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(meteorobs) Greenville SC Fireball image captured 8-6-01 ~2230pm EST
Rob, I am passing your calculations on to the
'meteorobs' email forum. If the original eyewitness
doesn't report this fireball sighting, I urge you to
report your calculations as the next best alternative.
Use either of the following forms:
http://www.amsmeteors.org/fireball/report.html
Or for print-out and postal mailing, or to cut&paste
into an email:
http://Web.InfoAvedot net/~meteorobs/fireball_form.html
NOTE: Rob is not a 'meteorobs' subscriber. If you
follow up, please be sure to MANUALLY put
<ROBERT.D.MATSON@saic.com> in the "Cc:" line of your
reply!
Bob V.
- ------- Forward Message
[meteorite-list] Fireball image captured 8-6-01
Matson, Robert <ROBERT.D.MATSON@saic.com>
Tue, 7 Aug 2001 10:31:23 -0700
Hi All,
Regarding the meteor image captured on digital camera,
Bernd wrote:
> What a pity it wasn't taken with a fisheye lens
> showing a 360 unobstructed sky view. I wonder if it
> was an early Perseid or
> just a sporadic meteor. The constellation Perseus
and
> the Perseid radiant had already risen low in the
> east-northeast
> and tracing its path backwards leads to the general
> direction of Perseus.
One question I have is which way was it going? Did
Scott's image capture the beginning of the trail or
the end? His statement, "the brightest meteor I ever
saw came over my shoulder and I captured part of it"
could mean either direction (though I suspect he meant
from in front of him to behind him). Based on the
gradual change in the trail brightness, I'm assuming
he caught the beginning, and that the end is out of
the frame. If so,
I've extracted two coordinates from his image in case
anyone wants to plot the track to determine if it
intersects a known radiant.
The track ends (I assume) in Sagittarius at local
coordinates ~azimuth 181.5, elevation 31.5d, with a
SSW heading. The track also passes very close to mag
3.85 alpha Scuti (the brightest star in the trapezoid
in the upper left corner) at roughly RA 18h 36.5m, Dec
-8.3d.
So the track was heading toward Aquila followed by
Sagitta, and would later intersect Cygnus, splitting
eta- and epsilon-Cygni.
> A Kappa Cygnid? Probably too early! This shower
> produces only a few meteors per hour, but some of
> them are flaring fireballs
> and the time would fit: early evening hours with the
> radiant in NW Cygnus nearly overhead.
The track looks like it would pass at least 10-15
degrees southeast of kappa (and of course, the meteor
would need to have been going in the direction I'm
assuming).
> The Delta Aquarids also come to mind with a radiant
> near RA 22h 36m
> and a declination of -17=B0. They have a double
> radiant. Radiant #2 lies just north of the above
> coordinates, on the celestial equator.
Can rule these out -- too far off track in either
direction.
> Harold Povenmire's famous Upsilon Pegasids peak near
> Aug 8, but he describes them as rather faint,
> typically 3.5 mags, and leaving no trains.
>
> Well, Mars was magnitude -1.4 on that date, and
> Antares is about 0.96 (about 4 cm to the lower right
> in the 4 o'clock position),
> so I would guess its brightness was about -1 to -2.
Given that Mars and the rest of the stars are
stationary during the exposure, and the meteor was
probably travelling at at least 15 degrees/second, the
meteor's effective exposure time on any one pixel was
probably less than 1/100th of a second. Compared to
the 60-second exposure, that represents a dimming of
over a factor of 6000, or more than 9 visual
magnitudes. Given that a Mars-sized piece of the
track appears to be comparable in brightness to Mars
itself (though the image is probably saturated), the
meteor had to be at least as bright as -10.
Cheers,
Rob Matson
References:
http://www.pbase.com/image/227663
<http://www.pairlistdot net/pipermail/meteorite-list/2001-August/004825.html>
<http://www.pairlistdot net/pipermail/meteorite-list/2001-August/004844.html>
- ------- End of Forwarded Message
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