Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Re: Latitude and Longitude by "Noon Sun"
    From: Frank Reed CT
    Date: 2005 Jun 6, 22:49 EDT

    George H wrote:
    "It certainly does. It extends the Noon sight to a  protracted series of 9 to
    13 observations extending over 40 to 60 minutes  around noon. Can this still
    be described as "a noon-sight"? "
    It can  easily be as few as five or six sights. Whether you call it "noon
    anything" is  up to you. But clearly this method is only a minor extension of
    what one does  for a normal noon latitude sight. And the beginners I've explained
    it to seem to  find no particular difficulty with this description. That is,
    they "see it" as a  noon sight.
    "Frank's proposal, though the best way to do the job  of finding longitude
    around noon, is quite a protracted operation. On how  many lightly crewed
    small craft can a crew member be spared for a period of  40 to 60 minutes
    around noon each day while he takes such a series of shots  at 5-minute
    No, it is NOT a protracted operation. There is  no requirement that the
    sights be taken every 5 minutes like clockwork. Every  "five or ten" as time (and
    interest!) permit. As for the suggestion that someone  has to give up 40 or 60
    minutes of their day, gimme a break. It takes about a  minute to take and
    record each sight. You could easily make --and eat-- lunch  during that time
    taking a break every five or ten minutes for a quick sun  sight.
    "There may be some interesting implications in what Frank  is saying here.
    With this method, he is teaching a way of finding lat and  long that is only
    available if the Sun happens to shine around the moment of  noon. That's the
    position navigators were in prior to Sumner, when if they  lost their noon
    (or near-noon) observation, both lat and long were  unavailable until the
    next sunny noon."
    First, this is inaccurate  historically. Sumner's discovery was considered an
    "exotic" sight method for  decades. It was rarely used in practice. Well into
    the twentieth century, many  vessels were navigated by traditional noon
    latitude and afternoon/morning time  sight.  But back to your main point -- yes, of
    course, this method is  limited to those days when it is clear or partly
    cloudy around noon. But so  what? Celestial navigation is NOT a primary method of
    navigation any longer.
    "So I ask; is he also teaching intercept methods to those same  students?
    Perhaps (though I hope not), at Frank's institution, the revolution  in
    navigation, which occurred with Sumner and Saint-Hilaire, has already  been
    Let me clarify first that I am not formally  affiliated with any
    "institution" at this time, and I have only informally  taught the little method I've
    described. I have informal connections with Mystic  Seaport in Mystic, Connecticut
    (and have been employed there on and off in the  past), and I do occasional
    programs there. But I can tell you exactly what is  taught there for celestial.
    There is a standard 8 to 10-week course on celestial  navigation using H.O.
    229 with Sue Howell's Practical Celestial Navigation as  the course book (this
    book was written by Sue based on her direct experience  with these classes in
    the 1970s). There is also a one-afternoon class on  latitude by noon sun,
    which will perhaps be extended soon with the method for  longitude I've described
    if we can hone it down to short enough instructions. Of  those two classes,
    the noon sun afternoon fills up with eight or ten students  once every four
    months or so. Presently, the full length class draws rarely more  than two or
    three students once a year. Twenty-five years ago, the full  length celestial
    class filled to capacity three or four times a year.  People are still genuinely
    interested in celestial navigation, but since it is  not a primary method of
    navigation today, they are much less likely to set aside  the time and effort
    required for a full length course. Unless, of course, they  are hard-core
    enthusiasts like most of the people on this  list.
    "Does he teach how a position line can be obtained from any  altitude of any
    celestial body, at any time, all in exactly the same way,  from an assumed
    Personally, I am willing to teach whatever  the market will bear.
    "If all that has been lost (and I hope  it
    hasn't), it would be a very crippled 19th-century navigator that  would
    emerge from the course."
    Just to be clear,the method I have  described for getting lat and lon by noon
    sun was NOT used in the 19th century.  It is a modern method. Short, easy to
    teach, easy to learn, easy to RE-learn in  one sitting, and requiring no
    special tables beyond four or five pages of basic  almanac data which would be
    valid for decades. It is not a cheat. It is not  "fake" celestial navigation. It
    does have some limitations, as do all methods of  celestial navigation.
    As for your use of the words "crippled" and "poor" and so on, your are
    engaging in shameless exaggerration.
    "I ask nav-L members if they  would be happy to cross on ocean, without GPS,
    with a "navigator" who had  learned his craft in that way, and was unable to
    handle any other  observations than those of the Sun at noon."
    Without GPS?? If my GPS  fails, I certainly hope that someone onboard has had
    the common sense to bring a  handheld unit. NO ONE is dependent upon
    celestial navigation except for their  own amusement (=challenge, enthusiasm,
    pleasure, etc.).
    42.0N  87.7W, or 41.4N 72.1W.

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site