(meteorobs) Determining physical dimensions of a large fireballin the sky?

[Mike Hankey]

Chris,

Thanks for the reply and info. I understand about the dark flight, but
its also my understanding that the dark flight model is tied to the
trajectory / ground track. I also understand the ground track can only
be as good as the field research that is done on the original videos.
So at this point my strategy is improving the ground readings so we
can improve the trajectory and then the dark flight model. I believe
for this fall the radiosonde data has been collected and is being used
in the current projections. (problem is we've searched the heck out of
the current area and are still coming up with nada).

Unfortunately we do not have video from the all sky meteor cams but
rather security tape and amateur footage. It sure would be nice if the
whole country or world was covered with these all sky cams (i'm
planning on adding one at my house for next time).

For the fall I'm working we have a total of 10 recordings: 2 direct
video recordings, 3 use-able shadow recordings, 4 flash of light
recordings and 1 photograph. Up to this point the direct sighting
recordings were not calibrated / they were more eyeballed with low
quality copies of the videos. And none of the work to measure the
shadows was ever done. (that's next on my list after completing the
stellar calibrations.) My thoughts were, if I could put in the time to
properly do the field work it would improve the trajectory and dark
flight model (probably a pipe dream, but I'm running out of options
and time).

Thanks,

Mike

On Tue, Oct 13, 2009 at 11:48 AM, Chris Peterson <clp at alumni.caltech.edu> wrote:
> Mike-
>
> Even if you know the fireball trajectory with high precision, this doesn't
> usually get you very close to a landing location. That depends primarily on
> the winds experienced by material during dark flight. That effect can be
> significant: a meteorite strewn field can lie in front of, to the side, or
> behind the point of retardation (or terminal explosion). The deviation can
> be miles. It is critical in analyzing any fireball with the intent of
> locating meteorites to obtain data for the most recent local radiosonde
> launch providing wind speed and direction at high altitudes. Otherwise,
> there is no way to accurately estimate the landing area.
>
> Chris
>
> *****************************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
>
>
> ----- Original Message -----
> From: "Mike Hankey" <mike.hankey at gmail.com>
> To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
> Sent: Tuesday, October 13, 2009 9:30 AM
> Subject: Re: (meteorobs) Determining physical dimensions of a large
> fireballin the sky?
>
>
>> Pat,
>>
>> I would be very interested in seeing your spread sheet for calculating
>> the trajectory and landing locations, even the simplified version.
>> I've been working a fall in PA and I've recently been calibrating the
>> original videos by re-shooting stellar objects from the same cameras
>> (its turning out great).  I've gotten much better ALT AZ readings from
>> them after doing the calibration. Your xls sounds very interesting to
>> me and re-working the ground path is next on my list of things to do.
>
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