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    Re: My first Lunar
    From: Giuseppe Menga
    Date: 2008 Jul 16, 05:48 +0200

    Dear Frank,
    using my clearing algorithm I found:
    time 22:19:38 GMT, pos 14�N 35.3', 61�W 41.3'
    LD 68� 13.13' (sextant LD 68� 19.40')
    The position is roughly 5 miles from yours
    Giuseppe
    ----- Original Message ----- 
    From: 
    To: 
    Sent: Wednesday, July 16, 2008 4:03 AM
    Subject: [NavList 5852] Re: My first Lunar
    
    
    >
    > Jeremy, you wrote:
    > "Well I found my first lunar, and it will be tricky.  Here's the data that 
    > I
    > have.
    >
    > GMT Date is 26 January 1999.  GMT of the sight was about 2220.  Dip
    > correction is -7.7' of arc.  The lunar was at evening twilight and a near
    > limb observation between Jupiter and the Moon was taken.  The sextant LD 
    > is
    > 68deg 19.4'  IC is 0.0'.  An upper limb altitude of the moon was taken HS 
    > is
    > 66 deg 09.3'  The Hs of Jupiter is 45 deg 22.3.
    >
    > Here's the rub:  I have no idea where I was other then to say I was 
    > probably
    > somewhere in the Eastern Caribbean.  Best guess is about 20 deg North
    > Latitude and 70 degrees West Longitude."
    >
    > 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?
    >
    > 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.
    >
    > -FER
    >
    >
    >
    > >
    > 
    
    
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