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Re: (meteorobs) Persistent meteor trains

Larry wrote:

> I was having a seniors moment, of course it wasn't self luminous. Thanks
for the replies from Ed, Jure, and others.
> The self luminousity brings up an interesting question. Because the Moon
was almost full, could it have given some added brightness to some of the
longer lasting trails see during the 2001 Leonids??

    Uh, sorry Larry, that's two senior's moments. The Moon was full for the
2002 Leonids, and was not a factor at all in 2001. It's still a valid
question, though; would a full Moon highlight a fading train for a little
longer, or would the reduction in limiting magnitude be the greater factor?

> I was out at our dark site that night and a - 8 bolide that passed near
> Jupiter left a trail that I watched for about 10 minutes at 1x and for
over
> 20 minutes in my 80mm finder at 15x.

    I saw that one too, it came from the east and exploded as if it had hit
a wall directly between Castor and Pollux. The train at first took an
irregular shape before eventually taking an oval form, enwreathing Castor as
it expanded and faded like an extreme time-lapse exposure of the Ring
Nebula. Unforgettable. According to my tape recorded notes that train was
still faintly visible to averted vision a quarter of an hour later.

... and Ed wrote:

> >     What you saw from Edmonton were noctilucent clouds believed to have
been caused by the passage of the fireball.  These had drifted down from the
north and were visible later that evening.  I don't think that the actual
fireball was visible from Edmonton as it was heading in from the north
landing on Tagish Lake.  The train mentioned in your message is what is
called a "dust train".

    I also was fortunate enough to catch this dust train -- and thanks for
the correct terminology Ed -- some 8 hours after the Tagish Lake fireball.
An amazing sight. According to our alt-az calculations at the time, the
train had drifted down the Rockies to somewhere in the general vicinity of
Banff, AB, many hundreds of km from Tagish Lake and fortuitously aligned
with the setting sun from Edmonton's perspective. (Tagish Lake: 59º.7 N
134º.2 W; Banff: 51°.2 N., 115°.6 W; Edmonton 53°.6 N., 113°.4 W. At 17:40
MST the Sun's azimuth was 245°, 7 degrees below the horizon.)

    It was *not* a noctilucent cloud by the usual definition of that term,
we have observed those plenty here in Edmonton, and it was interesting to
compare the similarities and differences of structure and colour. I had not
heard of the fireball/meteorite at that point, and was at a loss to explain
how "sort of" NLCs could appear in the south in the winter. We were later
informed by some expert or other that the correct term for the formation we
saw was a "nacreous cloud" (root word: nacre, mother of pearl).

    Photos of that dust train can be seen at this site:
http://phobos.astro.uwodot ca/~pbrown/tagish/dustcloud.html

    Two taken by fellow Edmontonian Mark Zalcik show the sunset glow to the
SW, while the one taken by Larry Wood (who wrote the initial message above)
was taken a few minutes earlier. While I'm not sure one can satisfy the
purists that this fits the definition of a persistent meteor train, it was
without doubt an observation as unforgettable as it was unlikely.

    regards, Bruce

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