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(meteorobs) shower predictions



Hi!

I thought I'd give my opinion too. Predictions such as the last one with
2000 HD74 should not be passed to the general public, but I think it
might be good to warn the most active observers about it. The
possibility of a meteor shower from an asteroid such as 2000 HD74 is
obviously very small, so there is a very small possibilty of the general
public missing something. I think that the risk of missing something
significant is low or almost nonexistent compared to the risk of the
entire thing being overblown - like the last November's LINEARIDS. I'm
not saying there were no Linearids, but obviously most observers were
biased as they were seeing Linearids several days around the predicted
peak and none during the peak (if I recall right...). No offense to
anyone...

When someone finds out that there is a new cometary or asteroid orbit
crossing Earth's, it should be assessed of how likely it is it will
produce meteors. Near Earth asteroids such as 2000 HD74 have a very low
probability of producing a shower, a potential shower should be looked
for AFTER it's possible peak. Warning the observers prior to it would
introduce bias into their observations. With new periodic comets, such
as G1 LINEAR and Tilbrook I think it's ok to notice the observers about
possible activity, as the probability of a shower from such a body is
greater. I don't know about meteors from Tilbrook, but it would be
really easy to miss one or two meteors coming from UMa (where exactly?
UMa is a pretty big thing!) with 80+ Geminids per hour and 20 or more
sporadics per hour. They would have had to produce at least 5 meteors
per hour to get my attention during all the excitement with the
Geminids! And G1 LINEAR - we might see a shower from this source...
...or not, as with meteors from Hartley 2...
...but as far as possible meteors from periodic comets are concerned, in
my opinion, at least the experienced observers should be noticed.

With long period comets, the probability of a new meteor shower is
obviously low as last year's Linearids hawe shown. But then again, Eta
Lyrids prove otherwise...  I'm not quite sure about what to do with
these showers. I fear that next year people will all be seeing 5 to 6
Eta Lyrids per hour...

Observing very minor showers is quite a tricky thing, and most of the
predicted showers would fit into this class. I do quite a lot of
observing and several times three or four meteors have formed radiant or
a meteor would hit a predicted radiant, but I don't get excited about
this. If my next observation shows increased probability of the
existence of a radiant I will privately contact an experienced observer
who was out at the time. And to Mike Linnolt - I would not go as far as
to call a single meteor a definite member of a possible shower, such as
the Linearids. I'd rather call it 'possible' and if two or three more
surfaced among my plots, then I'd think they are pretty definite. It was
like this with my Eta Lyrids - observed on May 6/7 (with no knowledge
about the shower's existence!) and saw 3 meteors from the radiant in 3
hours, 2 were immediately excluded due to wrong speed and the third one,
well, I still call it 'a probable Eta Lyrid'. What I'd like to point out
is one should be very careful when making shower associations. With
sporadic rates 10 to 20 per hour and a minor shower ZHR of 1 or 2, it's
really tricky to call ANY meteor a definite member. But I really have a
feeling I'm going to be flamed for this one...

To conclude, warnings should be issued only for possible showers from
periodic comets, and only from those that we come fairly close to their
orbits, as I think the probability of a real shower is the greatest.
With other sources we should go meteors first - parent body later. We've
had predictions of possible radiants several times in the past year or
two, but the new showers that have surfaced (XBO and the unpredicted JBO
outburst) totally unpredicted. On the other hand, I think John put it
very well - forewarned is forearmed!

Well, this is my opinion on the entire matter, but in any case I'm
passing my last final exam today, and from tomorrow it's observing
meteors for the next 4 months! I should get a life... :)

Clear skies!

Jure A.

P.S. - to Mike Linnolt: I did not want to be offensive in any way and it
is great to have active observers like you, but this Linearid thing
really bugs me...

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