(meteorobs) Small scale structure in the JBO stream?? (was re: IMO METEOR SUMMARY REPORT: 23/24-Jun-2004...)

[Lewis J. Gramer]

FYI: I postal-mailed copies of my plots from this date to Bob
Lunsford in California, and Rainer Arlt in Germany today.

Pierre Martin writes:
> I just noticed that the IMO circular indicates the JBOs ZHR down
> to only one by the time you started your session on that night.
> This brings up maybe a possible explanation... Were you lucky
> enough to witness a highly localized small outburst of the JBOs???
>
> At least Bob Lunsford and Sirko Molau aleady reported seeing
> concentrations of activity on distinct periods.  Could it be
> that maybe the Pons-Winnecke June Bootids possess very small
> filaments that can produce such highly localized bursts of
> activity?


MICROFILAMENTS?!?

Pierre raises an interesting question - the very one that was
on my mind: Can activity from a very young stream really be so
fine-grained as to show different activity to different sites,
at the same time?? This same question has been discussed on our
list before - in regard to the Leonids, in particular:
  http://www.meteorobs.org/maillist/msg14026.html

The flying distance from Boston to Ottawa is shown as 433km, so
our two sites that night were probably separated by under 500km:
That's a VERY tiny sampling of the average meteoroid stream! And
of course, keep in mind that the activity I plotted was pretty
well distributed throughout my session (the times of individual
meteors given below), and the earth was whipping along at some
where near its average 108,000 km/hour throughout this period! :)

  UT    Definite/Possible?
  2:49  JBO?
  3:33  JBO
  3:34  JBO
  3:46  JBO
  3:54  JBO?
  4:07  JBO
  4:28  JBO?
  4:50  JBO
  4:55  JBO
  5:04  JBO
  5:15  JBO


STATISTICAL SIGNIFICANCE?

I guess the next step (from existing data), may be calculating
the likelihood that the activity I observed was just a "fluke":
basically, the question would come down to "How many standard
deviations above the mean was this reported activity of HR>=6,
for a shower whose ZHR - based on other observers' data at the
time - was 1 meteor or less?" IMO's processed data can probably
answer this question very easily - could anybody with that data
ready to hand, give me the mean and 1 SD for any reported JBO
activity during that period of 24 June 02h-06h UT?


OTHER OBSERVERS?

One thing that would certainly help unravel this for me - were
there any other observers plotting meteors, anywhere on Earth's
night side during those three hours Pierre and I were both out??
Some observers have reported in from that period - but I'm not
sure if they were plotting, and I think I recall that some of
these sessions had very marginal (high-correction) conditions?

If anyone else has reported in with plots for that night, don't
be shy about coming forward with the numbers you logged then!

(This really reinforces the fact that a single amateur, on his
or her lawnchair under a dark sky, really can make a difference!)


PLOTTING ERRORS?

Perhaps there were others out plotting that night! In addition,
it may be that once my own plots have been analyzed with more
expert eyes, some systematic error in my plotting technique
will become apparent, which can explain these meteors as being
misassociated with the JBO radiant. And BTW, if that IS true,
then it will be just as interesting (not to mention instructive)
to me, as finding out that the activity were apparently "real"!


Center of Field of View?

One brain twist that occurs to me in looking at my plots: I
was facing slightly closer to the potential radiant than Pierre
appears to have been. Could the shorter paths I was logging be
the cause of some misassociations? But the mere fact that I WAS
seeing short paths, close to the putative radiant, seems like
an indication that this activity WAS related to the stream...

Or a more interesting possibility: could the fact that I was
facing slightly closer to the radiant, have made any activity
more readily apparent to me - or more easily plotted? (I know
that Bob Lunsford often advocates looking much closer to the
radiant during an active shower, than many other observers do.)


VIDEO DATA?

Finally, one thing that this makes eminently clear to me: I have
a digital video camera now, and I have a (very cheap) GenII image
intensifier... Had I been operating this simple equipment along
with my plotting during this night's observing period, it would
probably be MUCH easier to substantiate (or invalidate) the JBO
activity that my plots seem to show for this night!

Do any others in the Northeastern US or Eastern Canada do video
meteors on a regular basis now? Would anyone else be interested
in teaming up with a fellow video neophyte - sharing ideas and
moral support, and maybe even trying multi-station observing, if
we happen to have observing sites close enough to one another?

If so, I would love to hear from you off-list.


Clear skies all!
Lew Gramer