Hi John,
You wrote: "OK, then what do we do to compute latitude and longitude to a
hundredth of a degree?"
I had to laugh when I watched the show last night, too. To a 100th of a
degree? As if the basketball hoop's pole is not tilted at all or bent (not
to mention the litany of other sources of observational error)?!
Still the method is the same as if one is computing the length and
direction of a shadow for a given latitude and longitude. Usually we start
with lat. and long. and the shadow's length and position are unknown. In
this case, we work backwards. The lengths of the shadow and pole give you
the altitude of the sun by simple trig. On a given date, the sun will
have this altitude twice (morning or afternoon). We know the date and
approx. time from the camera. The date allows us to look up the sun's
declination. The declination with the calculated solar altitude, will give
you the information needed to determine latitude. We can also find the
local solar time of the event. Corrections for the equation of time will
offer us mean clock time at that location. If the camera's time stamp
were precise for that time zone (a big if), we could determine how far east
or west we were of the center of the zone and so compute longitude.
All the best,
Sara
Sara Schechner, Ph.D.
David P. Wheatland Curator
Collection of Historical Scientific Instruments
Department of the History of Science
Harvard University, Science Center 251c
Cambridge, MA 02138
Tel: 617-496-9542
Fax: 617-496-5932
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