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
    Current Bowditch errors
    From: Andrés Ruiz
    Date: 2008 Jul 14, 09:21 +0200
    Current Bowditch errors


    From my mail [NavList 3693]:

    Bowditch use for the calculation of the meridional parts two concepts that are based in none model:

    a = 21600.0/(2.0*PI)  is used in the spherical model of The Earth

    f  = 1.0/298.26       is used in WGS72, but this use a = 6378135.0/1852.0

    Also there is some confusion in commercial Route planners use different kind of sailings:

    -       OziExplorer – Great circle and great ellipse
    -       C-MAP - PC Planner V 11.0.0 – Middle-Latitude Sailing , wrong for long routes
    -       MapTech OffShore Navigator – Mercator sailing or loxodromic, WGS84?


    De: NavList@fer3.com [mailto:NavList@fer3.com] En nombre de Anabasis75@aol.com
    Enviado el: viernes, 11 de julio de 2008 17:46
    Para: NavList@fer3.com
    Asunto: [NavList 5801] Re: Noon sight for longitude


    I am advised that the current Bowditch has many more errors. I quoted
    from the 1952 edition, where the limits are stated as, "for a stationary
    observer," and "if there has been no change in declination." I advise my
    students to use an older edition of Bowditch.

    Jim Wilson

    NavList 5800] Re: Noon sight for longitude




    Except for some information on the electronic navigation systems, modern editions of Bowditch, starting with the 1995 edition, have been generally inferior in most respects.  My favorite edition is 1985 Vol I, 1981 edition Volume II.  One small note, the more modern Meridional parts tables are slightly different and more accurate, but I don't think it matters all that much.



    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To unsubscribe, email NavList-unsubscribe@fer3.com

    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