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Re: (meteorobs) meteor duration estimates
George,
You commented:
>For those who estimate meteor durations for whatever reason...
The "whatever reason" is the ability to gain a general approximation of the
meteors angular velocity from the observer's data, that is, distance
traveled (in degrees) over the duration (in seconds).
how do you come
>up with these estimated times?
In collecting data for the AMS, the observer estimates the duration of the
meteor to the nearest 1/10 second. Making good estimates is an acquired
skill, and one which can be practiced while not in the field. When I was
visually observing, I used the stopwatch feature on my wrist watch to
accomplish this. I would pick some time between 0.2 and 1.5 seconds and
practice starting and stopping my stopwatch in this time interval (+/- 5/100
seconds). After a lot of practice I would randomly pick durations and try
to start and stop the stopwatch in that interval with only one try. If a
meteor's duration in the field was greater than 1.5 seconds, I recorded the
duration only to the nearest 1/2 second.
As with estimating meteor magnitude and path length, estimating duration is
a practiced skill wich improves with experience. Novices may have only 1/2
second accuracy, but seasoned observers probably have an accuracy of about
+/- 1/10 second. Very fast meteors that could not be estimated are recorded
as being less than the observer's "threshold," such as < 0.2 seconds. I
eventually became confident in my ability to gage between 0.2 and 0.1,
although I could never start and stop my stopwatch in less than 0.12 second.
Take care,
Jim Richardson
Graceville, FL
Richardson@DigitalExpdot com