Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Northern Limits of Magnetic Compass Usefulness
    From: Tony Oz
    Date: 2019 Feb 6, 01:17 -0800

    Dear Bob,

    I experimented with a (supposedly "viking-style") Sun-compass which is much easier to build.

    When the weather|environment permits - it workds just fine, as accurate as a good magnetic compass (accounting for the current value of magnetic declination). I checked it on a sea shore by comparing the N-S line orientation with the actual direction to the Polaris in the evening.

    All you need is the gnuplot package, a bit of level cardboard and a dressmaker's pin (with a spherical top, that's important as a "shadow sharpener" feature).

    Placing the printed scale horizontally and sticking-in the pin vertically according to the pre-computed pin length|height you must rotate the assembly untill the center of the shadow is exactly on the line. At that moment the N-S line is properly aligned with the N-S geographic direction. And as a by-product you will know the Local Apparent Time. No external source of time is necessary! :)

    The PLT file (for my last year experiment) is attached, you will need to update the GHA|Dec table accordingly.

    Warm regards,

    Tony

    60°N 30°E

    File:
    Sun_Compass.zip
       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    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