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    Re: Celestial Navigation without a sextant.
    From: Peter Fogg
    Date: 2008 Mar 8, 17:43 +1100

    I was just sitting here using my calculator to do this as Paul's
    suggestion arrived.
    It seems fitting to assume that 40 South is at that latitude, and have
    assumed E152d of longitude, in a small boat from which the sun is
    observed from an elevation of 3 metres.
    Tomorrow 9 Mar 2008 sunrise is observed at 05h 43m, and sunset at 18h
    21m (local time).
    If the position was S40d 00'  E153d 00', then sunrise at 05h 38m and
    sunset at 18h 17m (your mileage should NOT vary).
    So the answer is yes; with the accurate time longitude can be
    calculated via observation of sunrise and sunset.
    On Sat, Mar 8, 2008 at 5:20 PM, Paul Hirose  wrote:
    > 40 South wrote:
    > > Supposing one was in a small boat with an accurate timepiece and the
    > > necessary tables, how accurate could you determine your longitude by
    > > observing the rising or setting of the sun or any other celestial
    > > body?
    > You could run an experiment using one of the online calculators at the
    > U.S. Naval Observatory site. Enter a latitude and longitude (some
    > convenient integer number of degrees) and note the calculated time and
    > azimuth of sunrise. Then try changing the latitude or longitude by one
    > degree and see how much difference it makes.
    > http://aa.usno.navy.mil/data/
    > The third link down is probably the best for this.
    > --
    > I block messages that contain attachments or HTML.
    > >
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