Wat laat komt hier een bericht van de reeds bijna een week geleden teruggekeerde Sino-Dutch Leonid Expedition 1998 uit China. Kort en krachtig: een enorm succes! En daar is helemaal niets teveel aan gezegd.
Wel liep het wat anders als verwacht: het zogenaamde "stormuurtje" in de nacht van 18/19 tussen 17 en 23 UT ging voorbij zonder noemenswaardige verhoging. Daar voor in de plaats kregen we echter de dag ervoor (16/17) een schitterende "regen" van vuurbollen voorgeschoteld die z'n weerga niet kende. Geen van de expeditiedeelnemers heeft zoiets ooit eerder in z'n meteorenloopbaan meegemaakt. Deze nacht is zelfs met superlatieven moeilijk te beschrijven. Vandaar dat nog niemand van de expeditiedeelnemers kans heeft gezien c.q. de moed heeft genomen een en ander onder woorden te brengen.
Momenteel is een ieder hard bezig met het uitwerken van waarnemingen, het ontwikkelen van films en het uitkijken van de videotapes zodat resultaten geleidelijk aan beschikbaar komen. En dat er veel resultaten zijn daar kunnen jullie op rekenen want alle drie nachten rond het maximum 16/17, 17/18 en 18/19 waren op onzer beider lokaties in China glashelder. Ondanks de intense koude (-15 tot -20 graden) is er technisch vrijwel niets fout gegaan zoals zojuist weer werd bewezen aan de hand van een aantal schitterend belichte films die net in bad zijn geweest. Kortom: de uitstekende voorbereiding is niet voor niets geweest!
De expeditie is feitelijk dubbel geslaagd want ook het totale verblijf in China is een ware verademing geweest! Het bleek fantastisch samenwerken met de Chinezen te zijn. Chinezen blijken uiterst vriendelijk en hulpvaardig te zijn en alles te doen om het je naar de zin te maken! China zo'n "moeilijk" land? Vergeet het maar, een goede voorbereiding draagt echter evenzeer haar steentje bij! Ook de 2 dagen site-seeing in en om Beijing waren zeer de moeite waard. Kortom: China? Dat doen we heel graag nog een keertje op deze manier!
Wilt u alles weten over onze resultaten? Kijk dan eens regelmatig op de DMS-webstite
Het is er nu nog tamelijk leeg maar dat zal in de komende weken heel erg gaan veranderen! De foutieve berichtgeving in een deel van de vaderlandse pers zal dan ook snel met hard feitenmateriaal gelogenstraft worden! Nu al zijn er werkelijk schitterende foto's van nalichtende sporen op te bewonderen! Foto's van (simultaan) gefotografeerde meteoren zullen wat later beschikbaar komen alsook filmpjes van met de beeldversterkers gefilmde meteoren waaronder ook een zeer fraai verwaaiend nalichtend spoor!
Casper Ter Kuile,
Sino-Dutch Leonid Expedition 1998
(Dutch Meteor Society).
November 23, 1998
Reports from around the world confirm that the peak of the Leonid meteor shower occurred between 14 and 19 hours earlier that experts had predicted. Observers in Europe and teh middle East saw a rain of meteors averaging 250 per hour between 00:00 and 12:00 UT November 17. The most intense activity, according to the International Meteor Organization (IMO), took place between 00:00 and 03:30 UT when 510 meteors per hour were seen by experienced meteor watchers.
Centre for Research in Earth and Space Technology
Ground observations collected by the Canadian science teams in Ulaan Baator, Mongolia and at Tindal Air Force Base, Australia, revealed a density of roughly 100-200 meteors per hour, posing little threat to Earth's satellite fleet. This number falls many times shy of the Leonids meteor storm of 1966, which coincided with the last trip by parent comet Tempel-Tuttle as part of its normal 33-year orbit around the Sun.
"While it wasn't what we anticipated, it was a great opportunity for our science team to further develop our predictive model," said Richard Worsfold, CRESTech's Leonids project manager, who is with the Australia team at Tindal. "But, it's great news for satellite operators, who now only have to worry for part-B of the storm, which isn't until this time next year."
In superlative terms, this year's Leonids will not go down in history as the first of the modern space age but as one of many showers. However, if "part B" of the storm takes place as predicted next year, as now seems to be the case, all records are still up for grabs.
The 1999 storm, or shower, will be visible on November 17 next year, although this time visible over Europe and the Middle East and will quite definitely be the last opportunity for a major meteor storm for at least another 30 years.
As of the shower's end, no satellites operators had reported anomalies. In all likelihood, these reports will, if applicable, be generated over the next several days or weeks at the discretion of satellite owners.
Generally speaking, a storm requires sightings of at least 1000 meteors per hours, while a shower requires only about 100. Attached is a list of the recent meteor showers for comparison.
The Centre for Research in Earth and Space Technology (CRESTech) is a not-for-profit science and technology organization created to conduct multidisciplinary collaborative research and development in Earth and space sciences. It is based in Toronto, Canada and supported by the Ontario government's Centres of Excellence program.
ROYAL ASTRONOMICAL SOCIETY
18 November 1998 - 1.00 a.m.
Amateur astronomers and member of the public in the UK and other western European countries have been reporting large numbers of meteors - hundreds per hour - between about 1.00 and 6.00 a.m. on the 17th. By noon GMT, the rate seemed to have declined substantially, according to reports from observers in the US, where it was still dark. The peak of the storm probably occurred over the Atlantic Ocean around 6 a.m. GMT.
Astronomer Dr Alan Fitzsimmons of the Queen's University, Belfast, was one of the lucky observers to witness the storm in the clear dark skies over the La Palma Observatory. "The number of bright meteors is astounding" he wrote as the storm grew in intensity at about 5.30 a.m.. "Every couple of minutes you get a bright flash behind you and you turn around to see the trail fading. The brightest meteors have bright green trails, and often bright red heads. We are approaching one meteor per second and the rate still seems to be increasing, but twilight is now beginning."
The precise timing and strength of an exceptional meteor storm such as this is extremely difficult to predict. Astronomers bold enough to make forecasts had suggested the peak was most likely to be seen around 8 p.m. GMT, and any storm best seen from the far east. Once the observations made this year are analysed, it should be easier to predict whether there could be a repeat performance in 1999.
No information has yet been received on whether any satellites or spacecraft suffered damage as a result of the meteor storm.
November 18, 1998
Here are some first reports of the Leonid meteor shower. More will follow later. I observed from 21:30 to 02:00 UTC (November 17/18). Eight bright and orange coloured Leonids were seen, magnitude -2 to -4. So in The Netherlands nothing of a shower was seen in the hours immediately after the predicted outburst event (November 17, 19:45 UTC).
Meteor/Leonid observations for the night of Nov 15/16, 1998 From Descanso, California, San Diego County
I just got back from the best meteor shower I've ever witnessed. I observed from my descanso, calif. observatory under clear skies with bob lunsford. I have a teff of about 7.5 hours and an LM near 6.0 for most of the night. I plotted until about midnight and then just record data without plotting. I recorded a total of 140 meteors. 77 were leonids, 31 N. Taurids, 2 S. Taurids and 30 sporadics. But!! out of the 77 leonids I recorded 25 fireballs. I also recorded a brilliant N. Taurid fireball with a magnitude of -12. I thought that was gonna be the highlight of the night...but it didn't even come close. The magnitudes of the leonid fireballs are as follows:
-3,-3,-3,-3,-3, -4,-4,-4,-4, -5,-5,-5, -6,-6,-6,-6, -7,-7,-7, -8,-8, -10, -12, -12, -15
The trains lasted quite long for a lot of them. One -7 had a train last 30 seconds, then the other two -7's had trains lasting over 100 seconds each, one of the -8's train lasted over 100 seconds as well. The -10 had a train last 4.5 minutes and the -15 train lasted over 8 minutes. The -15 and a -12 had persistent trains that were of magnitudes of around -8 for a few seconds it seemed. They snaked and twisted all over the place. It was hard to keep count of their durations because often another fireball would show up. The -15 occurred above and behind us...the stars totally disappeared and the sky looked like daylight blue for a second or two. It was pure old excitement. I wanted to go to the bathroom, but didn't dare because I was afraid I would miss another fireball. The strange thing about last nights activity, there were very little dim meteors...that is those that were of around +3 or dimmer. Besides the fireballs, I also recorded three that had magnitudes of -2 and 8 were of -1 magnitudes. I won't have time to do my report for a few days...but I bet my mean magnitude will be around -3 or more? Never had this happen before. We were caught completely off guard for this kind of activity the night before the leonid maximum. I hope to be out there again tonight for the leonid maximum...if the weather holds out? Now to get some shut eye...I might have to do a road trip to an area in the desert near Yuma, arizona if that front comes down like it might...got my toes crossed.
No storm but an amazing number of fireballs here in Panama, Central America. We are about 9 degrees North. We saw a couple on our way to the hills outside of the city limits. Once there we say many fireballs but a few meteors. We started counting from 2 AM to 4 AM (same as EST)and it came to 378 and most of them were very bright fireballs ranging from green, orange to bluish. It was incredible. Some of them literally crossed 3/4 of the entire sky before disapearing. 4 of them were so bright that waked up some friends taht were sleeping. I haven't sleep since 10:30 last night and right now it's 12:30 PM and I'm working in the office. I will go home for some sleep and develop last night's film. Unfortunately, only after 1 roll of film is that I noticed that the lens was all dewed up. But i believe that I managed to get some nice pictures. Let's see. But it was amazing. By the time we left at 4:45 the count was at a total of 455. I might go out tonight and get better pictures if there are any of the Leonids left. The limiting magnitude should be around 4.5 The milky way was wonderful.
Chun In Martinez
Driving on the Edinburgh city bypass 5 minutes after leaving the house I knew it wasn't going to be a wasted trip as a fireball of about magnitude -6 tracked due westward beneath Castor and Pollux at around 5 degrees above the horizon and straight in front of me. It was the first of many.
I've just returned from a 3 hour observing session half an hour's drive outside Edinburgh. If you're reading this at about 03:00am GMT, then get outside, right now and even if you're suffering light pollution you'll get a good show.
The report posted here earlier from an American Observer regarding a high quantity of fireballs is not only spot on but the observed rate has increased. I counted approximately 270 meteors but given those streaking behind me and outwith the periphery of my visions I reckon it could well be as high as a rate of 120 meteors per hour or more as there seemed to be quite a few behind and above and behind me when I turned to gauge how many there were.
Of those I'd estimate about a quarter were magnitude -3 or brighter. Some were so bright that even if they were behind me they lit up the entire landscape in flash - like someone turning on the moon and suddenly turning it back off. Freaky is the only way to describe it. And its not just one at magnitude -10 or so, its a number of them.
The meteors are also leaving very long smoky trails (and clouds if the line of vision is foreshortened) one of which, from a particularly bright fireball (estimate -13 = Moon) persisted for almost 2 minutes leaving a bright white lit smoke patch briefly in the glare.
Early in the evening at 23.30 local time there were almost no fainter meteors visible and almost all those visible were magnitude 0 or brighter. The rate was healthy. The rate increased with the radiant's altitude until at 02.00 local time more fainter meteors became more apparent - no real surprise there.
I don't know if anyone else can confirm this but the meteors definitely appeared to me to be appearing in clumps, sometimes, but not typically, as many as 6 in the space of a minute or so and then only one or two or maybe nothing for the next 2-4 minutes. IMO it would be a worthwhile statistical exercise for anyone so inclined to see if there is any correlation (should anyone have the patience to log the times so accurately) or whether its wishful thinking and trying to see a pattern in the chaos that doesn't exist (like cloud lore).
We may be 18 hours short of the predicted max at around 19.00 UT here in the UK but this display has been more than worth the long wait.
I have just finished an observation session from nearby Winchester in the UK from 01:00 to 03:00 UT 17th November..
I have observed upwards of 70 or so meteors in this period. They appeared to come in groups - 3 or 4 over as many seconds on occassion then a period of inactivity. Magnitudes varied - some in the 1 to 2 mag range, but most negative including the most brilliant I've ever seen at 1:52 UT - blue white, mag -8/9 (I was never very good at estimating these...) travelling over 120 degrees of sky. After about 90 degrees it brightened enormously (briefly) and then faded over the remaining 30 degrees of its track leaving behind an almost emerald green trail that persisted for well over a minute for about 30 degrees of its track, up to the point where it suddenly brightened. It may have been my imagination but I almost thought I heard something at the instant of brightening (wishful thinking?). I've had to pack the session in now because it's getting damn cold and the sky is getting very hazy. I'm not too sure what the weather is going to be like tomorrow night but it should be worthwhile if the gods play ball.
The Leonids are putting on a superb show as I type this while warming up between meteor spotting sessions. Conditions are good, with no cloud and an approx mag 4.8 limiting magnitude on the southern edge of Edinburgh.
Nov 16 23:50 - Nov 17 00:40 UTC: (With the radiant very low) 29 Leonids, 1 N Taurid, 1 sporadic Nov 17 01:10 - 01:57 UTC 50 Leonids, 1 N Taurid
The vast majority of the Leonids are of negative magnitude and leave trains which persist for 1-3 seconds. I have classed 14 as mag -5 or brighter, though they are hard to estimate when they are so bright. The brightest has been about mag -10 and left a train which lasted for four minutes as upper atmospheric winds distorted it into a V-shape. The brighter ones appear distinctly orange, which is a surprise.
-- Alan Pickup | COSPAR 2707: 55d53m48.7s N 3d11m51.2s W 156m asl Edinburgh | Home: email@example.com +44 (0)131 477 9144 Scotland | SatEvo page: http://www.wingar.demon.co.uk/satevo/
Ton Schoenmaker, PA0EFA
Meester Homanstraat 8
Recent background information:
THE LEONID SAMPLE RETURN MISSION -- NASA scientists hope to capture a Leonid meteoroid and return it intact to Earth using a collector carried aloft by a helium-filled weather balloon.
NASA SPACECRAFT TAKE COVER FROM THE LEONIDS -- but the Hubble Space Telescope won't stop observing. Includes the basics of meteoroid impact hazards and how to track your favorite satellite during the storm.
Links to live webcasts, prospects and general background information (1998)