[Prev][Next][Index][Thread]
Re: (meteorobs) further suggestion for fireball measurements
On Tue, 24 Jul 2001, Marco Langbroek wrote:
> 2) azimuth and altitude of that point of extinction.
>
> In addition to this, it is advisable to also record, if possible, the same
> points of information (angle and azimuth) but then for the point where the
> prolonged fireball trail would cross the horizon. This is easy to do by
> having the eyewitness stretch out a cord along the trail path. This
> information actually might give best and most straigthforward results.
I agree that that this is important information to collect and the idea
of using a cord held between two hands probably better than what I used
to do. I'd have the eyewitness hold a straight stick in one hand, but they
would invaliably start by orienting the stick in the 3D direction that they
had perceived the fireball to travel in. This tended to be more or less
close to the actual trajectory (for reasons I've given on meteorobs several
times), but is of no use in the analysis as the perceived 3D direction
involves both physical and psychological components that are unmeasurable.
By using two outstretched arms, the eyewitness would be constrained to
indicate the great-circle arc. Actually, this proceedure can be done for
several points along the trail (Az, El, zenith angle), although I agree with
Marco that the data for the end point is more reliable.
Cheers, Rob
To stop getting email from the 'meteorobs' list, use the Web form at:
http://www.tiacdot net/users/lewkaren/meteorobs/subscribe.html
References: