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(meteorobs) IMO Shower Circ. Draconids 1998
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I M O S h o w e r C i r c u l a r
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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 informa-
tion 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):
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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):
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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):
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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):
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Period(UT) ZHR +- [1/sqrt(n)]
1336-1421 562 53
Report by Milos Simek (Czech Republic, radar):
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1330 maximum of 400 events per hour at unfavourable
radiant geometry
Report by Bev Ewen-Smith (Portugal, radio):
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-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):
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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):
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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