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    Re: Latitude and Longitude by "Noon Sun"
    From: Frank Reed CT
    Date: 2005 Jun 6, 22:58 EDT

    Robert E wrote:
    "An old friend of mine, who  passed away a few years ago, and who was an
    experienced navigator for over 60  years, once told me that the noon sun shot
    was overrated; that all you had to  do was to take a few shots with an
    interval of 2 - 3 hours then transfer one  of the LOPs."
    
    Absolutely. IF you have learned a general method of  intercept/LOP celestial,
    then ALL of the traditional sights (latitude by  Polaris, Noon Sun, latitude
    by double altitudes, etc.) are irrelevant because  they can be treated just
    like any other sight. And btw, your late friend is not  alone in this belief.
    It's an idea you'll find repeated in a fair number of  navigational texts, too.
    
    The advantage of this Lat/Lon by Noon Sun  business is that it's very easy to
    teach, learn, and re-learn, and requires an  absolute minimum of equipment
    and books. A navigation student who has been away  from practice in navigation
    for ten years may not remember how those tables work  anymore, but you can pick
    up Lat/Lon by Noon Sun in a few hours and have a  decent celestial fix at the
    very next noon.
    
    And:
    "Mind you the noon  sun shot is fun to do and very simple to calculate. For
    this reason, it  should remain as one of the basic mainstays of
    astro-navigation, however,  taking and reducing a sun shot at any other time
    is painfully easy with  calculators and with HO 249 (AP3270 in Britain and
    Canada)."
    
    Tell me  then, if it is so easy, why doesn't everybody do it?? I'm not
    kidding. I have  observed many students learning celestial and they tend to come
    from  wide-ranging educational backgrounds and skill sets. For many people, it's
    all  just damn confusing. I helped out a couple of years with a class in which
    one of  the students was a skilled, highly-paid surgeon. And he couldn't make
    heads or  tails of celestial navigation. His wife, however, loved it and
    understood  everything.
    
    And:
    "George has a very good point about crossing the  ocean without GPS and with
    someone who only knows how to take a noon  sight."
    
    Where is this world where one crosses oceans without GPS? Are you  concerned
    that yours might break down? The best backup for GPS is another GPS.
    Celestial navigation is no longer a primary method of navigation. There are  plenty of
    people who want to do it for fun and challenge and maybe, just maybe,  for a
    backup in case something happens to the main GPS *and* the various spare  GPS
    receivers. There are others who do it for various certfications. But why
    else? Wait, wait... I've got it! You're at war with another maritime power. You
    are engaged in a naval battle and the other vessel surrenders. You send an
    officer aboard to take your prize into port and discover that the enemy crew
    have thrown overboard the ship's GPS receivers! How will you ever get your prize
    back to port. Sure, you can borrow one of the three spare GPS receivers from
    your own vessel, but what happens when you have captured two or three other
    enemy vessels?? That is when you will need your sextant and celestial
    navigation! (in case you don't recognize this, it is a rewording of a excuse for
    studying 'longitude by lunars' from the late 19th century which I posted to the
    list a while back).
    
    And:
    " This is something I harp on
    when  discussing GPS with the uninitiated. The argument that some students
    will be  detracted from learning astro-navigation if things become too
    complex has  merit, however, my response would be that I would not bother
    wasting my time  in trying to train someone who is not committed to learning
    it properly. No  pain, no gain."
    
    Well sure. You can do that. Consider an alternative: even  the most
    enthusiastic students will enjoy being able to get a good position fix  on the first
    day of class. So teach lat/lon by noon sun, and then move on. If  some students
    decide that the rest isn't for them, they at least will take away  one method
    of celestial navigation that actually works and gives a real fix. The
    students that stick it out will have something to fall back on if they are  missing
    one of the elements of intercept/LOP navigation when the day arrives  that they
    actually want or need to do celestial.
    
    And concluded:
    "I  won't delve into the "what ifs" (what if my watch went overboard  etc.)."
    
    If you're willing to entertain the highly unlikely possibility  that you
    might cross an ocean without GPS, then dropping your watch overboard  seems like a
    sure thing! 
    
    -FER
    42.0N 87.7W, or 41.4N  72.1W.
    www.HistoricalAtlas.com/lunars
    
    
    

       
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