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(meteorobs) More of Lew's "Trying Meteor Questions"
Well, I FINALLY got out for another short observing session again last night.
(My little IMO report to follow.) What a *pleasure* to sit out in the backyard
in shorts, and not have to think about frozen tape recorders, brass monkeys, or
anything else EXCEPT that lovely clear sky overhead... <sigh>
Not to think of anything, that is, EXCEPT the picayune DETAILS of scientific
meteor observing! ;> Questions that came up for me during the quiet times last
night (and with LM=5.5 skies in mid-July there were MANY quiet times), were:
o Quite often during my sessions, a meteor will be observed from 10, 20, 30, or
even 40 degrees outside the center of my vision. This causes no problems to my
data collection, even while plotting meteors, as I can generally get a fairly
good fix on meteor start and end points relative to the stars even at 40o out.
BUT, I couldn't help wondering last night if those "start points" I was
recording really made any sense! After all, whenever I see a meteor from a
distance of 10 degrees or more from my center of field, I'm really not catching
the start of it! This affects not only plotting accuracy, but might also affect
shower assignment during counting observations... After all, shower association
depends not just on path and speed, but also on the observed LENGTH of the
meteor's path - which we may not be seeing all of! Any thoughts on this?
o A similar thought occured to me regarding meteor magnitudes. Quite often with
fireballs, people will readily notice that the fireball begins at one magnitude
(say -1) and then increases in brightness (quickly or slowly). What exactly is
our reason for thinking that this doesn't also happen regularly with fainter
meteors?? For instance last night, I noted a meteor of mag 4 which was quite
short, but for which I caught a glimpse of a fainter end-trail (probably mag 5).
This made me wonder about the meaningfulness of magnitude distributions from
visual data: for we assume that there's a direct mapping (on average at least)
between meteor magnitudes and meteoroid masses in a stream. But is the theory
really that all meteors of a similar mass & velocity will share the same
MAXIMUM magnitude during their burnup, as opposed to the same constant mag?
This seemed like a thorny question to me, in the dark at 2 in the morning. :)
Anyway, any thoughts on these obscure questions from the Experts of Meteorobs
would be welcome. Clear skies for the weekend, and many meteors y'all!
Lew