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(meteorobs) Astronomy magazine's coverage of the 2001 Leonids


>To: meteorobs@atmob.org, astro-l@uwwvax.uwwdot edu
>Cc: imo-news@yahoogroups.com, atmob-discuss@atmob.org, [...]

Just picked up a copy of the November 2001 issue of Astronomy magazine.  
Regarding the information they provide to their readers concerning the 
upcoming Leonid meteor shower, writers Martin Radcliffe and Alister Ling
note the following:

On page 70:

"A fury of falling stars will shoot across the heavens, the likes of which 
have not been witnessed since the 1966 Leonid meteor shower."

    Not exactly true . . . the 1966 shower briefly produced visual hourly 
rates of perhaps 150,000.  At their best in 2001, the Leonid predicted rates 
a full order of magnitude lower (~15,000/hr).  

"The storm surge is expected to hit at night for Australasia and reserve a 
good squall for the Western Hemisphere a few hours later."

    Wrong! The Western Hemisphere is anticipated to see enhanced Leonid 
activity before the Far East.  Peak activity for the Western Hemisphere is 
due near, or soon after 10 h UT on November 18, while Australasia should see 
their outburst roughly eight hours later.

"Meteor counts are likely to range from a couple of hundred per hour over the 
Americas to a few thousand per hour on the other side of the world."

    Even the most conservative estimates indicate hourly rates of at least 
1000/hr. over the Americas, with anywhere from 5000 to 15,000/hr. possible 
for parts of Asia and Australia.  This statement also contradicts what was 
written in the first paragraph ("A fury of falling stars will shoot across 
the heavens, the likes of which have not been witnessed since the 1966 Leonid 
meteor shower").  How can one initially draw comparisons to such a stupendous 
display as the 1966 Leonids by later suggesting hourly rates of ". . . a 
couple of hundred to a few thousand" for the 2001 Leonids?

On page 78:

"A pair of astronomers from the Armagh Observatory in Northern Ireland 
correctly predicted the great Leonid meteor show in 1999 and the lack of a 
great display in 2000."

    While their names are nowhere mentioned in the Astronomy article, this is 
no doubt an allusion to David Asher and Rob McNaught.  However, while Asher 
is indeed affiliated with Armagh Observatory,  McNaught resides in Australia 
and is affiliated with the Australian National Observatory and Siding Spring 
Observatory.

"The storm, if it does occur, will result from Earth passing through streams 
of locally dense meteoric debris during the early hours of November 18.  The 
two streams were deposited along the orbit of the parent comet Swift-Tuttle 
in 1699 and 1866."

    Actually, the storm resulting from these two dust trails will be 
available only from eastern Asia and Australia . . . and since these regions 
are to the west of the International Date Line, the correct time of encounter 
should be ". . . during the early hours of November 19."

"Because meteor shower prediction is in its infancy, the potential for 
disappointment is considerable." 

    This almost sounds like something that was written in advance a 1960s 
Leonid shower.  In sharp contrast, recent predictions of meteor outbursts 
using the new dust-trail methodology (pioneered in Russia and later refined 
by reputable meteor scientists in other parts of the world) have proven to be 
very reliable in anticipating unusually high activity and even more accurate 
in predicted times of such outbursts.

"The best advice is to keep a careful watch on the skies from midnight until 
dawn on November 18."

    No . . . the BEST advice (at least for readers in North America) would 
have been for Astronomy to indicate to their readers the predicted time when 
the encounter with the 1767 dust trail was predicted to take place (near or 
soon after 10 h UT on November 18).  

    Unfortunately, because their readership was not provided with this very 
important piece of information.  I can envision many neophyte observers 
dutifully heading out at the stroke of midnight, yet ironically calling it a 
night after an hour or two in the cold only because they weren't seeing the 
hoped-for meteor storm . . . only to wake up later that morning to hear that 
the anticipated "good squall" did indeed occurred but only after they had 
reacquainted themselves with their nice warm beds!

Joe Rao


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