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: Beware of Noon Sights this time of Year
    From: Don Seltzer
    Date: 2018 Mar 31, 10:22 -0400
    Initially it seems puzzling as to how they could misread their compass so badly and stray so far north from their intended easterly course.  Perhaps they were carried NE by the Gulf Stream for a considerable distance while pointing the ship's bow East.

    It is also possible that they did not adequately understand magnetic declination.  For 1815, declination would have been near zero when they left port but rapidly increasing westward as they crossed the Atlantic.  By the time they reached the latitude of the British Isles, magnetic declination was about 30° west. 

    Don Seltzer

    On Sat, Mar 31, 2018 at 10:01 AM, Robin Stuart <NoReply_Stuart@fer3.com> wrote:

    The dates and locations are quite specific. The error in latitude will be twice the Sun’s declination. For the Orkney’s the latitude difference is 23° and the Sun’s declination on the 19 April, 1815 was around 11°N. For Christian Sound (Kritiansund) the latitude difference is 27° and the Sun’s declination 13.5°N. It would be no easy task to construct a fanciful tale in which the differences in latitude, changes in declination and traverse times all line up so well,

    Robin Stuart

    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