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(meteorobs) Gary's Leonid MAC observations (Prelim)
Some of the 1999 Leonid MAC observations have been published elsewhere, but
I do want to give an idea of what we saw during the mission.
First, our unofficial test of the equipment came on the morning of November
14. We did a complete set up of the equipment once both aircraft were above
10,000 feet. Our maximum altitudes on that morning were less than 30,000
feet. For my group, we determined the field of views of the light
intensified cameras and practiced trying to quickly identify the star
fields each camera was pointing at. The limiting magnitude of the camera I
primarily used was about 9. I was detecting about 5 Leonids per hour, with
the majority around magnitude 5 and 6. The highlight of that night was that
we obtained great footage of the aurora borealis while we were over the
North Atlantic. The next day Peter Jenniskens gave a hi-8 camera to me and
asked that I find and mark the times meteors traveled through the aurora. I
found two after a fairly short period of time, one dead center in the field
which was definitely a Leonid. This was my first experience with a bright
aurora.
Second, our mission nights covered the nights of November 16/17, 17/18, and
the morning of the 19th. The computer statistics for each observer are just
beginning to be sent to us. What I have right now is that the 8-person flux
measurement team that I was part of logged a total of 16696 meteors. I
personally logged 2980 meteors during 9.75-hours of actual observing time.
Most of these meteors were obviously seen on the night of maximum. I have
been promised that my totals will be broken down into 10-minute intervals.
I am hoping that the GPS data will also be included so I know where I was
during each interval. On the night of maximum, the pilots reported meteors
were falling as we were increasing our altitude after leaving Tel Aviv.
Just as the seat belt signs were turned off and before the equipment was
set up, all the windows on the right side of ARIA (the plane I was in) lit
up briefly. With more glass in the cockpit, the pilots later told me that
this flash of light lit up the controls around them! I saw numerous meteors
within the range of magnitude 1 and -3 on this night through my camera,
although there were still plenty visible down to magnitude 7. Later review
of the Japanese HD TV tapes revealed several fireballs that left beautiful
persistent trains. There were occasions on the night of maximum when I took
the headset off and looked out my window. The glass was poor by my seat and
although I could easily see Cassiopeia, Polaris, and the Big Dipper, I
doubt the limiting magnitude was better than +4. Nevertheless, with this
wide field before me I made several random 1-minute counts that I placed in
my own notes that were not part of the official data. Within the hour of
1:30-2:30 UT my 1-minute count totals ranged from 11 to 19 meteors. Our
altitude for these nights was usually around 37,000 feet. As we were flying
over the Mediterranean Sea near Greece on the night of maximum, there were
strong storms visible on the Japanese HD TV system. Several sprites were
recorded, lending support to a theory that sprites and meteors might be
related. Our highest ZHR rates, as determined from calculations by Peter
Jenniskens using the data we provided from the six light intensified
cameras, was 2200. Just as twilight began, and shortly before our landing
in the Azores, our totals had declined to a ZHR of about 65. This was the
first time I had ever witnessed a meteor storm and the first time I ever
witnessed sprites.
I hope to provide a more complete look at my totals when the are sent to
me. It might take another week before I have the hard data of what I saw.
Sincerely,
Gary
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