Draconids 1998: results
Visual and Radio observations by DMS, NMS and IMO
1. DMS preparations
Abstract
Casper ter Kuile
This page presents an overview on the
1998 October Draconid / Giacobinid
Obervational results of the
Dutch Meteor Society
Updated: October 11, 1999
Draconids 1998: Preparations Weather prospects for western Europe are extremely bad for observing the Draconids (Giacobinids).
Bus observers of the Dutch Meteor Society still try to catch a hole in the thick cloud cover which obscure the sky over almost all of western Europe from Moscow to London and from Madrid to Oslo.
Observers are: Robert Haas, Marco Langbroek, Marc de Lignie, Jos Nijland, Carl Johannink, Arnold Tukkers, Olga van Mill, Casper ter Kuile
They first gather at 12 h at Casper's home at De Bilt and then decide there to move father east to Germany. At Casper's home we have full internet connections available and we also have neighbour Jacob Kuiper who will supply detailed information on the weather situation.
A second stop at about 14 h will be at the home of Carl Johannink at Gronau which is just east of the German/Dutch border.
At Carl's home we have again the possibility to view the latest update of Meteosat satellite pictures from the internet (Dundee/Nottingham). Together with detailed information of Jacob Kuiper from the Dutch National Weather Service we will decide to move north (Hamburg), east (Hannover) of south (Bonn).
If all goes according to plan we have to arrive at about 19 h at our observing site somewhere in Germany. We then set up our equipment and try to observe the Draconid / Giacobinid meteorshower (storm???) if it will be visible at all.
Please stay tuned and visit this page frequently as our first results will be published at this site!
First observational results by DMS-teams [Message from Marco Langbroek]
Hello Peter, Rainer and others,
We have been lucky to some extend! We did experience a clearing right at the start of the night (late twilight). We were clouded out (and fogged out) within an hour after the start of our observations, but our first 40 minutes were very clear (Lm +6.3-+6.4). A clear albeit modest Draconid activity was apparent, so the shower indeed did re-appear after years of non- or almost non-activity, that is clear. My data suggest ZHR in the order of 9 +- 4 for a 0.75 hr interval centered around 18:45 UT. Early Radio MS data by Peter Bus suggest that a significant peak occured above Asia, in daylight for Europe. We perhaps catched a glimpse of the tail of an extended background activity. Note that we were clouded out already around nodal passage. Most Draconids seen by us were very faint, my brightest was a +2 through Aquila. Below my data, obtained from Lattrop Public Observatory in the East of the Netherlands.
Observer : Marco Langbroek LANMA Date : October 8/9, 1998 Location : Lattrop Public Observatory, the Netherlands, 52d 24' 57" N, 6d 57' 58" E UT Teff Lm Dra Spo 18:17-19:13 0.75 6.3 7 11 +2 +3 +4 +5 Dra 1 1 3 2 Spo 0 4 5 2I am very curious to know what observers in Asia perhaps have seen.
Cheers!
-Marco Langbroek
Dutch Meteor Society, the Netherlands
Draconid data MISKO & NIJJO / more ZHR results [Message from Marco Langbroek]
Hello,
Below the Draconid data from Koen Miskotte (MISKO) who observed from his home in Ermelo, the Netherlands and Jos Nijland (NIJJO) who observed from the Public Observatory at Lattrop:
obs.: Koen Miskotte MISKO loc.: Ermelo, the Netherlands, 52d 18'N, 5d 37'E date: October 8, 1998 UT Teff Lm Dra Spo 18:06-18:26 0.33 5.5 2 2 50% cloud cover 18:46-19:16 0.50 6.1 2 4 no clouds +2 +3 +4 +5 Draconids 1 0 2 1 Sporadics 0 4 2 0 obs.: Jos Nijland NIJJO loc.: Lattrop Public Obs., the Netherlands, 52d 24' 57" N, 6d 57' 58" E date: October 8, 1998 UT Teff Lm Dra Spo 18:21-18:55 0.57 6.2 3 10 +1 +2 +3 +4 +5 Draconids - 1 - 1 1 Sporadics 1 - 4 3 2From data gathered by Marc de Lignie and me (Lattrop), Jaap van 't Leven (Bosschenhoofd) and Koen's data above (excluding the period with partial cloud cover) and using an assumed r-value of 3.5 because of the weak meteor magnitudes, I get a preliminary ZHR of 8 +- 2 for the period 18-20h UT. For each observer individual ZHR-values are:
Koen: 6 +- 5 Jaap: 9 +- 4 Marc: 6 +- 3 Marco: 10 +- 4 Average: 8 +- 2This corresponds very well to the data reported by Arlt c.s. (Berlin, Germany) and Stomeo (Italy).
Presumably, this activity represents part of a low level background structure behind the main peak observed from Asia. Such a background was also present in 1985 (see P. Jenniskens, Astron. Astroph. 295 (1995), 206-235).
Even though we missed the spectacular display seen by our Asian collegues, we still feel very satisfied to have seen the Draconid stream displaying unequivocal activity, which is after all a very rare occasion! Also, only half a day earlier weather prospects looked very dim, so we are glad to have experienced a short period of clear sky (and Draconid activity!) at all. So we are really very happy at the moment!
Cheers!
-Marco Langbroek
Dutch Meteor Society, the Netherlands
Forward Scatter Meteor Observations of the Draconids/Giacobinids 1998 Observer : Eisse Pieter (Peter) Bus Location : Groningen, Netherlands (6 degrees 33' E, 53 degrees 13' N) Frequency : 72.11 MHz Transmitter Location : Wroclaw, Poland, 130 kW, Distance 740 km Antenna : Yagi, 3 elements, geographical azimuth 106 degrees (ESE), elevation 13 degrees. Receiver : Bearcat UBC 860 XLT Scanning radio, sensitivity 0.5 uV. Observation Method : Listening and counting in 5-minute intervals. Very Preliminary results All reflections Uncorrected Hour rates starting at UT: 7 8 9 10 11 12 13 14 17 18 19 20h -------------------------------------------------------------------- 112 92 120 101 193 200 183 96 56 67 85 108A half-wide maximum of the total Draconid activity is not calculated, because for this period the "sporadic" activity is yet unknown. However, the highest peak rates of about 1 meteor reflection per 12 second occurred between 13h05m and 13h20m UT. The mean "sporadic" activity for this period in the past is about >1 meteor per minute. Saturation of the signals occurred between 12h55m and 13h05mUT.
Long-lasting reflections (=visual brighter meteors)
The long-lasting reflections > 1 second shows a half-wide maximum around 12h45m UT. However, also the activity of the long-lasting reflections shows clearly the highest peak rates between 12h55m and 13h20m UT.
Figure 1.
On the x-axis: time in UT on Oct 8. On the y-axis: uncorrected counts per hour of all long-lasting reflections > 1 second, monitored on Oct 8, between 7h and 21h UT. The line represents the mean "sporadic" activity of long-lasting reflections. All observations are not corrected for dead-time, observability function after Hines and "sporadic" activity. Monitoring activity in the period around 7h UT and between 17h and 21h UT, if the Draconids were still active, it was below detection level. Note: between 15 and 17h UT there are no observations applied.
Figure 2.
Figure 3.
Figure 4.
Forward Scatter Meteor Observations of the Draconids/Giacobinids 1998 Observer: Ton Schoenmaker E-mail: schoenmaker@nfra.nl Location: Roden, Netherlands (06 26' E, 53 08' N) Frequency: 77.257 MHz Transmitter: Kielce, Poland; 100 kW, horizontal polarization Antenna: 4-element horizontal Yagi, geographical azimuth 105 degrees (ESE), elevation 15 degrees Receiver: home-made convertor followed by Barlow-Wadley XCR-30 Mark II; total sensitivity 0.3 uV for 20 dB S/N, bandwidth 4.5 kHz Observing: rectified signal from 455 kHz IF recorded with a Servogor stripchart recorder with a chart speed of 120 mm/hourObservations of the Draconids started at 12h19m UTC when the TV transmitter in Kielce was switched on. Immediately many reflections were recorded. At the 0.12 uV level, signals were nearly overlapping, signals of 0.3 uV or stronger could be separated most of the time. In contrast with the outbursts of Leonids 1997 and so-called new peak of the Perseids, not many long-lasting echoes were present. The longest reflections lasted about 1 minute. The recordings show that the peak of stronger signals preceded the peak of weaker signals by about 15 - 30 minutes.
The following table gives the uncorrected counts of signals stronger than 0.3 uV (column "A") and counts of signals stronger than least 0.12 uV (column "B"). Observations of 10 October are presumed to be sporadic meteors mainly.
Hourly rates for the indicated intervals:
| October 1998 | 8 10 UTC | A B A B ---------------+------------------------------- 12h19 - 12h30 | 131 272 15 62 12h30 - 12h45 | 132 332 15 62 12h45 - 13h00 | 84 348 15 62 13h00 - 13h15 | 92 360 * 12 71 13h15 - 13h30 | 48 332 12 71 13h30 - 13h45 | 48 276 12 71 13h45 - 14h00 | 72 280 12 71 14h00 - 14h30 | 30 164 15 77 14h30 - 15h00 | 30 118 15 77 15h00 - 16h00 | 35 122 8 64 16h00 - 17h00 | 21 88 18 59 17h00 - 18h00 | 25 107 11 58 18h00 - 19h00 | 28 89 16 67 19h00 - 20h00 | 19 84 14 67 20h00 - 21h00 | 23 71 21 66 * saturation level
Figure 1. Uncorrected hourly radio meteor rates of Draconids (red, filled squares and triangles) on 8 October 1998. For comparison the hourly rates of sporadics on 10 October 1998 (blue, open squares and triangles).
Figure 2. Stripchart recording of the Draconid outburst on 8 October 1998. At 12h19m UTC the TV transmitter in Kielce, Poland was switched on.
Forward Scatter Meteor Observations of the Draconids/Giacobinids 1998 (Wim Zanstra) On october 8 1998 a marked activity was observed of the Draconids (Giacobinids), caused by particles of comet 21P/Giacobini-Zinner. This weak comet crossed the earth orbit in the passed month.
The earth passed the decending node of the comet orbit on october 8 around 21 UT at minimal distance. Expectations of an outburst at this time did not materialize, alas for visual and photographic observers in our part of the world.
Other considerations with respect to meteoroid orbits led to the conclusion Draconid maximum should occur at 13:15 UT (Dr. E.A. Reznikov of South Ural University). This assumption proved to be true afterwards.
Meteor scatter observers (Ton Schoenmaker in Roden, Peter Bus in Groningen and Wim Zanstra) were observing continiously on october 8 and this resulted in observing the Draconidpeak between 13:00 and 13:20 UT. It is almost certain we are among the very few Dutch observers who actually observed the Draconid peak of 1998!
In dark area's in Asia and the America's many enjoyed the display. Maximum activity peaked at about 200 - 500 meteors per hour. But it is still to early for final results. The sudden activity in 1998 is striking because in years between comet passages almost no Draconids were observed.
On the website of the Dutch Meteor Society (http://home.planet.nl/~dmsweb/) a comprehensive overview is presented of worldwide observations.My observations are presented here. They are established under following conditions. Meteors are observed by detecting the reflection of radiowaves against the meteoroid path in the atmosphere.
Observer: Wim Zanstra E-mail: wimzanstra@freemail.nl Location: Appingedam Frequency: 72.11 MHz (FM-band) Transmitter: Wroclaw, Poland: distance 735 km Antenna: 5-element Yagi, UHF-antenna, optimal for wavelenght of 3 meters Receiver: Bearcat UBC 177 XLT; sensitivity 0.8 uV Observing: listening with an earphone
Figure 1: Hourly rates (nc) counted per 30 minute intervals, including sporadic background en corrected for reflectiontime and breaks. Maximum rate is 122 between 13:00 and 13:30 UT.
Figure 2: Sporadic background (spor) estimated from measurements in preceding years (vorm) and recent samples (hoogte).
Figure 3: Observabilityfunction of Hines (Fobs), which shows the chance a reflection may be received by a specific observer. Stronger reflections do not behave like Hines, so it is possible the actual peak is after the one according to these measurements.
Figure 4: Reflectiontime (rt, in sec) per hour, also computed per 30 minute intervals and corrected for itself and breaks.
Figuur 5: Reflections split into categories: weak reflections (red), medium strong reflections (blue), strong reflections (yellow) and reflections lasting longer than 5 seconds (lightblue). Obviously the medium strong reflections dominate during the maximum.
Draconids in Japan : Preliminary results ( 1998/10/11 ) Below is a much more detailed report from the Nippon Meteor Society on the October Draconid activity for October 8/9. This one includes the average numbers of shower meteors seen, in addition to the ZHR data.
The peak rate reported was an average of 55 GIA per hour, between 1300 and 1400 UTC, as averaged among their various observers active at that time. The breakdown into 10 minute periods shows the highest rate at about 16 meteors per ten minute bin, from 1300 to 1320 UTC. Note that the average number seen in the 10 minute bin is not reported directly, but has been multiplied by 6 to give an hourly rate of 96/94 for those time periods, which is then applied to the ZHR formulae.
Also note that the report lists the total number of "Perseid" meteors seen, which is probably a typo -- Giacobinid (October Draconid) is probably intended.
** begin forwarded message (from IMO-News) **
Date: Sun, 11 Oct 1998 19:31:00 +0900 Subject: Draconids in Japan : Preliminary results To: imo-news@imo.net, peter@max.arc.nasa.gov Visual results in Japan (The Nippon Meteor Society). ZHR has been computed with: - gamma = 1.0 (correction of Radiant elevation) - r = 2.6 (IMO Handbook for Visual Mereor Observers , Page 210) (1) Hourly Result - excluding:observations under unfavourable condition (T<30m, Lm<4.0, Cl>0.4, RP-h<10deg) UT JST N ave-HR(Dra) ZHR(Dra) SD Remarks Oct.8, 1998 09:00-10:00 8/9 18:30 4 7 41 21 10:00-11:00 8/9 19:30 7 7 35 19 11:00-12:00 8/9 20:30 14 13 105 45 12:00-13:00 8/9 21:30 18 24 304 133 13:00-14:00 8/9 22:30 25 55 585 319 14:00-15:00 8/9 23:30 20 14 230 135 15:00-16:00 8/9 00:30 8 3 156 123 16:00-17:00 8/9 01:30 1 2 140 Observers (38members) : T.Hashimoto, I.Hatsukade, D.Ito, K.Izumi, H.Izumimoto, Y.Kawai, S.Kaya, I.Kisanuki, W.Kobayashi, K.Kuragaki, K.Maeda, K.Mameta, T.Maruyama, K.Nakamura, Y.Nojima, K.Nozaki, H.Okayasu, K.Osada, M.Sakaguchi, M.Sato, T.Sato, M.Takanashi, A.Takeda, S.Takeda, K.Tanaka, Si.Tanaka, Sy.Tanaka, K.Terakubo, Y.Tonomura, T.Torigoe, S.Uchiyama, S.Uehara, Y.Yabu, M.Yamamoto, S.Yanagi, S.Yoshida, H.Yoshidome, S.Yoshino Total observations (Oct.8) ： 4,636minutes (="77.27h)" Total number of Perseid meteors (Oct.8) ： 1,862 (2) 10-Minutely Result (11:00-15:00 UT) excluding:observations under unfavourable condition (T<5m, Lm<4.0, Cl>0.4, RP-h<10deg) UT JST N ave-HR(Dra) ZHR(Dra) SD Remarks 11:00-11:10 8/9 20:05 3 2 13 23 11:10-11:20 8/9 20:15 4 2 12 23 11:20-11:30 8/9 20:25 5 17 147 34 11:30-11:40 8/9 20:35 5 13 126 143 11:40-11:50 8/9 20:45 5 18 165 86 11:50-12:00 8/9 20:55 5 17 211 120 12:00-12:10 8/9 21:05 8 18 218 97 12:10-12:20 8/9 21:15 8 20 248 111 12:20-12:30 8/9 21:25 8 21 265 166 12:30-12:40 8/9 21:35 8 31 412 201 12:40-12:50 8/9 21:45 12 61 530 304 12:50-13:00 8/9 21:55 14 64 614 280 13:00-13:10 8/9 22:05 13 96 943 595 13:10-13:20 8/9 22:15 15 94 904 565 13:20-13:30 8/9 22:25 15 64 616 437 13:30-13:40 8/9 22:35 16 42 483 223 13:40-13:50 8/9 22:45 15 26 307 197 13:50-14:00 8/9 22:55 13 30 371 227 14:00-14:10 8/9 23:05 10 25 325 145 14:10-14:20 8/9 23:15 11 14 196 143 14:20-14:30 8/9 23:25 9 16 230 188 14:30-14:40 8/9 23:35 4 8 90 110 14:40-14:50 8/9 23:45 2 9 224 110 14:50-15:00 8/9 23:55 2 9 239 114 Observers (23members) : T.Hashimoto, D.Ito, H.Izumimoto, Y.Kawai, W.Kobayashi, K.Kuragaki, K.Mameta, K.Nakamura, H.Okayasu, K.Osada, M.Sato, T.Sato, M.Takanashi, A.Takeda, S.Takeda, Si.Tanaka, Sy.Tanaka, K.Terakubo, S.Uchiyama, S.Uehara, Y.Yabu, S.Yanagi, S.Yoshino Total observations (Oct.8) ： 2,340minutes (="39.00h)" Total number of Perseid meteors (Oct.8) ： 1,402 See The Nippon Meteor Society Web Page. http://www2u.biglobe.ne.jp/~nms/index_e.html -------------------------------------------------------------------- Masaaki Takanashi (The Nippon Meteor Society / Gotemba city, JAPAN) E-Mail : QGA00120@nifty.ne.jp NMS-Web Page : http://www2u.biglobe.ne.jp/~nms/index_e.html -------------------------------------------------------------------- ** end of forwarded message **James Richardson
Tallahassee, FloridaOperations Manager / Radiometeor Project Coordinator
American Meteor Society (AMS)
http://www.serve.com/meteors/
IMO Shower Circular: Draconids 1998 Two orbital periods after the 1985 Draconid outburst, expectations were high for the night 1998 Oct 8-9. An outburst with activity of ZHR>500 occurred over Asian longitudes on 1998 October 8, 13h-14h UT. The information is based on visual reports as given by Koseki (Japan, 21 observers), a detailed report by Osada (Japan), reports from Xing Ming and Jin Zhu (China), a visual and video report by Jun-ichi Watanabe (Japan), radar observations by Simek (Czech Republic), radio observations by Ewen-Smith (Portugal) and Bus (the Netherlands).
Details of the reports are as follows; all UT times refer to 1998 October 8, save for the last period:
Report by Masahiro Koseki (Japan, visual): ------------------------------------------ Period(UT) ZHR +- [standard deviation] 0900-1000 14 6 (ZHRs were reported 1000-1100 23 11 by Koseki) 1100-1200 61 43 1200-1300 147 55 1300-1400 371 243 1400-1500 174 123 1500-1600 121 72 Detailed report by Kazuhiro Osada (Japan, visual): -------------------------------------------------- Period(UT) ZHR +- [1/sqrt(n)] 1050-1130 154 33 1240-1250 901 144 1250-1300 867 144 1300-1310 1082 165 1310-1320 1265 183 1320-1330 968 164 1330-1340 640 136 1340-1350 442 123 1350-1400 575 144 1400-1410 457 132 1410-1420 323 114 radiant below 20deg henceforth 1420-1430 302 114 1430-1440 193 136 Report by Jin Zhu (China, visual): ---------------------------------- Period(UT) ZHR +- [1/sqrt(n)] 1143-1227 230 45 Report by Jun-ichi Watanabe (Japa, visual-video): ------------------------------------------------- 1200-1330 ZHR>200 1300-1330 28 GIA on TV monitor with lm~6.0 and a field of view of 40deg x 20deg Report by Zhou Xing Ming (China, visual): ----------------------------------------- Period(UT) ZHR +- [1/sqrt(n)] 1336-1421 562 53 Report by Milos Simek (Czech Republic, radar): ---------------------------------------------- 1330 maximum of 400 events per hour at unfavourable radiant geometry Report by Bev Ewen-Smith (Portugal, radio): ------------------------------------------- -1000 no enhancement 1000-1200 increase of short events (<10sec) 1200-1400 4 events (10-20sec) per minute 1400-1415 decrease of short events, a few very large events (1min) Report by Eisse Peter Bus (the Netherlands, radio): 0700-0800 9 events>1sec 0800-0900 14 0900-1000 28 1000-1100 33 1100-1200 64 1200-1300 97 maximum suggested at 1245 UT 1300-1400 90 1400-1500 31 Report by Ilan Manulis (Israel, visual): ---------------------------------------- 1541-1741 5-7 per hour, group observation 1741-1836 1-2 per hour, lm=5.5-6.0 European results (visual): -------------------------- Period(UT) nGIA ZHR 1715-1815 7 24 Helle Jaaniste (JAAHE), Estonia 1745-1818 2 6 Jurgen Rendtel (RENJU), Germany 1750-1821 4 15 Rainer Arlt (ARLRA), Germany 1818-1855 3 8 Jurgen Rendtel (RENJU) 1821-1853 2 7 Rainer Arlt (ARLRA) 1817-1913 7 12 Marco Langbroek (LANMA), the Netherlands 1833-1903 4 21 Ike Lysell (LYSAK), Sweden 1837-1926 4 10 Enrico Stomeo (STOEN), Italy 1855-1930 0 - Jurgen Rendtel (RENJU) 1853-1931 0 - Rainer Arlt (ARLRA) 1845-1945 7 40 Jaak Jaaniste (JAAJA), Estonia 1912-1926 0 - Stephen McCann, UK 2010-2045 2 13 Erico Stomeo (STOEN) 2242-2247 0 - Jurgen Rendtel (RENJU) 0250-0330 0 - M. Linnolt, California, USA [1998 Oct 9]If not explicitely mentioned otherwise, ZHRs were calculated by myself with r=2.0, alpha=262, delta=+54. A high proportion of faint meteors were reported during the peak; the ZHRs may thus be underestimated. We can conclude that the Draconid maximum occurred at lambda_sol=195.078+-0.010 degress (eq. 2000.0).
----
Rainer Arlt, 1998 Oct 9
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