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: Smart and Shearme Position Line Tables
    From: David Pike
    Date: 2020 May 5, 13:50 -0700

    As DaveP said, there are two possible solutions .....

    I was puzzling upon why I had to be careful where I stuck the string on the globe to come up with something believable when I realised that I wasn’t being bold enough.  How about this? To explain it without maths. Think of two wire rings lying on the surface of a globe, one a small circle of equal zenith distance (an ‘isozend’) and the other a meridian and its opposite.  If the two rings cross in one place, they must cross again somewhere else, even if it’s on the far side of the Earth and below the observer’s visual horizon.  DaveP 

    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