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(meteorobs) Bradfields
Steve Quirk and I operated our video cameras last night and recorded no
"Bradfields" (meteors from C/1976 D1) from 10 UT to 19 UT. The video rate
during this period must have been less than 5% of the sporadic rate for
mag 2 or brighter meteors and less than 1% for mag 5 and brighter meteors.
This is no surprise as being outwith the predicted time of encounter.
Due to the possibility of fireballs (Using Kozai's theory, Syuichi Nakano
(private communication) estimated an ejection speed of 2.0 m/s, real
fireball ejection velocities, and a 2003 Mar 01.914 TT encounter) my
partner Tanya and I watched the twilight to daylight sky from 19:30 UT
till 23:00 UT but saw no meteors. Venus was quite easy to see, so in the
darker part of the sky we watched, the limiting mag would have been about
-2 to -3 with fireballs of mag -5 presumably easy to see.
These predictions (Lyytinen & Jenniskens and Nakano) used the nominal
comet orbit with a 1058 AD previous perihelion. I'm not sure what effect
the orbital period uncertainty in the comet (+/- 50 years) would have on
the predictions. It would presumably have quite an influence on the
observed rates, but may have little influence on the encounter geometry.
Cheers, Rob
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