(meteorobs) RE: HALWA May 13-14 2007

meteors at eclipse.net meteors at eclipse.net
Tue May 15 12:56:51 EDT 2007


Well, I'm not sure if I'm dedicated or just stupid :)
Still, there is something satisfying about knowing that at that moment I
was probably the only person in the world watching for meteors. And I was
really rewarded with the two Sporadics at the end.

This issue also came up with the recent Lyrids post peak.
In Europe, from 00 UT to 0255 there were 14, decreasing to 3 observers
that reported data via the IMO online form. The last signed off in morning
twilight at 0256 UT.
Then there was the Atlantic gap. For some reason we have no observers
along the Mid-Atlantic ridge. :)
Here on the other side, there were at most 2 observers at a time who
either reported via the IMO omline form, or posted here on meteorobs,
whose data I know will get to the IMO VMDB. Richard started ar 0404 under
poopy skies, and signed off about the time I logged on. Pierre started
after my high rates were over. Wes started just as I was ending. So for
much of the night, one of us was observing alone.

And sadly during the hour when I had my highest rate (ZHR 31 +/-9), while
admittedly statistically weak, I was the only person watching those
unexpectedly high rates. In fact during that entire night (more correctly
morning) there were only 4 observers in North AMerica. Myself, Richard
Kramer in MA, Pierre Martin near Ottawa, and Wes Stone in the great
Pacific noerthwest. That's it. The southwest was clouded out. Pierre
started after my highest rates were over. SO here I am with this unique
data set of observations, but since I was the only one...what does it
mean?

As to the polygon star count method of measuring LM, I believe (though
could be wrong) that it originated early in the IMO days. I like it
because, if implemented properly, it provides a sample over the entire
field of view, not just a specific star in one location.
I try to measure one area near the zenith, one near my field of view, and
at least a third to give a representative estimate for my whole field of
view. That's especially important here, where a good night is +5.7 or
+5.8.
Unless Lew is here, man are his eyes better than mine (reflected both in
LM estimates and meteor counts)

I'm sure Rainer and Malcolm can comment in more detail regarding that LM
estimation methodology.

Wayne



> You're an animal, Wayne! I admire your patience. If I don't see anything
> in a half-hour, I'm gone. I have to see SOMETHING or I just can't keep
> watching the skies.
> By the way, there's been the on-going discussion about the origin of the
> ZHR; what about the origin of the limiting magnitude method of counting
> stars in particular areas of the sky? There was no such method (that I'm
> aware of) used back in the early 1970s even though there were ZHRs being
> reported. We now use limiting magnitudes as a regular part of ZHR
> determination, so ZHR determination must have been an evolving process.
>



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