.

December  12, 2004

0630-0730 UT   1.00   6.17    2 ANT  0 COM  33 GEM  0 HYD  0 MON
                                                0 PUP   4 SPO  39 TOTAL

0730-0830 UT   1.00   6.26    1 ANT  0 COM  34 GEM  1 HYD  0 MON
                                                1 PUP   5  SPO  42 TOTAL

0830-0930 UT   1.00   6.27    0 ANT  1 COM  32 GEM  1 HYD  0 MON
                                                0 PUP   11  SPO  45 TOTAL

0930-1030 UT   1.00   6.29    1 ANT  1 COM  32 GEM  0 HYD  0 MON
                                                0 PUP   5 SPO  39 TOTAL

1030-1130 UT   1.00   6.42    2 ANT  3 COM  40 GEM  2 HYD  2 MON
                                               0 PUP   6  SPO  55 TOTAL

1130-1230 UT   1.00   6.56    0 ANT  0 COM  34 GEM  1 HYD  0 MON
                                               1 PUP   12 SPO  48 TOTAL

TOTALS:           6.00   6.33    6 ANT  5 COM  205 GEM  5 HYD
                                               2 MON  2 PUP   43 SPO
                                               268 TOTAL METEORS

The first column gives the period watched in Universal Time (UT)
which is PST + 8 hours. The second column gives the percent of that
particular hour actually spent observing the sky (1.00 = 100%, 0.99
= 99%). Time is lost for breaks and plotting. I was recording data on a
cassette recorder tonight so each hour was a full sixty minutes of
observing. No breaks other were taken as I was able to take the
recorder with me as I occasionally stood up and stretched. The third
column gives the average limiting magnitude estimated during each
period. The last several columns list the activity for expected active
radiants during each period. Quite often no activity is observed and
rates equal zero. Tonight I was facing south with my field of view
centered at 50 degrees altitude. ANT = Antihelion radiant (Xi Orionids),
COM = Coma Berenicids, GEM = Geminids, HYD = Sigma Hydrids,
MON = Monocerotids, PUP = Puppid/Velids and SPO = Sporadics
(random activity).

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

Bortle Scale Estimate: Class 3: Rural Sky

Beginning Temperature/Relative Humidity: 50 F (10 C) 60%
Ending              "               "             "        49 F (9 C) 59%

MAGNITUDES OF INDIVIDUAL METEORS PER RADIANT:

ANT:   0 (0) +1 (2) +2 (0) +3 (1) +4 (2) +5 (1)    AVG: +3.00
COM  0 (1) +1 (0) +2 (0) +3 (1) +4 (3) +5 (0)    AVG: +3.00
GEM:  -8 (1) -4 (1) -3 (2) -2 (3) -1 (6) 0 (7)
+1 (27) +2 (38) +3 (54) +4 (44) +5 (21) +6 (1)   AVG: +2.55
HYD:  0 (1) +1 (0) +2 (0) +3 (1) +4 (2) +5 (1)    AVG: +3.20
MON: 0 (1) +1 (0) +2 (0) +3 (1) +4 (0) +5 (0)    AVG: +1.50
PUP:   0 (0) +1 (0) +2 (1) +3 (1) +4 (0) +5 (0)    AVG: +2.50
SPO: -4 (1) -3 (1) -2 (0) -1 (0) 0 (2) +1 (0)
         +2 (3) +3 (17) +4 (16) +5 (8) +6 (0)          AVG: +3.23

Bob Lunsford
San Diego, CA USA