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    Re: Ocean Navigator March/April 2017 Nav Problem
    From: John D. Howard
    Date: 2017 Feb 11, 07:48 -0800


    I think one of the problems is the use of LHA instead of T. You say LHA is simply the difference in longitude and is used like in a great circle problem.

    If someone is figuring the great circle from Hawaii to San Frisco they do not measure from Hawaii westward - they measure eastward. Lon 158W to Lon 122W to get a delta of 36 degrees.  I don't think a sailor would say " If i go west 324 degrees than I will be in California "

    Yes, using sine and cosine you will get the same answer just as sin(90-a) is the same as cos(a) but it is several steps removed from looking at a map and seeing San Francisco is east of your boat.

    For me, LHA has always been a source of confusion. It is easiest to think if it is AM the sun is east or that if Regial has passed your meridian then it is west of your longitude.

    John H.

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