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(meteorobs) Re: various Leonid notes
From Bob Young :
>Would the Moon's physically blocking of meteors (those striking the Moon) have
>an effect here in cutting down the rate?
The moon is about 108 times its own diameter away from the Earth. Think how
effective an umbrella would be if located 108 times its own diameter above
your head in a heavy rain with no wind. Jupiter at the same distance (its
surface or center) as the moon should be big enough to block all the Leonids.
From Felix Martinez :
>Did anyone else notice how nicely active the Taurids were on 17/18 Nov?
Not me. I saw 3 Taurids the first hour, then none thereafter. Not
surprising in this off-year for Taurids. Over the past 30 years I have
noticed the Taurids are best in years ending in 1, 4, 7, and 8. Good rates
and most of the fireballs concentrate in such years. In the other years
Taurids can be dismal. In 1974 I went to 21 Taurids (N and S not separated)
plus 4 sporadics in the hour 1128 - 1228 EST on Nov 11/12 in sky LM 7.0.
There were 2 major fireballs in 1988 : on Nov 6/7 at 132 EST, a blue -10m
North Taurid with train 30 seconds ; then Nov 9/10 at 202 EST a blue-green
-12m North Taurid with train 40 seconds. Much of the sky turned blue during
both fireballs which were located fortuitously not far from the zenith.
Mike Linnolt had what he thought was an enhancement of sporadics. The night
of 1975 June 17/18 produced some remarkable rates. Three hours 228 - 528
EDT in sky LM 7.0, totals 13,17,29. The last hour had 2 June Lyrids with
twilight cutting LM to 6.0 at the end. Sporadics were blasting in all over
the place with no impression of any active radiants. I have to attribute it
to a lucky spin on the random number generator. A generation later I am
still waiting for something similar to happen again. That was one of my
most unusual experiences ever.
The recent UPDATE virus looked suspicious to me right away. It did not
appear to serve any purpose so I dumped it on the spot.
From Henry, concerning Janne visiting from Finland and observing in Florida :
>Why isn't this woman out counting votes?
Janne has a Y-chromosome. Oops. One of the ambiguous names (Kim is
another.) I had a roommate at Florida State named Jan, also a Y.
I made up a color table for my 2000 Leonids. It is just an exercise since
there is no variation in color among the showers. The only minor exception
is a few green ones appear during the Geminids, but the basic color pattern
is still there. Breaking down the colors by magnitudes makes it independent
of sky conditions, even using a couple of casual Leonids, plus color
perception can be quantified. I start losing color at magnitude +2m. An
overall color percentage is meaningless so I don't include one.
Each row contains one magnitude of Leonid meteors with the total yellow,
orange, blue, sum of the first 3 colors, total Leonids seen, and percentage
colored of that magnitude.
-3m : 0,1,1 ; 2,2,100%
-2m : 2,1,1 ; 4,4,100%
-1m : 11,4,6 ; 21,21,100%
0m : 21,2,3 ; 26,26,100%
+1m : 14,0,13 ; 27,27,100%
+2m : 3,0,2 ; 5,40,12.5%
+3m : 1,0,0 ; 1,27,3.7%
+4m : 0,0,0 ; 0.35.0.0%
+5m : 0,0,0 ; 0,21,0.0%
In addition, there was a tricolored -5m : white-blue-green. The colors are
given in order of intensity. Blue-white is not the same as white-blue, for
example. Joan didn't see a single colored meteor, not even the -3m we both
saw that I called intense orange. A lot of people see all their meteors as
just white. Among those that do see color, probably no two will have the
same overall pattern.
One correction on Nov 17/18 data. Time interval 701 - 706 UT I saw 9
Leonids, not 7.
Norman
Norman W. McLeod III
Staff Advisor
American Meteor Society
Fort Myers, Florida
nmcleod@peganet.com
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