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(meteorobs) meteor prediction debate

Hi Folks

I just want to throw some comments/observations in to the debate which are
actually more akin to questions than
suggestions/orders/recommendations/whatevers.

i) _IF_ P/2000 G1 LINEAR chucks out the odd meteor starting March 2003
[late March at last sums], would folk notice an evening radiant near mu
Leporis that was low to the Northern Hemisphere sky's south horizon and
would be set by midnight, if they hadn't been forewarned?

ii) eta Lyrids: they've been around a while it seems. The Japanese appear
to have noticed them first from general observation work.  The Dutch
Delphinus team have been monitoring them for some years. Very recently a
lot more people have seen them because of postings here, ie because they
have become aware of them.  Including some experienced observers who hadn't
come across them before.  However,  most people would be concentrating on
getting up early to look at eta Aquariids this time of year, not nipping
out to their observing site just after tea/dinner.

iii) Northern Piscids: a much understudied shower.  Is this because
everybody is busy staring in a direction more suited to noting Giacobinids,
a more or less contemporaneous shower? If a radiant isn't given, shouldn't
at least a general compass direction be given, and suggestion as to whether
evening or morning is best?  After all, just before sunrise is the best
time for meteors according to all the books/guides etc, biasing people
towards midnight or later.

iv) Weak streams are very difficult at best. If only plotted, fully
reported, data, and further the "two path lengths rule", are considered in
any *scientific* assessment, as opposed to personal assessment, can bias
still get through such safeguards?  In that way people could be happy
enough in their own mind as to whether a meteor was a sporadic or a
LINEARid, even if scientifically it only got chalked up as a sporadic.
Weight of numbers would also be applicable here: if only one plotted meteor
was known for any putative shower, it'd still be taken as a coincidental
sporadic by most.

v) Weak streams are very difficult, with very low rates.  Wouldn't
observers need as good a set of info as possible in order to be able to
detect meteors from said? Maximum dates are approximate, & observers should
be observing either side of this, when possible, anyway, just in case.

vi)  It is actually getting a bit too easy for anyone to predict a shower:
that's why I qualified my 2000 HD74 statements! There are no suitable
guidelines for assessment of what is good or bad: after all, the
professionals have only just tied down the behaviour of the relatively well
known Leonids! _I_ should have checked the meteor databases for any similar
candidate orbits, but did not [hiss, boo, I'd probably cry, if at had been
somebody else]!

vii) Ecliptic &/or short period objects can nearly always be suspected of
producing meteors, but don't deign to do so: 15P/Finlay & Lexell's Comet
come to mind re oft predicted yet never confirmed.  However, if the object
is long period & inclined somewhat, is it any less likely to be a 'false
alarm'?  [I've seen some few meteor orbits for January meteors with
'Hale-Bopp' written next to them as a suggested parent, what do most folk
think of that?].

viii) Possibly the most important question is "What false alarm to real
event ratio are observers willing to put up with?"

Finally, obviously any and all predictions should carry as much assessment
as possible re likelihood.  After all, every now & again the journos might
pick something up, & they rarely get the hard astro facts right!

v.important debate from Lew Gramer here, mostly 'cos the folk who mess
about with data aren't always the same as those that do the observing [I'm
a meteor "watcher", not a meteor "observer"].

Finally, I've just Drummond D' criterioned 2000 HD74's elements agin the
photo and radio databases, and there's not a statistical sausage come out
of it!  Not one meteor orbit passed, so the likelihood of meteors from this
object is even nearer zilch, if not less.  I should have done this in the
first place, but it should very much be noted that the meteor orbit
databases are very gappy, and at some times concentrated on the major
showers.  In a couple of years the results from the AMOR all year radar
stuff should be available, once Dr [Prof?] Baggaley's students have
finished their doctorates etc.  No solace to us Northerners, however.

Sorry for the false alarm, thoroughly glad of the ensuing debate.

Cheers

John

John Greaves
UK

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