From: Peter Brown, University of Western Ontario, London, CA
 (observing from Edwards AFB, California)
Date: Nov. 18, 1997

Radar observations at Edwards AFB, California

The night of Leonid maximum was clear from Edwards AFB in California.
Our team ran an HF radar operating at 20 and 30 Mhz for the entire shower
period (it is still operating) as well as two Electro - optical sites with a total of
10 cameras.
The early evening of Nov 16/17 saw some small increase in the normal visual
rates, this being given away by a few bright Leonid meteors with the radiant
still almost on the horizon. The activity slowly increased through the night,
but began rising significantly around 11:15 UT Nov 17. Based on some 15
minute counts to this point, the ZHR (with an LM of 5.0 - 5.5) was roughly
60 (from 10:30 - 11:15 UT). The rates started rising significantly after this
point, with a peak of roughly 1-2 Leonids per minute from 12-12:15 UT. In
very approximate terms, the ZHR for this interval (12-12:15 UT) would have
been in the neighborhood of 200 +- 50, but this is very approximate given the
moonlight. The heightened activity was most noticeable in the large number
of fireballs visible from the Leonids from our site, including a -9 Leonid and
several -8, -7s and a multitude of fainter (< -6) Leonids. The activity
noticeably decreased after 12:15 UT, despite darker skies (as the moon
started to get lower) and a higher radiant. By the end of useable observing at
13:30 UT, the ZHR had dropped down to roughly 100 and was still
decreasing. We did see several brighter fireballs in the bluish predawn sky
attesting to some continuation of the display.
The TV systems showed an increase in the number of fainter meteors
detected in the same region of time as the visual peak, but only about a factor
of 3 higher than in the early post-midnight hour. The HF radar system showed
a large number of very persistent echoes (some as great as 5 minutes) and
many in coincidence with visually/TV observer meteors.
Qualitatively there seemed to be a preponderance of bright Leonids, but
whether this is intrinsic to the stream in 1997 or simply an artifact of the
moonlight is not easily determined from our visual observations.