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: Timekeeping in the post-WWV/post-HF world
    From: Roger W. Sinnott
    Date: 2018 Sep 26, 20:39 +0000

    Another graph in the article fits a straight line across all the data and exaggerates the ups and downs.  But they don't clearly indicate a seasonal variation.  The changes occur more leisurely, and I think they are related to aging of the crystal or the battery (or both). 

    The fairly steady gaining rate of 50.4 seconds per year is what I found remarkable.  Deviations of up 7 seconds either way were measured with respect to this rate.  If a navigator determined the rate from a shorter interval (say, 1 year instead of 4), and extrapolated for a similarly short interval beyond that (1 year again), the deviations would be much less than 7 seconds.

    In the article, I analyzed the time-keeping quality of this watch by the same method that was used 250 years ago to judge Harrison's No. 4 chronometer (as described by Rupert T. Gould in his classic, The Marine Chronometer) .  My $6 watch did considerably better than that chronometer.

    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)