[AZ-Observing] Leonids Viewing Strategies



I have written an article for the November TAAA newsletter, but as the
subject has come up I thought I would post the article here a little
early to help with everyone's planning for this year's Leonids...

---- snip ----

Leonids 2002 - Your Last Chance

If you have looked on the internet, in this month's Sky&Tel or Astronomy
magazines, or many other places the Leonids buzz has started again.  No
wonder, after last year's spectacular show of thousands of fireballs
from a true meteor storm.  But will there be a repeat?

The predictions say yes!  All teams (Jenniskens, Asher/McNaught and
Lyytinen/Van Flandern) that called the timing of the peaks perfectly
last year are again publishing predictions for 2002.  Their predictions
for last year may have been a little over exuberant about the numbers,
but the timings of both predicted peaks were correct.  They are again
predicting two peaks for 2002, one at 4h UT and one at 10.5h UT on the
morning of the 19th.  The 4h UT peak will target Europe while we are
still in late evening hours.  But the 10.5h UT peak will be perfectly
placed for viewing from most of North America occurring at 3:30am MST as
the earth passes through debris left by comet Tempel-Tuttle in 1866. At
that time the radiant will be well up in the morning sky, about 50
degrees elevation at an azimuth of about 90 degrees, or almost due east.

To add to the urgency is the predictions that these will be the last
good appearances of the Leonids for several cycles, probably your last
chance for a meteor storm in your lifetime.  The problem for 2002 is a
full moon, not just near full, but almost perfectly full for the second
peak with 99.5% of the face illuminated.  Nature can be perverse that way.

Two tactics of moon avoidance present themselves.  One is to find a
mountaintop to sit upon where the amount of atmospheric aerosols and
dust overhead that moonlight can reflect from is minimized, leaving the
valley dust below you.  Another is to get into the shadow of a mountain
where the moon will set early, blocking direct moonlight and the
mountain's shadow will block moonlight from reflecting from dust in the
air above you.  While the full moon will be up it will also be low on
the western horizon, at the peak it will be only 35 degrees elevation at
an azimuth of 266.  This will only improve for the last hours of the
night as the radiant climbs higher in the sky.

Personally I like my mountain shadow idea.  The moon is setting almost
due west so find a spot due east of the highest convenient peak.  This
places the radiant high in the eastern sky, with the mountains at your
back. For Tucson the best available peaks are Mt. Lemmon (9157ft in the
Santa Catalina Mts.) or Mt Wrightson (9453ft in the Santa Rita Mts.). 
Both offer dark sites with little to no lights visible on the horizon. 
The shadows of the Santa Ritas are somewhat more accessible from highway
83 and several side roads are available to choose from that lead up into
the national forest land.  For Phoenix the Bradshaw Mts. are convenient,
the east slope is easily accessible from I-17 and they are quite high
(7108ft), so maybe somewhere above Bumble Bee is the place to be.

You will probably find me in the shadow of Mt. Wrightson with a lounge
chair and camera gear on the morning of the 19th!

Andrew


For more info...

http://comets.amsmeteors.org/meteors/showers/leonidprediction.html
http://leonid.arc.nasa.gov/


-- 

Andrew Cooper
Tucson, AZ
mailto:acooper@xxxxxxxxx
http://whitethorn.house.home.att.net
--
See message header for info on list archives or unsubscribing, and please 
send personal replies to the author, not the list.

Other related posts: