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Re: (meteorobs) Visual magnitude

> Sirko mentioned:
> >If I recall it correct I read somewhere, that the luminous trail of a
> >meteor has an actual diameter in the order of 1m. Don't ask me *where*
> >this information came from, I think it was a result of some photographic
> >investigation. It means that the apparent width of a meteor's trail should
> >be of the order of a few arc seconds.

My recollection was of a larger figure in the tens of metres, perhaps
given by Keith Hindley verbally or in an old BAA Meteor Section
Newsletter or perhaps in a paper by Baggeley.  This figure might be
for bright visual meteors.  It also surely depends on the velocity,
height, the meteoroid's `crumbliness', and other factors.  A quick
trawl through some Czech papers just now turned up a few potential
papers, but it's too late at night here to wade through papers that
take a page just to list the meanings of the symbols used in the
equations.  Can anyone provide a freindly reference?

> I'm surprised at the 1 arcminute width for trails. (Also, I wasn't sure how this 
> resulted in apparent widths on the order of arcseconds, Sirko?) I perceive trail 
> widths fairly clearly in two dimensions, especially for brighter meteors, and 
> I'm pretty sure that images subtending 1 arcmin or less wouldn't give my eye 
> this impression. Could I be witnessing some sort of optical "blooming" effect in 
> my eye, rather than actual meteor trail width?

I think Sirko was talking about 1 metre (meter in American (-:) when
he wrote 1m.  One arcminute approximately corresponds to about 30
metres in the meteor layer.  So 1 metre subtends about 2 arcsec.

As far as widths go, the visual meteors seen telescopically appear to
have width, but I don't recall seeing anything appear wider than the
moon (31'/19.5x), and most are sub-arcminute.  Some of this width is
attributable to the train, which you can see expanding and drifting
almost immediately following the meteor.  Typical telescopic meteors
that I observe don't exhibit a pronounced width.

Malcolm
References: