[meteorite-list] Image of PA/MD bolide passing near M31

From: Rob Matson <mojave_meteorites_at_meteoritecentral.com>
Date: Sun, 12 Jul 2009 00:02:07 -0700
Message-ID: <GOEDJOCBMMEHLEFDHGMMMEDHDNAA.mojave_meteorites_at_cox.net>

Hi All,

At first I was inclined to believe that the telescopic image recorded
by amateur astronomer Mike Hankey [for South Park fans please note
that I resisted the urge to refer to Mike as "Mr. Hankey" ;-) ] had
to be showing an aircraft rather than a bolide, as Dean Bessey first
theorized here. However, there are some problems with the airplane
theory, most notably the increasing separation between the trails
as you move from the top of the image (higher elevation angle) to
the bottom of the image (lower elevation angle). The trail separation
increases by more than 20% over the tiny field of view, which for
an aircraft would require the plane to be flying almost directly
toward or away from the observer. This cannot happen for an aircraft
flying anywhere close to level flight.

For those trying to track down potential meteorites from this
fireball, I hope you haven't been depending too much on the azimuth
and elevation information provided by J. Kelly Beatty of S&T. While
he (she?) correctly matched up the image's pointing and orientation
with the star field surrounding M31, the coordinate grid that is
overlaid is very wrong for some reason. The telescope wasn't pointing
at elevation 62 degrees. From the Baltimore area, the Andromeda Galaxy
is much lower in the sky at 1:06 am on July 6th -- about 27 degrees.
The object track at the top of the image passes very close to the
9.3-magnitude Hipparcos star #003223, which was at azimuth 57.0,
elevation +27.5 at 1:06 am. When I have some more time, I'll calculate
the 3D trajectory from this single frame, since there is enough
information in it alone to do so. Suffice to say that the object
was almost certainly travelling from NE to SW, heading toward
Baltimore from the NE but not quite making it there.

--Rob
Received on Sun 12 Jul 2009 03:02:07 AM PDT