[NLRS] Leonids meteor shower(s !)

[Baker, Donn B]

The following is from: Science@NASA
<http://science.nasa.gov/headlines/y2003/10oct_doubleleonids.htm>

Obviously, the images were dropped. (Nothing exciting, anyway.)
The first one (13th Nov) isn't interesting, either... too far to our west.

73 Donn
WA2VOI/0

The 2003 Leonid Meteor Shower 

An unusual double Leonid meteor shower is going to peak next month over
parts of Asia and North America.

 Listen to this story via streaming audio
<http://science.nasa.gov/headlines/y2003/images/doubleleonids/audio/story.m3
u>, 
a downloadable file
<http://science.nasa.gov/headlines/y2003/images/doubleleonids/audio/story.mp
3>, 
or get help <http://science.nasa.gov/info/audio.htm>.  

October 10, 2003: The Leonid meteor shower is coming. Twice. Bill Cooke of
the Space Environments Group at the NASA Marshall Space Flight Center
explains: "Normally there's just one Leonid meteor shower each year, but
this year we're going to have two: one on Nov. 13th and another on Nov.
19th." Both are caused by comet Tempel-Tuttle, which swings through the
inner solar system every 33 years. With each visit the comet leaves behind a
trail of dusty debris--the stuff of meteor showers. Lots of the comet's old
dusty trails litter the mid-November part of Earth's orbit. 

"Our planet glides through the debris zone every year," says Cooke. "It's
like a minefield. Sometimes we hit a dust trail, sometimes we don't." Direct
hits can spark a meteor storm, which is defined as more than 1000 shooting
stars per hour. "That's what happened in, for example, 1966 and 2001," says
Cooke. "Those were great years for Leonids." "This year we're going to brush
past two of the trails--no direct hits," he says. Even so, "we might have a
nice display." 

The first shower is expected on Nov. 13th around 17:17 UT. For about three
hours centered on that time Earth will be close to some dust shed by
Tempel-Tuttle in the year 1499. Sky watchers in Alaska, Hawaii and along the
Pacific rim of Asia are favored. They'll see anywhere from a few to 40
meteors per hour--"if they can avoid the glare from that night's gibbous
Moon," cautions Cooke. A good strategy for moonlit meteor observing: travel
to high altitudes where the air is clear or stand in the shade of a tall
building or hillside. 

Leonid meteor rates for selected cities: Nov. 13-14, 2003 	
City	            Local Time	           Maximum number of Leonids in 15
min.	
Los Angeles, CA	5:15 a.m. (Nov. 13th)	< 3		
Seattle, WA	      5:45 a.m. (Nov. 13th)	3		
Fairbanks, AK	7:00 a.m. (Nov. 13th)	10		
Honolulu, HI	5:30 a.m. (Nov. 13th)	9		
Tahiti	      5:00 a.m. (Nov. 13th)	6		
Tokyo, Japan	2:30 a.m. (Nov. 14th)	18		
Christchurch,
   New Zealand	3:30 a.m. (Nov. 14th)	1		
Sydney, 
   Australia	3:30 a.m. (Nov. 14th)	9		
Hong Kong	      2:00 a.m. (Nov. 14th)	8		
Beijing, China	1:45 a.m. (Nov. 14th)	10		
Manila, 
  the Philippines	1:45 a.m. (Nov. 14th)	9		

Table notes: Values listed in the 3rd column are the maximum number of
meteors an observer with perfectly clear dark skies might see in a 15-minute
interval around the shower's peak.

Curiously, the Moon will be much closer to the 1499 trail than Earth will
be. "If the Moon had an atmosphere to catch the comet dust, there would be
about 1400 meteors per hour in lunar skies--a real storm," notes Cooke.
Instead, the Leonids will simply hit the ground.

Most Leonid meteoroids are microscopic, and when they hit the Moon they do
little more than raise a puff of moon dust. But a few will be bigger: the
size of golf balls or grapefruits. Traveling about 160,000 mph, these
impactors can cause explosions visible from Earth. (For more information
about this, read the Science@NASA story Explosions on the Moon
<http://science.nasa.gov/headlines/y2001/ast30nov_1.htm>.)
 <http://science.nasa.gov/headlines/y2001/ast30nov_1.htm>
 <http://science.nasa.gov/headlines/y2001/ast30nov_1.htm>

"This year we won't be able to see any lunar impacts," notes Cooke, "because
most of the Leonids will strike the far side of the Moon. Some will hit the
Earth-facing side, but the ground where they hit will be sunlit. That makes
it very hard to see the explosions."

The second and more impressive shower arrives almost a week later on Nov.
19th when Earth approaches a trail shed in 1533. "Sky watchers up and down
the US east coast will have the best view," says Cooke. "For a while around
07:28 UT (2:28 a.m. EST), they could see more than one meteor per minute."
The Moon, a thin crescent on Nov. 19th, won't be bright enough to interfere
with the display. (Nor will it be close to the cometary dust stream, so once
again there will be no visible lunar explosions.)

Leonid meteor rates for selected cities: Nov. 19, 2003 
City	        Local Time            Maximum number of Leonids in 15 min.

New York, NY  2:30 a.m. (Nov. 19th)	17		
Miami, FL	  2:30 a.m. (Nov. 19th)	14		
Chicago, IL	  1:30 a.m. (Nov. 19th)	13		
Dallas, TX	  1:45 a.m. (Nov. 19th)	9		
Denver, CO	  0:45 a.m. (Nov. 19th)	7		
Los Angeles, 
  CA          0:00 a.m. (Nov. 19th)	3		
Caracas, 
  Venezuela	  3:30 a.m. (Nov. 19th)	17		
San Juan, 
  Puerto Rico 3:30 a.m. (Nov. 19th)	18		
Bermuda	  3:30 a.m. (Nov. 19th)	19		
London, 
  England     5:45 a.m. (Nov. 19th)	7		
Paris, 
  France      6:30 a.m. (Nov. 19th)	6		

Cooke assembled these forecasts using data from several researchers who have
done a good job predicting Leonid storms in recent years: Peter Jenniskens
at NASA's Ames Research Center, Jeremie Vaubaillon of the Institut de
Mecanique Celeste et de Calcul des Ephemerides in France, and Esko Lyytinen.
They mostly agree that Earth will encounter dust streams on Nov. 13th and
19th, but there is less consensus about how intense the resulting showers
will be. Lyytinen, for instance, predicts a maximum of just 30 meteors per
hour on Nov. 19th. Vaubaillon says 100.

Who's right? See for yourself. Be outside when the time comes, looking up.