HD TV observation of the strong activity of the Giacobinid meteor shower in 1998

Prominent activity of the 1998 Giacobinid meteor shower was observed from 1 1h UT through 15h UT on October 8 in Japan. We carried out a high-sensitivi ty HD-TV observation of this activity at the Dodaira station, and detected 341 Giacobinid meteors, along with 127 sporadic meteors. The peak activity was around 13h05m UT with an peak influx rate of meteoroids of 1.6 x 10(-5) km(-2) s(-1) (magnitude less than or equal to +7). The peak corresponded t o solar longitude 195.071 degrees (equinox J2000.0), which is different fro m the expected maximum of the Giacobinids at the solar longitude 195.4 degr ees (equinox J2000.0). The duration of the peak activity is shorter than th at of the previous outburst in 1985. The apparent brightness ratio of the f aint meteors during our observation is about 2.1, which is a rather small v alue compared to previous displays.