From: Joe Rao 
Date: Sun, 19 Nov 2000 19:46:11 EST


   I finally got an opportunity on Sunday to sit down and listen to my taped
observations of the Leonid Meteor Shower of Friday night/Saturday morning.  I
observed from my in-laws ranch house at Brodheadsville, Pennsylvania
(southern Monroe County in the Pocono Mountains).  The local weather was
quite variable from sunset up until about 1 a.m. EST/Saturday morning, as sky
conditions ranged from perfectly clear to completely overcast with occasional
very light snow.  It was obvious that lake-effect snow showers emanating from
Lake Ontario were being blown southeast across central New York State and
into northeast Pennsylvania.  I was not overly concerned, however, because
local forecasts had high pressure, diminishing winds and a strong area of
subsiding air that was projected to build into the region as the night
progressed, which inevitably should squelch the clouds and any flurry
activity.  Sure enough, from 1 a.m. to 4 a.m., the sky was almost always
perfectly clear, with just some occasional periods of scattered clouds . . .
mostly staying to our west and north.

    Considering the bright moonlight, conditions were not at all bad.  Only
about 30 percent of my sky was obscured . . . mostly to my northeast and
east.  My limiting magnitude was estimated at +5.1.  Locally, the temperature
hovered at 28 degrees F. Thank goodness there wasn't much of a wind!

    The Leonids put on a very good showing this year.  The typical Leonid
appeared as a swift streak of 0 to +1 magnitude and whitish in coloration.
If brighter than 0, it usually left a brief train in its wake.  The brightest
Leonids appeared to have an aquamarine hue.

    As can be seen below, I observed a total of 137 meteors with a teff
(total viewing time) of 120 minutes.  Of the 137 meteors, 125 were Leonids
(L) and 12 were sporadic (S).  While the overall numbers suggest an average
observed hourly rate for the Leonids of 62.5,  it is readily apparent from
the numbers below that they were most active between 1:22 and 1:54 a.m., when
observed raw Leonid rates were closer to 88 per hour.

    None of these 15-minute counts were corrected to Zenithal Hourly Rates,
nor was any rate adjustments made to account for the bright Last Quarter
Moon.  Mr. John E. Bortle, a longtime contributing editor to Sky & Telescope
magazine observed the Leonids from his home in Stormville, New York (Dutchess
County) and came up with hourly rates very similar to mine.  Mr. Bortle did
covert his raw counts into ZHR obtaining corrected rates in the 120-130
range.  However .  . . he also stated that no correction factor for strong
moonlight was applied, which ". . . likely would have make the actual ZHR
2x-3x higher!

    Interestingly . . . at 1:24 a.m., I saw three Leonids in very quick
succession, namely within a span of just 1.5 seconds!  The first two actually
appeared within a half second of each other . . . the second appearing to
nearly parallel the Hyades just as the first, to the west of Orion,
disappeared.  A second later, the third quickly streaked across  Perseus.  It
was quite striking to see all three move along tracks parallel to each other.
 (a "cheap thrill" to briefly see meteors however-so-briefly coming at a rate
of 120/minute)!

    There were two other times (in the 1:39 to 1:54 a.m. interval) when I hit
a "spurt" of 3 Leonids within a less than 10 second interval, including my
best Leonid of the night -- a beauty that shot through the lower portion of
Canis Major, low in the sky toward the south-southeast.  It approached Venus
in brightness and left a trail that I could follow in binoculars for a full
minute.

    At 1:55 a.m., I went inside to "rouse the troops" (my wife, two kids and
in-laws).  Only my father-in-law decided to stay in his warm bed.  The others
scurried outside to waiting lawn chairs and sleeping bags.  My 10-year old
son, Joseph, and my 7-year old daughter, Maria, were especially pleased at
being able to see the Leonids since I had dragged them across the Atlantic to
Lanzarote (in the Canary Islands) last year only to see a shower -- of rain!


    I had hoped that those brief bursts of high activity would be a precursor
to a grand display at around 2:51 a.m. -- the time that was predicted to the
peak for our interaction with debris shed by Comet Tempel-Tuttle back in
1866.  However, it appears . . . at least from my tally below . . . that this
year's peak came about 60 to 90 minutes earlier than expected.  In fact,
there was a noticeable diminution of activity immediately after 2:51 a.m.  So
noticeable was the decline in activity, that my wife and kids and my
mother-in-law decided to pack it in just before 3:30 a.m.  I took some time
out to say good night, get warmed-up and drink some hot chocolate.  I went
outside for another 15-minute session, but decided to call it a night at 3:55
a.m. as a new batch of clouds from the northwest rapidly swept in.

EST/Nov. 18       Observed Activity
------------------       -------------------------
1:05-1:20                14L   1S
1:22-1:37                22L   0S  INCLUDES 3 WITHIN 1.5 SECONDS @ 1:24!
1:39-1:54                22L   3S  Best of night @ 1:43 a.m.  Low SSE in
"triangle"
                                   (Aludra/Wesen/Adhara) of Canis Major.
Magnitude
                                   -3 to -4; left 30 second trail to eye; 1
min. in
                                   binoculars.

1:55-2:15   Break to "rouse the troops!"
2:17-2:32                 20L   1S
2:34-2:49                 19L   3S
2:51-3:06                 13L   1S
3:08-3:23                 10L   2S
3:24-3:39   Said goodnight to the troops . . . went inside to warm up;
                 drank hot chocolate
3:40-3:55                   5L   1S

NORTH AMERICA'S PROSPECTS FOR NEXT YEAR:  There are again predictions for
multiple Leonid peaks in 2001.  During November 18 and 19, the Earth is
predicted to interact with several different trails of dust ejected by Comet
Tempel-Tuttle from the years 1666, 1699, 1799 and 1833.  Highest activity is
expected over eastern Asia and Australia soon after 18:00 UT on November 18,
where some forecasts are suggesting rates of up to 15,000/hr!

    For North America, the one encounter that seems to yield the greatest
promise for high activity is the 7-revolution dust trail (shed in 1767).
There are three specific predictions for this trail that have been published
. . . all of which are very close in both the predicted peak times and
predicted hourly rates:

1) David Asher (Ireland) and Robert McNaught (Australia) are predicting an
hourly rate of 2500(?) on November 18 at 10:01 UT  (5:01 a.m. EST/2:01 a.m.
PST).

2) Esko Lyytinen (Finland) and Tom Van Flandern (USA) are predicting an
hourly rate of 2000 on November 18 at 09:58 UT (4:58 a.m. EST/1:58 a.m. PST).


3) William J. Cooke, Jr. (NASA/USA) and Peter Brown (Canada) are predicting
an hourly rate of 2250 on November 18 at 10:01 UT (5:01 a.m. EST/2:01 a.m.
PST).

    The Moon will be a thin waxing crescent, only 3 days past new and long
gone by the time the Leonids will be reaching their maximum.  Thus, sky
conditions will be dark and viewing conditions excellent.  It is hoped that
with the 2000 Leonids now behind us, the new data will allow projections for
2001 to be recalculated, or a better model developed.  As McNaught and Asher
noted in the April 1999 WGN, it is possible that " . . . before the potential
storms of 2001 the predictions could be very well defined."

What else can I say?
See you all next year!