Draconids 1998: results

Visual and Radio observations by DMS, NMS and IMO


red_dot1. DMS preparations
red_dot2. DMS visual observations
red_dot3. More DMS visual results
red_dot4. Meteor Scatter Peter Bus
red_dot5. Meteor Scatter Ton Schoenmaker
red_dot6. Meteor Scatter Wim Zanstra
red_dot7. NMS: Preliminary results!!
red_dot8. NMS: Outburst of Giacobinids!
red_dot9. IMO Shower Circular
red_dot10. Recent IAUCs
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    2

I 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    2

From 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 +- 2

This 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    108

A 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.

Draconids 1998

Figure 2.

Draconids 1998

Figure 3.

Draconids 1998

Figure 4.

Draconids 1998




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/hour

Observations 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:


Draconids 1998

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).


Draconids 1998

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


Draconids 1998

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.


Draconids 1998

Figure 2: Sporadic background (spor) estimated from measurements in preceding years (vorm) and recent samples (hoogte).


Draconids 1998

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.


Draconids 1998

Figure 4: Reflectiontime (rt, in sec) per hour, also computed per 30 minute intervals and corrected for itself and breaks.


Draconids 1998

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, Florida

Operations 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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