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(meteorobs) Jan. 3 Meteor Observations From the Mojave Desert
Tuesday dawned in the desert without a cloud in sight. Wouldn't you know
it though that cirrus began appearing on the northern horizon at noon.
By 3pm thin cirrus streaked through most of the northern half of the
sky. At sunset the clouds had made their presence known in all areas of
the sky. The southeast was the least effected with the northeast the
most. Under these conditions it was still possible to conduct an
observing session as the clouds were moving rapidly and there was always
an area that was unaffected. It was a colorful sunset but as I entered
the tent for some sleep I just hoped it got no worse.
When I awoke at 1130pm the sky was apparently clear. I say apparently
because some very thin cirrus had to be present since the LM's of +7.0,
seen the previous morning, were reduced to the mid 6's. Yet stars were
visible down to the horizon in all directions. The moon was low in the
west creating a nice scene. It was gone by the time I began recording at
midnight.
The first hour was fairly active with 16 meteors being recorded. The
first Quad was not seen until 00:55am. 3 more quickly followed before
the end of the hour.
The second hour was just a bit more active than the first. There was a
dip in the sporadic rate offset by the increase in Quad activity.
The third hour was much like the second with slightly elevated Quad
rates and 7 sporadics.
The fourth hour saw a steep increase of both Quads and sporadics. It was
during this hour that I received the call from Kim Youmans. Right before
he called I had seen 17 Quads in 15 minutes. There were also 7 non-Quads
seen seen during that period so my estimate of one meteor every 45
seconds at that time was not far off. Unfortunately these rates did not
continue and the Quad rates for that hour ended up at only 50. I know it
sounds crazy to have 20 sporadics an hour but these meteors were
definitely not Quads. It will be interesting to see Dave Holman's
results from this time if he was still awake!
The fifth hour saw only a slight increase of Quad rates when it should
have been a large increase. It was obvious now that the Quads were
either exhibiting a weak return or that the maximum rates were to occur
a few hours later. The sporadic rate fell by more than half and the
resulting hourly total was less than the previous hour.
The last hour had a DECREASE in Quad rates. The actual ZHR most likely
increased since I lost a half magnitude due to twilight. The sporadic
count rebounded to 14 leaving my hourly totals 2 shy of the previous
hour.
After talking to Kim and reading the Japanese and Chinese accounts it
seems to me that the Quads peaked a bit later than expected. It is a
shame that Mike Linnolt was clouded out in Hawaii as he could have
confirmed this. Perhaps either Mike Morrow or Jim Bedient can confirm
this.
All in all it was a nice trip. It ended too quickly but David had been
there since Sunday so I cannot blame him for leaving Wednesday. The
Quads were disappointing but it was a good start to 2001. I would have
stayed had I known that the conditions at home were so bad with the
smoke filled skies from the large brush fire to the east. My new voice
activated cassette recorder worked like a charm. I kept nice and warm
and let the machine do all the work! I also shot a roll of 36 exposures
which I will have developed soon. The camera was on a driven equatorial
mount only a foot off the ground so all I had to do was reach over from
the lawn chair and advance the film without using much effort at all.
January 3, 2001
0800-0900 UT 1.00 6.58 1 COM 1 DCA 4 QUA 10 SPO 16 TOTAL
0900-1000 UT 1.00 6.61 1 C0M 1 DCA 12 QUA 6 SPO 20 TOTAL
1000-1100 UT 1.00 6.59 1 COM 0 DCA 16 QUA 7 SPO 24 TOTAL
1100-1200 UT 1.00 6.56 3 COM 1 DCA 50 QUA 20 SPO 74 TOTAL
1200-1300 UT 1.00 6.47 3 COM 0 DCA 58 QUA 8 SPO 69 TOTAL
1300-1400 UT 1.00 6.03 2 COM 0 DCA 51 QUA 14 SPO 67 TOTAL
TOTALS: 6.00 6.47 11 COM 3 DCA 191 QUA 65 SPO 270 TOTAL
The first column gives the period watched stated in Universal Time (UT)
which is PST + 8 hours. The second column gives the percent of that
particular hour actually spent observing the sky. The third column gives
the average limiting magnitude of my field of view estimated during each
period. The last several columns lists the activity seen during each
period. I was facing northeast at an altitude of 50 degrees during the
entire session. No breaks were taken.
COM = Coma Berenicids (Northern Apex Radiant), DCA = Delta Cancrids
(Antihelion Radiant), QUA = Quadrantids, and SPO = Sporadics
(random activity).
Beginning Temperature/Relative Humidity: 42 F (6 C) 15%
Ending " " " 36 F (2 C) 14%
MAGNITUDES:
COM: -2(0) -1(1) 0(0) +1(0) +2(4) +3(2) +4(3) +5(1) +6(0) AVERAGE:+2.73
DCA: -2(0) -1(0) 0(0) +1(0) +2(0) +3(2) +4(0) +5(1) +6(0) AVERAGE:+3.67
QUA: -2(1) -1(6) 0(22)+1(23)+2(38)+3(36)+4(40)+5(21)+6(4) AVERAGE:+2.55
SPO: -2(0) -1(2) 0(5) +1(10)+2(9) +3(12)+4(17)+5(7) +6(3) AVERAGE:+2.83
Bob Lunsford
San Diego, CA USA
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