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(meteorobs) FWD: revised data 1996
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Hello everybody,
Recently, I have taken a new look at our 1996 Leonid data from the
'narrow peak' period. I recalculated rates from our data with more up to
date values for perception etc. This puts Koen and my observations more
on line (my Cp has changed to 1.4: I calculated with 1.2 in my initial
WGN report).
The difference is not big. Rates come out slightly lower when pouled.
Still compatible with a B~30 peak with ZHR ~90-100 on a background ZHR of
~50, combined resulting in peak ZHR ~140-150.
That is still higher than in the last ILW bulletin (#10, see last WGN issue)
, and that difference is too large to be solely due to a different choice
of some parameters (actually, only gamma and the inclusion of perception
correction is different in our analysis) Reasons could include:
1. our rates are slightly too high, because some of us might have a
slightly better perception for faint meteors than average.
2. The ILW rates are to low because of: larger intervals, use of sliding
mean, but most notably, I suspect it includes observers who did not pay
full attention to the faint meteors, lowering their ZHR. This could
explain the scatter that is noted in the ILW analysis. Note that in the
ILW bulletin this effect is remarked upon (the missing of faint meteors)
in the context of the r-values determined.
I suggest both explanations might be at play. Given the uncertainties in
both analysis, I think it is best to conclude that the 1996 narrow peak
maximum ZHR was somewhere between 100 and 150.
-Marco Langbroek
Dutch Meteor Society
Revised rates. Data before 3:40: M. de Lignie and J. Nijland. After 3:30:
M. Langbroek and K. Miskotte. See also reprot in WGN December 1996.
LEONIDS 16/17 NOV 1996
UT ZHR +/-
3:08 57 10
3:37 62 13
3:55 76 15
4:10 83 12
4:29 87 12
4:49 143 17
- clouds-
5:47 73 18
Note: r=2.5 was taken, but since Lm was ~ +6.5, this has little to no
influence on the rates calculated.