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Re: Meteor Velocities
I have read most of the "Meteor Velocities" thread, but not all. Please forgive
me if what I am about to say has been said elsewhere.
An important point to remember when estimating meteor velocities is that the
estimate is, at best, an apparent estimate. The true speed of a meteor can not
really be appreciated unless that meteor is moving perpendicular to an
observer's line of sight. Two observers separated by 100 miles or so can come
up with different velocity estimates for the same meteor. For instance, if one
observer saw a Perseid and said it traveled 50 degrees westward in one second,
that would be considered a fast meteor. If another observer was about 100 miles
west of the first observer (don't check my math on this guys, this is only an
example) the meteor would be heading more toward him, thus the meteor path
would be more foreshortened. The result would be that this second observer
would see the meteor for one second, but it might only traverse 10 degrees of
sky. A meteor traveling 10 degrees in one second would be relatively slow.
Now for major meteor showers, the above doesn't really matter, because the
discussion was, at least to some extent, referring to helping to spot shower
members, and it is fairly easy to identify the radiants for short-trailed
meteors. But the problem does become important when minor radiants or new
radiants appear. Meteor observing can be fun, but it is unfortunate that more
people do not plot what they see (I don't all of the time). Therefore, for an
observer to recognise suspicious activity something has to catch his/her
attention and this will frequently be similar apparent velocities. It would be
quite possible for a minor radiant (previously known or not) to be recognised
by one observer, but not by another located some distance away, even though the
same meteors are seen.
Gary