The Leonids 1999
Fine Display in 1999!
The first reports from Europe about observations of this year's Leonid meteors were received at ESO, just before 5 hrs MET (4 hrs UT). They indicated moderately intensive activity, with the maximum at about the time predicted (2 hrs UT). The peak may accordingly have been at about 15-20 meteors/min, possibly even higher. Despite clouds in most places, the observers were delighted!
Later reports from sites with clearer views contained higher numbers, up to 50-60 meteors/min. This corresponds to a major shower.
The following brief report summarises the event. It was published on November 18 on IAU Circular 7311 by the IAU Central Bureau for Astronomical Telegrams (CBAT): A pronounced peak in Leonid meteor activity occurred for about an hour centered on about Nov. 18d02h05m UT, agreeing very closely with predictions by Asher (1999, MNRAS 307, 919) and McNaught and Asher (1999, WGN 27, 85), which in turn suggest that the observed activity represents debris ejected from comet 55P/Tempel-Tuttle three revolutions ago. G. M. Hurst, Basingstoke, England, forwards a report from J. Mason that observations by members of the British Astronomical Association located north of Sharm El Sheikh, Egypt, revealed as many as 50 Leonids/min for a few minutes around the peak. Numerous other visual reports from observers in Jordan, Israel, Spain, and Portugal give similar results, as do data from radar monitoring by P. Pridal and R. Stork (Ondrejov) and radio monitoring by K. Suzuki (Toyokawa, Japan) and C. Steyaert (Mol, Belgium).
More information has become available on IAU Circular 7313, issued on November 20: A rather broad second peak in this year's Leonid display appears to have occurred around Nov. 18.6-18.9 UT, in which visual counts of 100-300 meteors/hr were reported by observers in Hawaii (S. J. O'Meara), Japan (K. Mameda, Y. Kushida, R. Kushida, T. Kagawa; communicated via S. Nakano), and China (Rui Qi; communicated via J. Zhu).
Interesting details about Leonids at the Moon (observed as vediorecorded flashes) are reported by D. W. Durham on IAU Circular 7320, issued on November 26.
See also the extensive reports now available from observing sites in Jordan (Jordanian Astronomical Society (JAS) and D. Fischer ), as well as the summary about radar observations.
More information is available at the sites linked from further down this page. Note in particular the detailed technical report from the International Meteor Organisation (IMO).
Below are excerpts from some of the reports received at ESO soon after the event (note that they represent the opinions of the authors!). Together they provide a kaleidoscopic view of a great event, a deep and personal experience for most involved.
(Latest Update of this page: November 29, 07:30 UT)
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From Bernard Pellequer (Aniane Observatory, France): Summary of our observations :
3 people observing, partially cloudy with a strong wind.
Universal Time
0h00 - 1h00 20 environ (approx.)
1h10 - 1h20 20
1h22 - 1h32 33
1h35 - 1h45 68
1h55 - 2h05 90
2h05 - 2h15 140
2h14 - 2h24 73 (two people observing at this time
and more clouds -a very bright meteor
during this period)
2h26 - 2h36 103
2h39 - 2h49 90
2h59 - 3h09 36
It was a fantastic night !!
Frédéric DAUDE
Lionel VELTZ
Bernard PELLEQUER
Geospace Observatoire d'Aniane
43deg 41' North
03deg 36' East
From Robert Wielinga (Utrecht, The Netherlands):
From 02.57 to 03.15 (MET - ed. note) we (team from the Public Observatory Sonnenborgh in Utrecht) observed hundreds of Leonids in a sky that was partly clouded! Sometimes in only a few seconds we saw several meteors, some of them seems to appear simultaneously! Most were between magnitude 2 and 0, only a few fainter meteors were seen. The brightest meteors were magnitude -4. Some color was seen, mostly green. We think in this short period about 20 meteors per minute were vissible, the real number must have been much higher since we missed a lot (especially the fainter ones) because of the partly clouded sky. It was a great show!! But alike the eclipse it was much too short! Robert Wielinga From a group of Italian students: We prepared observations from Torino and from Bologna: in Torino we had very good weather conditions, in Bologna not so good. We observed from about 3h10m until about 4h30m; the maximum was at the beginning of our observation, direction south and we observed about 5 meteors each minute for the first half hour of observation, then the phenomenon was decreasing. Cold but interesting night! Cristina Palici di Suni and Angela Turricchia From Felipe E. Mac-Auliffe (La Silla, Chile): I was watching the Leonids from La Silla during all the night. The meteor shower wasn't so impressive from here, despite the great weather conditions. I counted 10 bright ones (Mv ~ 0) and a lot of faint ones. The average rate was about 20 meteors per hour. I took several pictures using my Canon camera mounted on one of the equatorial mounts that are located in the "Sarcofago", together with an 11-inch Celestron telescope. I'm going down the mountain today and, the first thing that I am going to do is to stop by the photo lab and develop the film to see what came out... From Jay Pasachoff (Williams College, USA): I observed from the shore of the Mediterranean at El Saler, south of Valencia, Spain, with my wife, Naomi, and daughter Deborah. We saw Leonids at the rate of 12 a minute, or 720 per hour, for much of the time in the crucial half hour centered on about the predicted time of 2:08 UT (3:08 local time). Sometimes meteors would come one per second. Few fireballs appeared, but sometimes meteors appeared simultaneously in double, almost parallel streaks across Orion, as the radiant in Leo continued to rise in the eastern sky over the sea. We saw a magnificent shower, by far the best I have ever seen, but not quite the meteor storm that was at the top of our hopes. It began about an hour before the predicted maximum, and few meteors had been visible earlier in the evening. From Luis Paulo Carrasqueiro (Centre for Astrophysics, Porto, Portugal): The Leonids over here were my first real meteor storm. They weren't extremely bright (the maximum I saw was mag = -2, but a friend who stayed up longer saw what was a probably a -7). The peak was reached as expected at 2 am and our basic statistics indicates around 750 - 800 per hour. There weren't bright fireworks, but a lot of faint ones, a *lot*. From Anders Vaesterberg (EAAE, Stockholm, Sweden): 18 students from two of our astronomy classes at Saltsjoebadens Samskola (2nd year, 17 years old) and I observed the Leonids from the Stockholm Observatory (59N 18E). Most of the time the sky was entirely covered by clouds and sometimes it was even raining, but between about 2:30 local time and 2:45 (Central European Time, which is UT + 1 hour) most of the sky was clear, and we could see meteors at a rate corresponding to about 200 per hour. About half of them were of magnitude 0 or brighter, often with smoky trails. Around 3:00 we saw about 5 meteors/minute but then most of the sky was cloudy. Now the meteors showed more colours, mostly green. Taking the light pollution and the clouds into account, the rates should be much higher. This was a thrilling and beautiful experience for all of us. A few meteors were really marvellous with long trails. We agreed that if we had seen only one of these, it would still have been worth the effort to stay up so long in the cloudy, chilly and sometimes rainy night. Our tiredness vanished completely when the clouds started to spread and this celestial display became visible to us. From the "Parsec-Astrorama" Club (Nice, France): Last night, about 40 person were waiting for this astronomical phenomenon. It began at 1h30 (local time). At this moment few Leonids were visible. At 3h we could easily estimate that 1 000 - 1 200 Leonids per hour were visible in the sky. Beautiful !!!! From the CDEPA-Astronomical Observatory (Tavira, Algarve, Portugal): Observations commenced 23.00 UT 17th of November. Leonid activity low,
Taurids observed at ZHR approx 10.
24.00 UT Leonid activity still low, Taurid and sporadic rates
increasing slowly.
01.00 UT 18 November first earth grazing Leonids Mag -2 , 60: long trails,
rates increasing rapidly.
01.30 UT a Leonid every 10 seconds now.
02.00 UT PEAK! more than one Leonid per second now!, furious activity.
Working with 10 cameras clicking and 2 television crews here.
Sky conditions excelent, Mag +6. No Wind, No Dew.
Looking forward to next year!!!
Clive Jackson
From Francisco Jose Bellido (Agrupacion Astronomica Mizar, Montilla, Spain): I observed the Leonids with 15 students of an Astronomy class at Instituto Inca Garcilaso in Montilla (South of Spain). We started at 23:30 UT and finished at 3:30 UT. This was an impressive storm. By far the best I have seen in all these years as a stargazer. We counted more than 40 meteorites per minute. There weren't many bright fallen stars but many of them appeared in pairs. I was astonished by the incredible green colour of some meteors trails. From Raul Lima (Porto, Portugal): The observations reported below were done in Sande, Marco de Canaveses, Portugal (about 41.05 N, 8.1 W, 40+ km E from Porto) with cloudless skies, an almost clear horizon at East (exception made for a nice-when-there-are-no-leonids-meteor-showers tree... but without leaves, thankfully...), clear at South and West, clear above 10 degrees at North and partially blocked at Northwest. The magnitude limit after 1h30 UT was about 6.1 at 40 degrees from the horizon (East and North), and a little below that value in the other directions. Starting our observation at about 0.0 UT, we saw very few meteors until about 1.0 UT (but during the first half hour the moon was still above the horizon); after 1:00 UT there was a notorious crescendo - about 600 meteors/hour between 1h35 and 1h45 UT - with a peak between 2:00 UT and 2:20 UT of above 750 meteors/hour. Many faint meteors and few fireballs (one of them with fragmentation, in south Monoceros). Around the peak several (3, 4, five and even 6, once) simultaneous, making it difficult to count, sometimes. After 2h30 UT there was an also notorious decrease, with a slight peak between 3h00 and 3h05 (not counted; maybe 5-6/ minute), when a short but very bright fireball was seen, around magnitude -7. That fireball started another show until about 4h45, where some -3 and -4 fireballs (one orange but generally white-green) were seen, near Leo, among some swift and long magnitude 1 and 2 meteors. The rate had then decreased to about 2-3/minute. The observation ended at 5h10 UT. Until about 3H00 UT, the observations were made with Cristina Dordio, Luis Paulo Carrasqueiro, Filipe Pires and Elsa. From Barbara von Arb, Philipp Heck (Zurich, Switzerland): Date: 1999 November 18 UT
Observing Period: 1h00m - 3h20m UT
Observing Location/Site: Dalpe (Southern Alps, Ticino, Switzerland)
Geographic: Lon: 8d36m Lat: +46d31m
Very bright Leonid fireball!
Time: 1999 Nov 18, 1h45m UT
Estimated visual magnitude: -14 to -16
much brighter than full moon, bright illumination of landscape
Position: roughly between Regulus and M44 (~ RA 9h20, Dec +15=B0)
Color: first green then orange
Trace: trace was visible for about 10 minutes after fireball disappeared
and extended from a straight line from 5-10 degrees length =
into a horseshoe-like and then into a doughnut-like 'nebula' of =
about 25 degrees in diameter.
Leonid meteor counts
Period: 1999 Nov 18, 1h48m - 2h03m (Effective Observing Time: 15 min)
Field Centre: RA 9h30m, Dec +15deg with no obstruction
Limiting magnitude: ~6 mag
Counts: 228 leonid meteors, no sporadics (during 15 min)
Magnitude range: -4 to +4 mag
From "Philippus Lansbergen" Observatory (Middelburg, The Netherlands): 3 members of our observatory made their observations from "Cyclops"
observatory in Oostkapelle, Holland. It was a most enjoyable night!
We started at 00.00hrs, but there were a lot of clouds. At around
01.00hrs we started counting meteors by video-tape. On tape we have
243 Leonids!
Between 01.00 - 01.15hrs 5 leonids
01.15 - 01.30hrs 5 leonids
01.30 - 01.45hrs 20 leonids
01.45 - 02.00hrs 48 leonids
02.00 - 02.15hrs 80 leonids
02.15 - 02.30hrs 67 leonids
02.30 - 02.45hrs 22 leonids
Note: The Leonids mentioned were counted only in that part of the sky
that was covered by our Video-camera!
At 02.01 we counted 6 leonids per/minute
At 02.02 we counted 8 leonids per/minute
At 02.03 we counted 12 leonids per/minute
At 02.04 we counted 4 leonids per minute
The maximum was exactly at 02.03hrs. At 02.45 we stopped counting
because of the clouds. The Area we observed by Video was in the east:
Gemini, Orion, Taurus, Auriga. We were lucky that during the maximum
there were almost no clouds in this part of the sky.
We were probably the only people in the Netherlands who registered by
Video.
Rijk-Jan Koppejan
From the Sirius Astronomical Society of Kermanshah (Iran): There was a quite pleasant mild cold, clear sky last night and the members of the Society observed the shower all night. The rate was about 15 per hour at early hours (from 2:00 in local time to 5:00 am, i.e. from 11:30 pm to 1:00 am UT). Thereafter, the number grows to 60-100/hr and from 5:25 to 5:45 am (1:55 to 2:15 am UT). Suddenly the rate rose to 25-30 meteors /min (1500-1800/hr). They were very fast and their magnitudes were from -4.5 to +2 with a white to yellow color. We had the best view of observing in Iran as our city is in the far west of the country at longitude 47 deg 5 min east; latitude 34 deg 19 min north; altitude of 1200 m. above the sea level. M.A.Khodayari (M.D.) From Olivier Vallejo (Bordeaux, France): November the 18 of 1999 will be engraved for ever on my memory, punctuating a year rich in celestial emotion (solar eclipse). We are on Wednesday, the 17, in Montelimar, south-east of France, the sky becomes overcast, and the hope to see the Leonid meteor shower becomes gradually blurred. A friend of mine phones me, telling me that southward the sky was better, without hesitation we have to go to best horizons. At 30 km, south-east of Montelimar, the show was about to begin, under a fantastic sky with no luminous pollution. On the road to the observation place, like a good omen, we saw some fireball in the Big Dipper. At 0h30 UT we arrived and began to settle down on the floor comfortably, without thinking of what we were going to see. One of my friends, a specialist of shooting stars, took his tape recorder to record the number of shooting stars, with the constellation name and the magnitude of each one, like we have done a few months ago with the Perseid meteor shower. According to some astronomical reviews, they announced in France, between 500 and 600 meteors per hour during the maximum peak, number close to what we saw for the Perseid meteor shower last summer. But, one hour before the theoric maximum, this number was smashed, we counted about 2000 meteors in the first half hour. Sometimes a fireball split the sky, giving rise to a collective shout of joy, until the Lion really begun to roar, taking out its sharp claws, lacerating all the constellations. The show must begin! It was 1h30 UT when the cosmic symphony begun, the crescendi were exceptional and the vision was magical. No sound, just a little freezing breath of air coming from the North, we lay down, and, keeping our eyes wide opened, we savoured with a great emotion the beautifull fireworks the sky gave us. The Earth had just crashed headlong into the remnants of the comet Temple Tuttle. About ten arrows covered my field of view per second, paralysing me, like pinned to the ground by a mystery force. According to my estimates, the ZHR was about 30000 during the maximum peak, from 2h15 UT to 2h50 UT. I had a special thought to those who did not see such a show. The apotheosis, the firework finishing, occured when a huge fireball dazzled us during some seconds, leaving a trace in the sky 15 degrees long, 30 minutes wide. From Babak A. Tafreshi (Editor at Nojum - Astronomy magazine of Iran): A NIGHT TO REMEMBER - WHAT A SHOWER! From old times, people believed when they see a meteor they can make a wish. But in the Morning of Nov. 18, we rand out of wishes! Our site was about 200km south of Tehran, 60km away from any light, on the roof of an ancient place called the Palace of Bahram, in the middle of the desert. Close to 1:50am UT on Nov.18, the ZHR reached the highest level of 2500. It seems that we missed the highest peak at 1:55 AM with ZHR of 3500 because of morning light. We started sky watching the night before (Nov. 16/17). No great Leonid was seen, but a few woo-making Geminid fireballs! On the night of Nov. 17, nothing happened until 2.30 AM day after. The ZHR increased very fast and the peak was sharp. The sky above us was not crystal-clear but a bit hazy. Most of the meteors were white with magnitude 1-4, altough there were also dazzling fireballs in Ursa Major and Orion (magnitude -4 to -9). The best picture we have recieved up to now got 20 and a green point in the radiant. The amazing point of the shower was that every 5 to 10 minutes or so we had a couple of great meteors all over the sky and then it cooled down until another peak. It seems that this year's Leonid stream had many narrow parallel bands. Another point was a peculiarity of the radiant. It was not very well focused, very vast in a few degrees. We can call this year's shower a Baby Storm, but still not comparable to last year's background stream with those unforgettable fireballs over the lovely lands of Iran. From Pavol Rapavy (Observatory Rimavska Sobota, Slovakia): The expedition in which participated 12 observers (November 12-22)
was organized by Observatory Rimavska Sobota.
Observing site coordinates: 36.8 N, 2.07 W
(Los Escullos-San Jose, near Almeria, Spain)
Program: - visual observation (tape recorder, voice, resp.
light clock)
- photographic observation (stationary camera and
parallactic drive mounting)
- TV CCD camera
- CCD camera SBIG ST-8 (objective 2.8/20,
paral. drive mounting)
- photographing a spectrum of meteor trains
Preliminary visual report (for standard population index 2.5).
November 18, 1999, clear and dark sky (5.7-6.0 mag). A maximum ZHR
7000-8000 in sol. long. 235.290 (2000.0) =3D 2:08 UT. The activity in
the range of 235.278 to 235.302 (01:51 - 02:26UT) was higher than
ZHR 5000.
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Good Prospects for the Leonids 1999
It is expected that the Leonid meteor shower will produce good displays in November 1999 as well as in the next years. Various predictions have been published in the past, but meteor watchers awaiting the Leonid shower in November 1998 were taken by surprise when a spectacular display of bright meteors occurred 16 hours before the predicted time for the maximum of the shower, see the Leonids 1998 webpage at ESO. In the meantime, explanations for this discrepancy have been put forward by various researchers who, at the same time, now venture to provide improved predictions.
The following text is extracted from a recent Press Release by the UK Royal Astronomical Society (30 August 1999; 459-pn97-12-nam ) and contains very useful information about the coming Leonid event. Further details may be found via the weblinks available below.
"The latest analysis, covering Leonid meteor storms over the past two hundred years, shows that the peak times of the strongest storms and sharpest outbursts are predictable to within about five minutes. The technique involves mapping the fine `braided' structure of the dense dust trails within the Leonid meteoroid stream. Although comet Tempel-Tuttle, the 'parent' of the Leonid stream, passed close to the Earth in 1998, Drs. David Asher (Armagh Observatory) and Rob McNaught (Australian National University) predict strong meteor storms in both 2001 and 2002. 1999 and 2000 will be less spectacular, but good. In 1999, observers at European longitudes are favoured, and may see up to 20 meteors a minute (in ideal conditions under a clear, dark sky) at around 2 a.m. (UT) on the morning of November 18th."
"Meteors, popularly known as 'shooting stars', can be seen on any night, given a sufficiently clear, dark sky. They are produced by the impact on the Earth's atmosphere of small dust grains released from comets. Most meteors arrive in 'showers' at fixed times of the year, when the Earth passes close to the orbit of the parent comet. But occasionally - just a few times a century - a phenomenon known as a meteor storm occurs. During a storm, meteors appear at astonishing rates, sometimes several per second. The most famous example, the incredible Leonid display of 1833, is credited with starting the serious scientific study of meteors."
Links
Additional information may be found at these major Leonid sites on the web:
- The comprehensive, more general Meteors' webpage of the popular astronomy journal Sky & Telescope at http://www.skyandtelescope.com/observing/objects/meteors
- The ESO/EAAE Astronomy On-Line programme (1996) included a major sub-project about the Leonids. See:
http://www.eso.org/public//outreach/eduoff/aol/market/collaboration/meteor/ - The Armagh Observatory Leonid website contains much detailed information about the prospects for observations.
- Reports from observers from all over the world will be updated every 15 minutes at the website of the Aerospace Corp.