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Fw: Please forward re:(meteorobs) Leonids in Astronomy (fwd)


Re: Astronomy magazine's Leonid coverage:

Thank you Joe Rao for pointing out the error I made in Astronomy magazine
regarding the 2001 Leonid prospects (and Larry Wood for forwarding me the
note). Looking back at the information I had available to me, I can't see
how I managed to switch the timing between western and eastern hemispheres.
It certainly wasn't intentional. Contrary to the opinion of some of my
friends, I guess that means I'm human <grin>. Seriously though, I'll make
sure that corrected information gets onto the Astronomy website.

Mr Rao also argued with several other aspects of the material. When you're
dealing with very limited column space, not every nuance can be made
explicit. As well, I think where we differ are on matters of opinion, as
you will see below. If you want to lobby the editors about the limited
coverage on the topic, please contact them. 

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

You have to love the nuances of language! Here Mr Rao interpreted my
sentence differently than I intended: "the likes of which" refers to the
this year's shower. The last time anyone has encountered several thousand
per hour was in.... 1966 (in ramp up and down from the max). In other
words, we haven't seen the likes of this since 1966. Some of the challenge
with the language is writing in the present tense (for the reader), 6
months before the event, and comparing it to previous events before the
cutrrent event has happened. In my opinion, the comparison is justified. 

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

This was my (not intentional) mistake. Can't explain how I made it in the
first place, let alone didn't catch it while reviewing. All I can do is
fix it on the web, ask Astronomy to print a notice of error, and be more
vigilant in the future.

>> Ling: "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."
> Rao:  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

My original text (edited from the final copy) talked about lower rates from
the city. Also, a keen meteor observer friend of mine was in Europe two
years ago and reported 1/2 the rates of people observing from the same
(dark) hilltop. There will be a wide range of rates reported.

> > Rao: 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?

Because it's the closest (only?) thing that carries any meaning for readers.
Say the name Ikea-Seki to Astronomy readers and chances are less than 5%
will know that it was vastly more impressive than Hale-Bopp. To be absolute,
yes, the comparison to the original was pushing it a bit far, but what else
am I going to compare it to, that has been around in astronomy texts other
than the last two years of Leonid reports in magazines?

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

Seeing that trail prediction hasn't been in practice for more than 5
years, I didn't think that "infancy" was too harsh a word. "Childhood" 
would have been more appropriate though. Coming from a fellow
meteorologist, I find it surprising that a few fairly successful
predictions are enough to convince Mr Rao of high reliability, especially
when there have been several contradictory ones in the last couple of
years. I'm not doubting the success or the methodology, but you can only
model what you know. Perhaps there were unusual outbursts that happened
but were not recorded. These would not be part of the model and would be
unpredicted. 

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

I see this as a matter of opinion. The best advice I can give remains to
stay awake for the whole night, that way it will be impossible to miss
something.  If you trust the predictions that much, AND don't want to stay
up more than two hours, then the best advice is to watch near the
predicted peak. Given the possibility that not everything is
known about the Leonid meteor stream, I personally would not want to
recommend to people to watch only for a couple of hours and have them miss
something interesting. I think in this matter we can agree to disagree.
It's a difference in our approaches! 

Mr Rao notes:  

> 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!

If people don't want to follow my advice, that's their choice. And just as
easily I can imagine their alarm going off at 4 am, taking a peek out
their bathroom window from the city, and
1) upon seeing the show already in progress, be miffed that they listened to
Mr Rao's advice too closely
2) upon not seeing the legion of 2nd-4th magnitude meteors that dark sky
observers are watching, they go back to their bed, still warm, and see
nothing at all!

Readers of this list should consider the variety of advice available and
make a decision that they are comfortable with, factoring in the
predictability of the event, their own habits, interests, and personal
commitments (including having to work during the day on the weekend!).  
Mr. Rao can follow his best advice, but I shall follow mine. 

As I noted at the top, we'll make sure the correct timing information will
soon become available on the Astronomy web site.

Good observing!
Alister Ling.



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