(meteorobs) am i going to miss them??

[Skywayinc at aol.com]

In a message dated 11/14/2006 2:12:30 P.M. Eastern Standard Time,  
arlene.carol at gmail.com writes:

I see a  lot of increased predictions for this year's Leonids...and the
possibility  of a 'surprise' rate of 100 per hour!

It seems to me that this wasn't  predicted even as recently as 6 months ago,
but I could  be
wrong.

Okay...I have a question ... from what I'm reading, the  highest count of
meteors will occur
in the US. Is that true? In 1998,  the year I joined Meteorbs after watching
a spectacular (for me)
Leonids  shower/storm here, I was surprised to read that others in the US
didn't  have rates as high as mine (i could only count 40/min and i wasn't
watching  the whole sky).
That being the case, and stretching the chance for optimism  for this year...
will I be able to see 100 per hour over here or is it a  sure thing that I'm
out of range?

And even if you suggest I go out  and watch anyway...which night and at what
time  please.



Hi Arlene! --
 
The upcoming Leonid peak was first predicted back in 1999 by David  Asher and 
Rob McNaught.  In a paper published in the meteor journal WGN,  they pointed 
out that a dust trail shed by comet 55P/Tempel-Tuttle back in 1932  would 
likely interact with Earth in 2006.  More recently, calculations by  Esko Lyytinen 
and Jeremie Vaubaillion have pretty much corroborated Asher and  McNaught's 
1999 findings.
 
We actually passed through this trail back in 1969 and it produced a  
half-hour outburst of about 240 meteors per hour for parts of the eastern  US.  It is 
now ready to interact with us again, but the meteor intensity  is not 
expected to be as strong because the parent comet is now about twice  as far away 
from us (in terms of time) as it was in 1969.  So the activity  is not expected 
to exceed 120 per hour.
 
Another caveat is that when the meteoroids were ejected from the comet back  
in 1932, their ejection velocities were unusually high.  This  generally 
corresponds to very small particles, which in turn tend to produce  rather faint 
meteors. Indeed, in 1969, having been a witness of that  particular display, I 
can tell you that about 90 percent of the meteors  that I saw were short, dim 
streaks.  There were a few very bright meteors  of negative magnitude that left 
some smoky trains for several seconds (and  had a rather vivid aquamarine 
tinge), but the "lion's share" of meteors  (pun intended) were rather faint.  I 
suspect that will be the case this  weekend.
 
As for who will be in the best position to see this brief burst of activity  
-- not likely to last more than half an hour -- western sections of Europe and 
 Africa are favored because Leo will be very high in the south-southeast sky 
when  the peak is due (at 4:45 UT on Sunday morning).  That's also just before 
 dawn breaks for these locations, so the sky will still be dark.  From the  
Northeastern U.S., it is a different story.  The Leonid radiant will  be only 
about 10-degrees (or less) above the horizon at the peak time  (11:45 p.m. EST, 
late Saturday night), so even if the 120/hr. meteor rate is  attained, that 
will be significantly reduced thanks to the low altitude of the  radiant.  What 
folks in the Northeastern US should hope to see are a few  long-trailed 
Earth-grazing meteors, skimming out of the east-northeast part of  the sky.  
Indeed, seeing just one of these types of meteors will make an  entire evening of 
meteor watching worthwhile.
 
Lastly Arlene. . . I am sorry to say that your part of the world will be in  
daylight when the peak arrives.  I suspect that you'll probably see a few  
Leonids on Sunday morning, but unfortunately, the main bevy of activity  
generated by the 1932 dust trail will probably wait until after the Sun  rises from 
your location.  
 
Clear skies!
    -- joe rao