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    Re: A Cook-esque Lagoon lunar
    From: Peter Hakel
    Date: 2010 Apr 7, 23:38 -0700
    1) 2.6 nm
    2) 24.1'
    3) 3:48:08
    4) S   6 deg 07.7'   (-6.128)
        E 72 deg 26.8'   (72.447)

    Please see the attached Google Earth screenshot.  The longitude looks OK for Diego Garcia but the latitude came out too far north…

    Peter Hakel

    From: "Anabasis75@aol.com" <Anabasis75@aol.com>
    To: NavList@fer3.com
    Sent: Wed, April 7, 2010 7:43:41 AM
    Subject: [NavList] A Cook-esque Lagoon lunar

    In celebration of the recent thread about the 155 degree lunar in the South Pacific, I offer this lunar observation.
    Standing data: Height of eye 106 feet, index correction -0.8', Temp 88 deg F, Pressure 1010.8 MB.  Speed 0.0 (at anchor). DR Latitude is 7 degrees South, Longitude 72 degrees East.  Date is 5 April 2010.  Hour of observation is between 0900 and 1000 Local.  ZD -6.
    Our intrepid navigator is anchored in the lagoon in Diego Garcia.  To the east the sun is rising, and fortunately, with 106 feet Height of Eye, allows us to see over the palm trees at that azimuth to measure the sun on the sea horizon.  Unfortunately at the moon's bearing, the sea horizon is obscured by land.  The moon can be observed using the waterline of the deep-draft pier.  Fortunately for us, there is a radar tower on this pier at a known height of 120 feet over sea level. 
    Using his trusty sextant with an index correction of -0.8' he observes the angular distance between the waterline and the top of the tower.  The sextant angle is 0 degrees 26.9' of arc.  What is the approximate distance off of the shore and what is the calculated dip short of the horizon for the moon observations?
    After finding the dip short numbers, our navigator takes some altitudes and a series of lunar observations.
    Sun LL Hs 36-39.4'
    Moon UL Hs 38-06.2'
    Ds  104-03.2'
    Ds  104-03.8'
    Ds  104-02.3'
    Ds  104-02.2'
    Sun LL 38-07.0'
    Moon UL 36-51.1'
    1) determine the distance off of the tower
    2) determine dip short of the horizon for the moon observations
    3) Determine GMT and Longitude by lunar distance
    4) determine position.


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