Outburst of Giacobinids in 1998.


Generally speaking of Japanese observation until this time, Giacobinids activity was almost limited at maximum day. But, Giacobinid shower activity had already started a few days before maximum day in this year. Some observers witnessed its meteors and detected its radiant points.


Giacobinids was outburst on October 8. According to the analysis of rate of 10 minutes interval, It seems that The peak of Giacobinids was around 13h10m(UT) and lambda = 195.075. The activity was about HR=50 (ZHR=400 by NMS).


Giacobinids activity finished on October 11.


Observers : 
  Hashimoto Takema  : HASTA
  Ito Osamu         : ITOOS
  Kondo Hideki      : KONHI
  Osada Kazuhiro    : OSAKA
  Maeda Koji        : MAEKO
  Numazawa Shigemi  : NUMSH
  Sakaguchi Mitsue  : SAKMI
  Sekiguchi Takashi : SEKTA
  Tonomura Yasuhiro : TONYA

Observation Period :
  October 2-8, 1998.

Observation site:
  HASTA : Mt.Momokura, Ohtsuki, Yamanashi, Japan    E:139.0 deg , N:35.6 deg
          Hachioji, Tokyo, Japan                    E:139.4 deg , N:35.6 deg
  KONHI : Narusawa, Yamanashi, Japan                E:138.8 deg , N:35.5 deg
  MAEKO : Kiyotake, Miyazaki, Miyazaki, Japan                   ,           
  NUMSH : Mt.Akagi, Gunma, Japan                    E:139.2 deg , N:36.4 deg
  OSAKA : Oyama, Shizuoka, Japan                    E:139.0 deg , N:35.3 deg
  SAKMI : Higashi-Hiroshima, Hiroshima, Japan       E:132.6 deg , N:34.5 deg
  SEKTA : Asahi, Kawagoe, Saitama, Japan                        ,           
  TONYA : Mekawa, Miyagi, Japan                                 ,           

Observation method:
  visual , plotting
           counting (only Maximum day)

Observational Data:
  DATE    UT         JST    TIME  aM Spo Gia  Lm CL Dir Obs.  Meth.
  ----------------------------------------------------------------------
  Oct/1998
  02 10:30-11:30 19:30-20:30 60    6   4   2  5.3 0 Dra HASTA V(P)
  02 11:30-12:30 20:30-21:30 60    4   4   0  5.1 0 Dra HASTA V(P)
  03 11:00-12:00 20:00-21:00 60    9   8   0  5.0 2  Z  OSAKA V(P)
  03 12:00-13:00 21:00-22:00 60   10  10   0  5.0 1  Z  OSAKA V(P)
  03 12:30-13:30 21:30-22:30 60    6   6   0  4.6 0 Cyg HASTA V(P)
  04 10:00-11:00 19:00-20:00 60    8   7   1  4.8 2  Z  OSAKA V(P)
  04 11:00-12:00 20:00-21:00 60    7   5   2  5.0 2  Z  OSAKA V(P)
  04 12:00-13:00 21:00-22:00 60    9   7   2  5.2 1  Z  OSAKA V(P)
  05 10:00-10:50 19:00-19:50 50   10   6   4  5.1 0 Dra SAKMI V(P)
  06 09:15-10:15 18:15-19:15 60    8   6   2  5.0 1  Z  OSAKA V(P)
  06 10:15-11:30 19:15-20:30 75   12   8   4  5.0 2  Z  OSAKA V(P)
  07 11:45-12:47 20:45-21:47 53    3   3   0  4.3 1 Cep MAEKO V(P)
  07 12:05-12-40 21:05-21:40 35   10   5   5  5.1 3 Dra SAKMI V(P)
  07 12:51-14:00 21:51-23:00 61    2   2   0  4.8 0 Cep MAEKO V(P)
  Maximum activity was reported as follows
  09 10:15-11:00 19:15-20:00 75    4   1   3 10.0 0 Dra TONYA T(P)
  09 10:30-11:30 19:30-20:30 60   17  15   2  5.2 2  Z  OSAKA V(P)
  09 11:00-12:00 20:00-21:00 60    3   0   3  9.0 0 Dra TONYA T(P)
  09 12:00-13:00 21:00-22:00 60   15   9   2  4.8 3 Dra SAKMI V(P)
  10 12:45-14:00 21:45-23:00 75   21  14   1  5.5 1  Z  OSAKA V(P)
  11 10:00-11:00 19:00-20:00 60    4   0   2  6.0 0 Peg TONYA V(P)
  11 11:00-12:00 20:30-21:00 60    5   1   1  6.0 0 Peg TONYA V(P)

  TIME    : Observed time interval
  Total   : Total number of meteors
  Spo     : Sporadic meteors
  Gia     : Giacobinids
  Lm      : Limiting magnitude of field stars
  CL      : Cloud cover
  Dir     : Observation direction(Z : Zenith)

Radiant point:
No.   Ls      YMD(UT)        CONST  R.A   DEC   N   d  Wt  Vel   Mag   HR  Obs.  Meth
------------------------------------------------------------------------------------
1. 191.066 1998/10/04.48 Gamma-Dra 262   +52    4   1.5 1  S-rS  2.8  1.3  OSAKA V(P)
2. 192.011 1998/10/05.44    Mu-Dra 257   +54    4   3   P  rS    2.5  4.8  SAKMI V(P)
3. 192.986 1998/10/06.43 Gamma-Dra 265   +55    5   3   1  S-rS  3.2  2.2  OSAKA V(P)
4. 194.051 1998/10/07.51  Beta-Dra 265   +52    5   3   P  S-rS  1.2  8.6  SAKMI V(P)
5. 194.998 1998/10/08.47 Gamma-Dra 265   +53   15   3   2  S-rS  1.2  6.4  SAKMI V(P)
6. 195.048 1998/10/08.52    Xi-Dra 270   +57   23   2   2  S     3.0 26.0  KONHI TV  21h05m-21h59m
7. 195.067 1998/10/08.54    Xi-Dra 271.0 +58.2 22   4   4  vS    3.0 11.0  NUMSH TV  24mmF1.4,50mmF1.2,85mmF1.2,21h00m-23h00m
8. 195.087 1998/10/08.58 Gamma-Dra 267.4 +57.1  5   3   5  S     1.4 36.0  SEKTA TV  20:00-23:00,28mm,F1.8,48deg

  N      : Number of meteors
  d      : Diameter of R.P.
  Wt     : Weight(P,1-5  P : poor)
  Mag    : Mean Magnitude
  Vel    : Velosity(vS S rS M rR R vR)
                   <-Slow      Rapid->
Method : V:Visual T:Telescopic, P:Plotting C:Counting

Fireball
  10/07  12h11m21s(UT)  Mag=-3  Vol=rS  298,+47 -> 310,+43

Other information as below.
SAKMI saw a Giacobinid meteor around 10h UT on Oct. 1 and Oct. 3.
SEKTA saw a Giacobinid meteor with 0 magunitude at 9h44m UT on Oct. 2.
ITOOS saw a Giacobinid meteor with 1 magunitude around 10h UT on Oct. 6.


Search for NMS radiant point database with following requirements.
  [requirements]1970-1998, 10/1-20, 247277, 3969, N4

  Ls      Date(UT)      R.P name  R.A Dec  N  d Wt Vel   Mag   HR Obs.              Method
  ----------------------------------------------------------------------------------------
  196.603 1931/10/09.92       -   265 +53  5  -  2 -      -    -  -                 V
  197.465 1953/10/10.438      -   265 +52  5  -  2 -      -    -  -                 V
  196.406 1969/10/09.46       -   265 +54  5  -  - -      -    -  -                 V
  195.932 1971/10/09.5  Gamma-Dra 263 +52  4  -  - -      -    -  Oikawa Kiyohiko   V
  195.454 1985/10/08.60 Gamma-Dra 264 +58  8  3  1 -      -   3.0 Ueda Keiko        V
  195.365 1985/10/08.51    Nu-Dra 266 +55  4  3  1 -      -    -  Fukuoka-Astron.G  V
  195.434 1985/10/08.58 Gamma-Dra 273 +53  7  -  - -      -    -  Kochi-Univ.G      V
  195.375 1985/10/08.52 Gamma-Dra 277 +55 13  5  1 -      -    -  Takanashi Masaaki V
  195.252 1997/10/08.47    Xi-Dra 271 +58  6  3  1 vS-S  2.7  2.0 Hashimoto Takema  V
  195.232 1997/10/08.45 Gamma-Dra 272 +54  6  8  1 vS-rS 3.3  2.0 Osada Kazuhiro    V

Maximum activity of Giacobinids (newsflash)
[Up date : October 10 at 16(UT). Written by Takanashi Masaaki and Transrated by Hashimoto Takema.]


Number of observers : 38
Total observation time : 4,636minutes
Number of Giacobinid meteors : 1,862

Hourly rate
-----------------------------------------------(NMS)---------(IMO)---
        UT             JST      N   ave-HR    ZHR   SD      ZHR   SD
                                            (r=1.6)       (r=2.6)
---------------------------------------------------------------------
Oct.8 09:00-10:00   8/9 18:30   4       7      19    6       41   21
      10:00-11:00   8/9 19:30   7       7      21   12       35   19
      11:00-12:00   8/9 20:30  14      13      56   30      105   45
      12:00-13:00   8/9 21:30  18      24     155   76      304  133
      13:00-14:00   8/9 22:30  25      55     393  244      585  319
      14:00-15:00   8/9 23:30  20      14     161  115      230  135
      15:00-16:00   8/9 00:30   8       3     107   74      156  123
      16:00-17:00   8/9 01:30   1       2      98    -      140    -
---------------------------------------------------------------------
Sellection condition as follows:
@|@Individual observation.
@|@Observation time is more than 30 minutes.
@|@Limiting magnitude is more than 4.0.
@|@Cloud cover is less than 4.
@|@R.P. altitude is more than 10 deg.

38 observers as follows:
  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


Number of observers : 23
Total observation time : 2,340 minutes
Number of Giacobinid meteors : 1,402

rate of 10 minutes interval
-----------------------------------------------(NMS)---------(IMO)---
        UT             JST      N   ave-HR    ZHR   SD      ZHR   SD
                                            (r=1.6)       (r=2.6)
---------------------------------------------------------------------
Oct.8 11:00-11:10   8/9 20:05   3       2       7   12       13   23
      11:10-11:20   8/9 20:15   4       2       6   12       12   23
      11:20-11:30   8/9 20:25   5      17      72   13      147   34
      11:30-11:40   8/9 20:35   5      13      62   69      126  143
      11:40-11:50   8/9 20:45   5      18      82   46      165   86
      11:50-12:00   8/9 20:55   5      17      88   34      211  120
      12:00-12:10   8/9 21:05   8      18     100   35      218   97
      12:10-12:20   8/9 21:15   8      20     114   45      248  111
      12:20-12:30   8/9 21:25   8      21     129   80      265  166
      12:30-12:40   8/9 21:35   8      31     203   96      412  201
      12:40-12:50   8/9 21:45  12      61     335  263      530  304
      12:50-13:00   8/9 21:55  14      64     385  226      614  280
      13:00-13:10   8/9 22:05  13      96     616  374      943  595
      13:10-13:20   8/9 22:15  15      94     627  386      904  565
      13:20-13:30   8/9 22:25  15      64     438  305      616  437
      13:30-13:40   8/9 22:35  16      42     327  169      483  223
      13:40-13:50   8/9 22:45  15      26     218  143      307  197
      13:50-14:00   8/9 22:55  13      30     267  173      371  227
      14:00-14:10   8/9 23:05  10      25     247  142      325  145
      14:10-14:20   8/9 23:15  11      14     155  129      196  143
      14:20-14:30   8/9 23:25   9      16     187  155      230  188
      14:30-14:40   8/9 23:35   4       8      87  117       90  110
      14:40-14:50   8/9 23:45   2       9     156   68      224  110
      14:50-15:00   8/9 23:55   2       9     171   74      239  114
---------------------------------------------------------------------
Sellection condition as follows:
@|@Individual observation.
@|@Observation time is more than 5 minutes.
@|@Limiting magnitude is more than 4.0.
@|@Cloud cover is less than 4.
@|@R.P. altitude is more than 10 deg.

23 observers as follows:
  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


Giacobinids are rich in faint meteors.  Sky conditions and perception
coefficient of observers affect heavily on ZHR estimates.  Bright Moon
hindered observations and SD are rather large.


According to the analysis of rate of 10 minutes interval, It seems that The peak of 
Giacobinids was around 13h10m(UT) on October 8 (lambda = 195.075).


There are detail data and information in the Nippon Meteor Society home page 

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