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    Re: Cugle - longitude at sunrise and sunset
    From: Gary LaPook
    Date: 2013 May 2, 23:21 -0700
    You  only found one book pre-1937 that mentions the approximate method for determining longitude by sunrise, that is Cugle because Dutton (1934 ed) does NOT show that method. Cugle is for marine navigation and doesn't recommend this method for flight navigation and it does not have the special refraction and dip tables necessary for use in flight. The NIF is after the Earhart flight and even the NIF says for EMERGENCY use. What kind of emergency? Well not fire or engine failure or a zillion other emergencies you might think of. The only emergency this applies to is lack of an octant because with an operable sextant you can get much more accurate position information. Noonan had an octant. Neither NIF nor Cugle use you method of computation. You have never produced any navigation manual or textbook that uses your computation method so you must take great pride in developing such an original method. Of course, Noonan had never heard of it since you developed it many years after he was lost.

    --- On Thu, 5/2/13, h.a.c. van Asten <hac.vanasten@gmail.com> wrote:

    From: h.a.c. van Asten <hac.vanasten@gmail.com>
    Subject: [NavList] Re: Cugle - longitude at sunrise and sunset
    To: garylapook@pacbell.net
    Date: Thursday, May 2, 2013, 6:33 AM


    True that sunset-sunrise fixes give arbitrary results , but at sunset mr.Noonan was not to prepare for finding a small island . At sunrise he was , but that does not exclude that for the two phenomena , he beforehand computed the time-position groups in case he could comfortably make use of it . From 10,000 ft altitude he could namely observe sun´s centre in the celestial horizon , sun´s image above the horizon by refraction , with the bubble sextant at sunset . There are in the mean time 3 textbooks describing the fashion : Dutton , Cugle-1938 and NIF - 1944. .
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