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(meteorobs) Celestrial Math Help Needed
Howdy,
Here's a possible new thread. Recently, three of we radio amateurs were
conducting a meteor scatter schedule one morning; the locations of we three
are:
Lat Long City/State
Maarten: 41.9015 -71.47260 Lincoln, RI
Steve: 42.27480 -71.74790 Shrewsbury, MA
Shelby: 37.6875 -85.84510 Elizabethtown, KY
Maarten and Steve (myself) were transmitting simultaneously on 144.157 MHz
using high-speed morse code (1000 words per minute) while Shel was
listening. Shel heard two strong meteor reflections; first from Maarten,
then from myself. The time between the start of Maarten's reflection and
the start of my reflection was about 0.706 seconds. Further, however, there
was a great difference in the time duration of the reflections heard from
Maarten and myself; Maarten's reflection lasted about 0.072 seconds, while
my reflection lasted about 0.35 seconds. The durations of these reflections
are estimated based on similar signal strengths. Initially, because of the
great difference in the length of the signal reflections, it seemed to me
as if Maarten and I were heard by Shel on two separate meteor reflections.
However, the distance between the homes of Maarten and myself is only about
46 kilometers as compared to a direct path between Maarten/myself to Shel
of roughly 1300 kilometers.
If I assume that one meteor illuminated the sky halfway between Shel, and a
line drawn between Maarten and myself, then it seems to me that such a
single meteor would travel only half that distance, or about 23 kilometers,
during the total time from the beginning of Maarten's and the end of my own
reflections. And that total time was about 1.09 seconds from start to end.
So this might indicate, were the meteor actually located halfway between
Kentucky and New England, that the apparent speed of the meteor was roughly
23 kilometers per second. This seems very slow, particularly considering
the frequency at which the reflections were heard of 144 MHz, where it is
generally thought that meteor entry speeds need to be several times faster,
particularly for such strong signal reflections as Shel recorded.
There are several other considerations, however, such as the field of view
of all three of us, which was somewhat different because we all were using
antennas with varying beamwidths. And then, too, is the question of whether
the meteor's path was perfectly oblique to the direct path between Kentucky
and New England.
Anyway, I'd like to discuss this further with someone who has a better
understanding of the physics involved. Any volunteers? We three are willing
to conduct further experiments of this type (essentially bistatic CW radar
analysis of meteor entries), and there is also the possibility of others
becoming involved.
Clear skies,
SteveH
Shrewsbury MA
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