14 - Trapped: the Leonid Filament

Summary

At the start of the Leonid season in November, 1994 the weather had worsened moving into late fall and, because of a full Moon that year, the interest in the shower was low. A full Moon would wipe out the faint annual Leonids (ZHR ∼13/h), but perhaps not an outburst of bright meteors like that of 1961. An observing campaign was organized in the San Francisco Bay Area with the help of local amateur astronomers led by Mike Koop of the SJAA and Mike Wilson of NASA Ames. In 1961, rates peaked in the night prior to the nodal passage and, expecting the same, all of us went out in the night of November 16/17, 1994. Unfortunately, it rained water instead of meteors that night.

There were no volunteers for another campaign the next night. Work beckoned and it was deep in the night when I returned home around 12:30 UT. Before entering my apartment, I noticed the sky was clear. Still blinded by the car lights of opposing traffic, I quickly adapted to night vision by staring at my feet and blinking my eyes repeatedly while standing in the dark. I glanced up at the light polluted sky. Above my head was the constellation Lion in a clearing between trees. Well, there was one nice bright Leonid and not far from the radiant either! There was another one! I rushed inside to get my lawn chair, observing forms, and gnomonic star charts, and by 12:34 UT I was back out observing (Fig. 14.1).

From the start, I noticed many bright Leonids, falling left and right to the horizon at a rate I would have expected only for a good return of the August Perseids. One bright Leonid crashed in the zenith with a flare in the middle. Twilight set in at 14:00 UT. I phoned my friends in the Netherlands and then drove back to NASA/Ames to warn others by electronic mail.