Satgen227  A Perseids Meteor Storm ?     by GM4IHJ         31st July 1993
The BID of this msg is SGEN227 Please use that BID if u retransmit the msg

Three years ago when writing the Space Radio Handbook, it was just
possible to report the mounting evidence that Meteor Scatter Propagation
is generated by dust from Comets. Today in 1993 , the evidence is enormous
and better still, useful professional papers on the subject are being
written every day. One of the main contributors to this advance was the
1992 pass of Comet Swift-Tuttle. Several reputable observers are now
predicting that we may not have seen the last of Swift-Tuttle. They are
forecasting that somewhen between 2100ut 11 Aug 93 and 0300ut 12 Aug 93
the Earth will run through a very large meteor stream as it crosses Swift
-Tuttle's recent track.
The actual timing of the crossing of the thickest part of the meteor dust
stream is in some doubt. There is often a residual trail of dust all
around a comets orbit and we cross Swift-Tuttle's at about 0115ut 12 Aug.
But because S-T has only recently gone past some astromers believe we may
cross the thick trail just left by the comet at about 2200ut on 11 Aug 93.
To a Northern hemisphere observer near latitude 51N at 2200 local time (
Standard Sun time not Summer time ) Eg for UK 2300 BST 2200ut 2200gmt, the
Perseids radiates from a point in the sky at Azimuth 35 and Elevation 31,
by 0000 local time it is at Az 48 and El 43 and, by 0200 local it is at Az
59 El 58. The actual sky position of the radiant is Right Ascension 45 deg
Declination 57 degs. So observers down to Latitude 25 South or so, should
be able to see it. It will be dark over Europe and Asia but North American
observers will have to wait for their local sunset which may occur after
shower maximum, though radio observers in North America will have no
problem. Radio communicators or Listeners should aim their antennas 60 to
90 degrees away from the shower radiant Eg east to south east at 2200
local moving round to south east to south by 0200 local. Radio listeners
and ping counters can monitor 48.249 MHz or 62.249 MHz for European TV
carriers or pictures, but be warned some TV stations shut down at their
local midnight, so a 50MHz or 144MHz amateur radio beacon may be a safer
target although they are not as powerful as the megawatt TVs. The RSGB
Space Radio Handbook has detailed instructions (p206 to 217) for listeners
and meteor scatter communicators.
Please remember that while some optimists are predicting that the shower
may be the greatest ever seen, and could be strong enough to damage a
number of earth satellites, this may not prove to be the case.If it occurs
under clear skies , it could be a marvelous spectacle . If skies are
cloudy or the peak occurs during your daylight hours , it could still be
the best ever Radio Observed Shower, and last but not least. There are
records of previous super showers ( Leonids 1866 ) when the stream of
meteors out in space approaching and receding from the Earth was visible
as a diffuse glowing trail in the dark sky. If this happens northern
observers could see this trail over perhaps 3 hours coming from about 10
degs south of the bright star Algol near the Perseids radiant. Southern
observers may see the receeding trail in the constellation of Triangulum
Australe RA 240 Dec -65 approx. 
Here's wishing you good listening, communicating and viewing. 73 de John
GM4IHJ @ GB7SAN