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Our Leonids
2002 Expedition to Andalusia, Spain
In November 2001, the
Leonids put on a truly spectacular display. Although
there was not a ‘storm’ with meteors falling
down like rain, the shower did rain meteors and
fireballs for many hours, providing the best meteor
shower activity I have ever seen. I made an
expedition to Braeside Observatory in Flagstaff,
Arizona to observe the event, and secured a maximum
ZHR value of 1426 (full results here) under very
good sky conditions.
Leonids
2001 : the lion roars over Australia. Image (c) Massimo
Russo, Italy
Composite of 3 exposures of 15 min each,
obtained on
2001, Nov 17/18, using a 19-mm f/1.8
objective and Fuji 400 film. |
2002 will be another
impressive Leonids year, according to the latest predictions
of meteor scientists. Last year clearly
demonstrated that prediction models are maturing to
a stage where the time of maximum activity can be
relatively well forecasted. However, large
discrepancies still exist with respect to the
expected peak rates. For 2002, the different models
seem to be in much better agreement, both in terms
of time of maximum activity and peak rates. Overall,
we can expect to observe ZHR values of 3500 meteors per hour (up to
6000) in the night of November 18/19th,
2002. Unfortunately, moonlight will seriously hamper
observations, the lunar phase being nearly full, and
will significantly reduce the effective number of
meteors visible to the naked eye. Nevertheless, we
are ready for another Leonids expedition, a bit
closer to home than in 2001.
Predictions
for 2002
In 2002, Earth will travel through the dust
ejected by Comet 55P/Temple-Tuttle in 1767 and in
1866.
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The passage through the 1767 dust trail will be
visible from Europe, while the 1866 event is
visible from the Americas only.
Note that Earth will also pass the 1965 dust
trail on November 17th, but the predicted peak
rates are
very low.
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(c)
Armagh
Observatory, College Hill, Northern
Ireland |
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Let's review the predictions now in detail. The table
below provides an up to date summary, listing Leonids
2002 forecasts from leading meteor scientists.
For Europe, all forecasts more or less put maximum
shower activity around 4h UT in the morning of November
19, 2002, with ZHR peak values ranging from
1.000 to 5.900 meteors. By far the best forecasts of
Leonid outbursts during the past three years have
been those issued by Esko Lyytinen, and therefore
his data will serve as our best guide to how strong
the Leonids will become in 2002 and when peak
activity is to be expected.
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E.
Lyytinen |
P.
Jenniskens |
McNaught-Asher |
J.
Vaubaillon |
Optimal
for |
1767
dust trail |
Nov.19
04:03UT
ZHR 3.500
FWHM 1.76hr |
Nov.19
03:48UT
ZHR 5.900
FWHM 0.64hr |
Nov.19
03:56UT
ZHR 1.000
FWHM 2.17hr |
Nov.19
04:04UT
ZHR 3.400
FWHM 2hr |
North-Africa
West-Europe |
1866
dust trail |
Nov.19
10:40UT
ZHR 2.600
FWHM 2.03hr |
Nov.19
10:23UT
ZHR 5.400
FWHM 0.60hr |
Nov.19
10:34UT
ZHR 6.000
FWHM 1.18hr |
Nov.19
10:47UT
ZHR 3.000
FWHM 3hr |
North-America |
The figure at
right is a graphical wrap-up of the Leonids
forecasts for 2002. Note that the nearly full
moon will make observing conditions the worst
possible : for every magnitude lost due to
moonlight, the actual number of meteors is cut
by roughly 60%. With a limiting magnitude of
4.0, one will see only 1/10th the meteors one
would see if it were 6.5. |
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(c)
Hiroshi
Ogawa,
Japan |
Preparing Our
2002 Expedition
Taking
into account the fact that peak activity of the 1767
and 1866 dust trails is expected to yield nearly
identical ZHR values over Europe (1767 trail) and
the US (1866 trail), we found no evident reasons
justifying a trip to the US. On the contrary, Europe
is offering very good viewing conditions in terms of
total numbers of meteors visible.
The
excellent map at right (by Hiroshi Ogawa)
plots expected total number of meteors (based
on Lyytinen's predictions), taking into
account altitude of radiant, moonlight and
twilight interference, etc. |
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(c)
Hiroshi
Ogawa,
Japan |
The
map illustrates that North Africa and West Europe
have best observing prospects. As there's only
marginal differences in terms of observable amounts
of meteors between both continents, I decided in
favour of Europe.
Major
problem, however, is that November is
synonymous to unstable, rainy weather in large parts
of West Europe. Luckily, there’s some regions, most
notably in the southern part of Europe, that are
widely known for excellent weather conditions, even
in November. So, we studied a “cloud cover map”,
indicating mean November cloud cover at night, that
was provided by meteorologist Jay Anderson.
When
combining the “cloud cover map” of Anderson with
the Ogawa map of “total numbers of visible meteors map”, it is evident that the southern part of Spain is a
quite favourable location for observing the Leonids.
Since I'm familiar with this part of Spain, from
earlier holiday trips, the whole process of
identifying a spot for observing the 2002
return of the Leonids, was rather straightforward
this year.
The
two figures below provide some further, detailed
information. At left is another map by Ogawa,
indicating total number of expected meteors over
Spain during the night of maximum activity. The
figure at right shows that, at the moment that Earth
encounters the 1767 dust trail, morning twilight
will be approaching Spain. However, it is still at a
safe distance, even if there would be a relatively
large error in the time predictions of peak
activity.
Observing the
Leonids from Andalusia, Spain
So, I selected Spain as
my target destination, and
more precisely the Andalusia region (most
southern part of Spain). Last
step in the selection process now was to identify a
proper location for my observing session. Since
I wanted to stay far away from coastal villages
(light pollution, air moisture), I had to look for
small villages in the Andalusian interiors, yet
providing decent lodging capabilities.
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I finally
identified a tranquil rural retreat,
situated
in the "heart of Andalusia", with
magnificent all-round views, close to the white village of
Alora (pictured at left). Alora is only
a 45 minutes' drive from Spain's Malaga
airport, and the whole area is rich in natural
monuments, offering excellent sight seeing
opportunities during daylight. |
I will be visiting Alora from
November 16th till November 19th, and I intend to
make visual as well as photographic observations of
the Leonids, with the specific objective of
accurately determining ZHR levels over the course of
the nights.
Photographic
observations will be particularly challenging
due to interference of strong moonlight. I
expect to limit exposure times to 5 minutes
(on a 400 ASA film) and to set the diafragma
stop at 4.0 or so.
The sky map at right shows the night sky above
Alora, Spain at the moment of peak activity of
the Leonids, on November 19th 2002 at 04h UT
in the morning.
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Meteors and
Gargantas
One excursion I'm
planning to undertake in Andalusia, is to hike the Garganta
del Chorro - El Chorro Gorge. Close to Alora,
the Rio Guadalhorce river carves its way through the
awesome El Chorro gorge, up to 400m deep, and in
places as little as 10m wide. The gorge, about 4 km
long, is traversed not only by the main railway in
and out of Málaga (with the aid of 12 tunnels and
six bridges) but also by a footpath, the Camino
del Rey, which for long stretches becomes a
perilously decaying concrete catwalk clinging to the
side of the gorge up to 100 m above the river.
The camino has been in a
state of alarming disrepair for years and has been
officially closed since 1992 but adventurous folk
with a head for heights are still using parts of it.
Exactly what I
plan to do ... weather permitting.
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(c) http://inlandnwclimb.homestead.com/files/xcamino.jpg |
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Copyright ©
2002 - Tonny Vanmunster.
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