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    Re: My first Lunar
    From: Jeremy C
    Date: 2008 Jul 15, 22:32 EDT
    Frank wrote:

    Having a good DR position is convenient but not necessary when it comes to
    clearing a lunar. Of course if you want to assess the accuracy of the sight,
    then you want the actual position and correct GMT as nearly as possible. You
    can figure out where you are, more or less, by trial and error from your
    sight data. Go to the calculator on my web site, set the GMT of the sight to
    22:19:30 and set your DR Lat to 14d 31'N and your DR Lon to 61d 38.1W. That
    nearly matches your sights, lunar and altitudes, too. So assuming your
    observations were good (and I would bet they were) you were probably about
    30 miles west of Martinique. Does that fit your recollection?
    ---------------------------------------------
     
    Jeremy replies:  I remember it being around there only because I was sailing as a 3rd assistant engineer (read no real day to day knowledge of where we were) on a training ship heading down the Caribbean.  Given the date, about 2 weeks into the voyage, I was only guessing at where we might be.
     
    I do remember being surrounded by cadets looking at me strangely as they collected their star sights as I was shooting lunars.  None of them had the first clue what I was doing, and frankly, neither did I.  I also recall taking about 40 minutes in my stateroom with Bruce Starke's tables to reduce this one sight.  I was able to cut that down with practice, but the complexity of the tables soured me on lunars for many years.  I will attach the work form in a day or two.
     
    I recognize that I could figure out about where I was by the altitude observations, but here is a good exercise for an old-school lunar where position and time are only approximate.  I do have the actual UTC of the sight, but I will reserve that knowledge for a few days to let the folks on the list play with it.
    -----------------------------------------------------------------------------
    Frank continues:

    Now as it happens, this is yet another one of this miraculous lunar sights
    where you can do the clearing without using any spherical trig. If we take
    the pre-cleared altitudes and distance (the altitudes of the objects'
    centers and the center-to-center lunar distance) and add them up, we get
    nearly 180 degrees. So adjust the Moon's altitude higher by about 24 minutes
    of arc and then work it AS IF they were exactly opposite each other in the
    sky.
     
    -------------------------------------------
     
    I am good with these miraculous Lunars no? LOL
     
    Jeremy




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