Welcome to the NavList Message Boards.

NavList:

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

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: suggestion for a satisfactory celnav narrative
    From: Bill Noyce
    Date: 2005 Jun 3, 12:26 -0400

    Perhaps the fact that "longitude by noon sun" comes up so often
    is a good reason that there *should* be a discussion of this
    method, pointing out why it is a bad idea...
    
    Is there any other observation that gives longitude without
    knowing latitude first?  Maybe this is part of its appeal.
    
    (By the same argument, the advanced version should discuss lunar
    altitudes for GMT, and what's wrong with them.  I think George's
    "parts 1-4" do include such a discussion.)
    
            -- Bill
    
    -----Original Message-----
    From: Navigation Mailing List
    [mailto:NAVIGATION-L{at}LISTSERV.WEBKAHUNA.COM] On Behalf Of George
    Huxtable
    Sent: Friday, June 03, 2005 8:59 AM
    To: NAVIGATION-L{at}LISTSERV.WEBKAHUNA.COM
    Subject: Re: suggestion for a satisfactory celnav narrative
    
    
    Andrew Corl wrote-
    
    >For Courtney, I am raising my hand to help with this.  Don't know what
    I can
    >do but here is a list of techniques I feel should be in the manual:
    >Dead Reckoning
    >Latitude by Noon Sun
    >Longitude using a shortwave radio and the noon sun
    >Sextant operation and how to determine the elevation above the horizon
    of
    >the sun, moon, star, and planet
    >Sight reduction using H.O. 249 - method I am presently learning
    >Sight reduction doing all the math (the "apex of celestial navigation"
    >according to Frank)
    
    As a world-weary old cynic, my opinion is that any offer, saying "this
    is
    how I think it should be done, and I'm prepared to contribute" is worth
    at
    least 10 proposals of "this is how I think it should be done, but by
    someone else, not by me". So Andrew's suggestions are indeed useful.
    
    No doubt, he expected a bit of nitpicking about his choice of topics,
    and I
    am happy to provide it. It relates to his suggested topic-
    "Longitude using a shortwave radio and the noon sun"
    
    Although proposals for timing the moment of noon, by observing the Sun
    around noon, reappear on this list at regrettably regular intervals, the
    fact remains that noon is the worst possible moment for doing that job.
    Although it's possible to make a crude assessment of the moment-of-noon
    by
    making an extended set of observations, before noon and after, the only
    way
    to get a PRECISE value of time-by-the-Sun (and hence longitude) is to do
    so
    at a time WELL AWAY from noon, so that the Sun is rising and falling at
    a
    measurable rate. If Andrew were to rephrase his suggestion to read
    instead-
    "Longitude using a shortwave radio and a time-sight of the Sun",
    then I, for one, would be happy.
    
    George.
    
    ================================================================
    contact George Huxtable by email at george---.u-net.com, by phone
    at
    01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
    Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    ================================================================
    
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    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