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
    Name or NavList Code:
    Re: Latitude from date and length of daylight?
    From: Frank Reed CT
    Date: 2005 Feb 13, 21:25 EST
    Jared wrote:
    "It seemed interesting, that with just a watch and calendar
    one should be able to get latitude this way. Since most modern watches run
    to better than a second a day, this would seem to be a reasonable navigation
    You can get longitude, too. If your watch is running well, as you travel east, sunrises and sunsets will occur at earlier and earlier watch times.
    This technique of navigation is actively employed on a small device that operates in an area inaccessible to GPS signals --underwater. Do you have $4200 to spare? Then you, too, can be the proud honor of a celestial navigating fish tag. I brought this up briefly on the list over a year ago. Here's a link to their web site and a description of the device: http://microwavetelemetry.com/Fish_PTTs/archival.php
    They get one-degree-ish estimated accuracy in latitude and longitude by timing sunrise and sunset (based on light levels corrected for depth, which is measured by pressure). This may be one of the last scientifically significant uses of celestial navigation. I guess it was easier than teaching the tuna to use sextants and H.O.229.
    "Has anyone seen a formula for this, or does anyone want to give it a try?"
    The easiest way to do it would be trial and error with the standard formulas for sunrise/sunset. Or with an almanac, just interpolate.
    42.0N 87.7W, or 41.4N 72.1W.
    Browse Files

    Drop Files


    What is NavList?

    Get a NavList ID Code

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.

    Email Settings

    NavList ID 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