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: Sumner lines
    From: George Huxtable
    Date: 2001 Feb 17, 5:08 PM

    Peter Smith wrote-
    >Apropos the current discussions of ex-meridian sights and books on the
    >longitude problem...
    >Can anyone recommend any articles, books, or parts thereof that chronicle
    >the gradual change in common practice from separate solutions for latidude
    >and longitude to LOP-based methods, first Sumner's, then altitude-intercept
    >after Saint Hillaire? Neither _From Sails to Satellites_ nor _The
    >Haven-Finding Art_ cover this. All I have been able to gleen is inferences
    >from the way the topics are treated in various editions of Bowditch. It
    >would seem that the US Navy adopted the new methods early in the 20th
    >century, but the merchant marine continued with the old right up to WW-II.
    > -- Peter
    Yes, the book you're looking for is definitely Charles H Cotter, History of
    Nautical Astronomy, Hollis & Carter, London, 1968.
    Chapter 6, Methods of finding longitude, and 7, Position-line navigation,
    together make up nearly half of a 400-page book. So you will find all the
    detail you need, and maybe more than you bargained for. With masses of
    stuff on lunars, if that interests you. Not easy reading though: Cotter
    knows his trigonometry, and doesn't stint on the maths. I find it very
    thorough and satisfying, though Steven Wepster in a recent mailing was less
    Not easy to find, though. I had a search out for it for several months on a
    couple of websites for secondhand books. Eventually it appeared on Abe
    books at US$100. Of course, the way these things go, just after I had
    bought it a second copy turned up at less than half that price! It was
    several months ago now, but that copy may still be available. Try a search
    on Abe books. Good luck.
    George Huxtable.
    George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    Tel. 01865 820222 or (int.) +44 1865 820222.

    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