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: mid-longitude sailing
    From: Bill B
    Date: 2007 Jan 10, 16:44 -0500

    Bill wrote
    > I did play with departure
    > and destination latitudes approaching zero and those seem to be a wee bit
    > off at first blush.
    My error.  "...latitudes approaching zero..."  should read "longitudes
    approaching zero."
    Lu wrote:
    > 2.  Any great circle course, when plotted on a Mercator chart, looks a
    > curve swinging towards the nearest pole and then back down again.  The
    > rate of change of a course is greatest in the higher latitudes.  If I
    > were trying to translate a great circle course into steering directions,
    > I'd want to calculate course direction more frequently near this
    > northward (or southward) peak than at lower latitudes.
    In George's defense, he did note that the one could subdivide a long
    passage.  He stated, "Having the coordinates of that middle-point, you can
    then easily split each half further, and so on, using the same method, until
    your point-to point legs are short enough to treat each one as a
    Given a programmable calculator or computer, or more time the other
    formula's are fine.  With nothing more than the simple formula George
    presented and a $10 pocket calculator one can do the job on the fly.
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to 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