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
    Nomograms and emergency navigation
    From: James R. Van Zandt
    Date: 2007 Oct 15, 07:54 -0400

    I've always had my doubts about the actual practicality of a lifeboat
    sextant (i.e. that they were intended mostly to impress the
    passengers) - since CN would also require a cronometer, an almanac,
    and a calculator or sight reduction tables.  If the ship's officers
    were bringing those to the lifeboat, then why not bring a good sextant
    However, with the sextant alone one could still determine latitude.
    A few weeks ago, Andrew Nikitin posted some nomograms for altitude
    correction, with the suggestion they could be attached to the sextant
    itself.  I suggest one additional nomogram, for reduction of a Polaris
    sighting.  I envision a star chart of the polar region, surrounded by
    a circular scale, with instructions something like this:
      "Rotate the figure to match the sky, then read the correction from
      the scale directly under Polaris."
    I also suggest the offset of Polaris from the north pole in the chart
    be exaggerated, so the navigator can confirm the sign of the correction
    for himself.  I would also include a worked example.
                    - Jim Van Zandt
    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