[meteorite-list] ANOTHER QUESTION

[Chris Peterson]

Sterling-

What began with a single camera in Czechoslovakia in 1958 continues 
today as the European Fireball Network, and has been in pretty 
continuous operation. In addition to Pribram (not Pribeam), it also 
tracked Neuschwanstein in 2002, resulting in the recovery of at least 
three pieces. Not all networks shut down.

The original Canadian and American efforts failed due to high costs 
because they were film based, and required continuous active 
maintenance. The Czech network was also film based, but I assume the 
economics of its operation during the Cold War were different than in 
the west.

Modern networks are on the rise. We've had ours running over five years 
now. Sandia has one. There are a couple in Canada. More individuals are 
setting up one or two cameras. Video and computers is what makes this 
possible- it is no longer expensive to run a network. You no longer have 
to send a slave... I mean grad student out every day to change the film 
in several stations. No manual processing, practically no work at all. 
You don't need radar or spectrographs.

We still don't have a recovery (although one is inevitable), but I've 
recovered the orbits for a good many fireballs. Not surprisingly, most 
all come from the Zone. But a handful don't.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
To: "Gerald Flaherty" <grf2 at verizon.net>; "Chris Peterson" 
<clp at alumni.caltech.edu>; "Jeff Kuyken" <info at meteorites.com.au>; 
<meteorite-list at meteoritecentral.com>
Sent: Monday, November 20, 2006 11:31 PM
Subject: Re: [meteorite-list] ANOTHER QUESTION


> Hi, Gerry, List,
>
>
>> WHERE DO THEY
>> COME FROM...???
>
>    Despite having so many meteorite falls
> observed, we have not enough information
> from even many observations to determine
> orbits for them. For that, you need a network
> of full time observing stations with recording
> radar and automatic cameras running all night
> and spectrographs... expensive and elaborate.
>    There have been such networks set up in
> the past, but were eventually shut down due
> to great cost and limited results. The first such
> network was set up in Czechoslovakia and, in
> 1959, tracked the recovered PRIBEAM. It had
> aphelion at 4.05 AU (the Hilda family of asteroids)
> and perihelion at 0.79 (Venus) with eccentricity of
> 0.674. In all the other years this network ran, it
> only successfully tracked one other item, an iron
> which hit German forest country and was never
> recovered.
>    In the 1970's the Prairie Network in the USA
> was established, which tracked and led to the
> recovery of LOST CITY. Although it tracked
> another dozen or so re-entries that probably
> brought in a surviving chunk, none were ever
> found. LOST CITY had an aphelion of 2.42
> AU (densest past of the Zone) and a perihelion
> of 0.97 AU (the Earth) with an eccentricity of
> 0.417. It too was shut down due to "costs."
> And the Canadian network (MORP?) tracked
> INNISFREE to recovery, but never recovered
> another.
>    All three of these spacerocks had aphelia
> deep in the asteroid zone, all at places where
> Jupiter could strongly perturb them. The great
> meteoriticist Krinov worked out a pretty good
> orbit for Sikhote-Alin that showed it came from
> the Zone. The Great Grazer of 1972 (the Jackson
> Hole Bolide) had several orbits worked out, but
> all of them have it coming from the Zone.
>    Face it, it's a bad neighborhood! It's like, they're
> standing on an overpass and dropping rocks onto
> the windshields of passing planets! Of course,
> three examples of well-determined orbits are hardly
> "proof" when there are many thousands of meteorites.
> But on the other hand, if you rolled three sevens in
> a row at craps, wouldn't you be surprised? (And,
> if you CAN roll three sevens in a row at craps, we
> need to talk...)
>    So, we blythely assume most of them come from
> The Zone. (My apologies for calling the Great Grazer
> a "bolide," but magnitude -25 or -26, hey! You need
> a special name! Especialy since it was nice enough
> to miss us...)
>
>
> Sterling K. Webb