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    Re: Impressed with the Raft Book
    From: Brad Morris
    Date: 2010 Jan 27, 11:51 -0500

    This topic has been discussed extensively by many parties on the list, for a 
    substantial period.  The consensus of opinion is that you can generally 
    achieve about 1 degree of latitude.  Frank Reed points out that there is a 
    fish tracker that uses exactly this feature (latitude by length of day).
    The inaccuracies principally revolve around low altitude refraction of the sun 
    (just when is that sunrise, and precisely when was that sunset) and the 
    declination of the sun (this function breaks down as the declination of the 
    sun approaches zero).  So for the case indicated below, we are far from zero 
    declination.  Further, how was sunrise and sunset determined?  Harare, South 
    Africa is quite far from either the Atlantic Ocean for sunset or from the 
    straits between Africa and Madagascar for sunrise.    I share Christian's 
    description of this as a 'feat' and would look to further information to clarify.
    Best Regards
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