FreeLists / az-observing / [AZ-Observing] Leonids from NW Arizona -- ZHR 3000+ (!)

[Wil Milan <wmilan@xxxxxxxxxxxxxx>]

My family and a couple of friends left Phoenix at 6pm and headed northwest, 
determined to drive as far as it would take to get into the clear skies 
behind the band of moisture passing through Arizona. We finally broke into 
clear skies southeast of Kingman, setting up around 10pm at a small plateau 
just west of the Burro Creek Wilderness.

 From this site we had essentially clear skies all night long except for a 
few fleeting cirrus and some low haze near the horizon. For us "The Big 
Show" began at about 1:30am when I started seeing a meteor every few 
seconds. I woke the others and we watched as it waned, only to pick up 
again after 2am.

By 3am (right on schedule!) the pace was racing, with meteors raining down 
in every direction, several in the air at a time. They were coming down so 
quickly in every direction that it was impossible to see them all. A couple 
of us remarked that it was no longer necessary to try to find them; no 
matter what direction one looked, one or two (or more) meteors would appear 
there within seconds.

The pace continued essentially unabated for more than an hour, and after 
some discussion about estimating a rate, at 4:10am we took an organized 
1-minute count with 5 people counting (one facing each quadrant to the 
horizon, one counting straight up). Our 1-minute count was 54 meteors, 
indicating a ZHR of 3240 per hour (!!!). That was a short sample, but the 
rate of meteors we were seeing during that period did not seem appreciably 
different from what we'd been seeing for most of the previous hour, and it 
continued afterward for some time.

The high hourly rate seemed to be confirmed by a digital time-lapse camera 
that was recording a patch of sky 36 x 53 degrees, approximately 9.3% of 
the visible sky. The camera was recording a frame for 43 seconds out of 
each minute, shooting a new frame each minute, and during the peak period 
the camera very often saw 3 - 4 meteors in those 43 seconds, a rate of 
roughly 4 to 5.3 meteors per minute, which works out to a rate of 44 to 57 
per minute for the whole sky, indicating ZHRs of roughly 2600 to 3400. The 
time-lapse camera took over 300 frames and some of them had as many 6 
meteors per frame, indicating that brief peaks may have been even higher, 
and I noted from direct comparison that the camera did not see the faintest 
meteors, so the true visual rate was certainly higher than whatever the 
camera recorded directly. (The digital images have not yet been processed; 
the processing may bring out meteors that were not evident during the 
acquisition.) In any case, the assembled video footage from this camera 
promises to be spectacular.

The camera also caught an amazing event: The brightest Leonid fireball of 
the night happened to occur directly in the field of view of the time-lapse 
camera, and for most of the next hour the camera recorded the slow dimming, 
drift and disintegration of its vapor trail, slowly twisting and stretching 
in direct view of the camera the whole time. I've never seen a video 
sequence of something like that -- could it be a first? Maybe not, but it 
would be nice to think so. :-)

All in all we had a terrific time, saw something that may well be once in 
lifetime and, I hope, recorded some unique events and amazing sights. What 
more could one ask of a single night?

Wil Milan
http://www.astrophotographer.com/
"The heavens declare the glory of God
And the firmament proclaims His handiwork."
   -- Psalm 19:1

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