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Re: (meteorobs) Fwd: [Astronomer] Observation -- Possible meteorite?
Wayne T Hally wrote:
>
> The only problem with the GSOC website is that it does not list the out of
> control tumbling Iridiums. These are the ones most likely to be easily
> confused with a point meteor. I'm sure most of us have seen a normal
> Iridium...lasting 10-20 seconds, depending on how long you follow it after
> the bright flare. They also have a smooth ramp up and down of brightness,
> with a little specularity at the brightest point. Tumblers are another
> matter. They can last just a few 10ths of a second, and also have very
> sharp "on" and "off" edges to the brightness. Very point meteor like. Of
> concern as well are the dozens of other objects (mostly rocket bodies)
> which also flash, and are also not on the GSOC site. While when the object
> first starts spinning it is very rapid, making ID as a man made object
> easy, after a period of time they slow down due to gravitational and
> electromagnetic effects...hence the period can become quite long...the
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> longest I've been able to detect is about a minute. These can be very short
> flashes at nearly any brightness.
>
> Wayne
I caught an interesting long-period tumbler (during Comet Hyakutake),
over at least 10 minutes. See:
http://www.comet-track.com/hy/hy317.html
The 1st Schmidt-Camera exposure (B&W film, TechPan) is 4 min. You can
see a very faint trail near the nucleus of the comet. Then, after a few
minute delay (I had to load the film holder with color film), I started
a 4 min color exposure. You can see a *bright* trail, followed by a
faint trail (like in the B&W exposure). Apparently, this "object" was
tumbling over several minutes: faint-trail, "gap", bright-trail, etc...
I was too busy manual-guiding to notice this naked eye. (the frames are
4.5 x 6.5 deg, about the FOV of 6X binoculars).
I never found out what this "object" was. Is it a flaring satellite,
with alternating levels of flaring?
>
> > Thanx Dave, for checking that. I find that almost all poimnt meteors and
> > alleged "gamma ray bursts" are satellites now. Any point meteor report
> > should be checked against the Iridium or other flaring/flashing satellite
> > locations.
> >
Few days later on March 21 1996, I imaged the comet using the same
Schmidt Camera. One of the frames had a bright trail with periodic
closely-spaced point-like "flares". It wasn't a plane.
The comet in 3/96 was somewhat near the celestial equator, so I guess I
was shooting in the area where satellites abound. Other
astrophotographers have mentioned how shots in this area, always catch a
lot of satellites.
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