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
    Name or NavList Code:
    Email:
       
    Reply
    Seasonal variations in delta-T
    From: Frank Reed
    Date: 2010 Mar 2, 21:12 -0800

    Years ago, Richard Langley posted some nice little graphics showing variations in the Earth's rate of rotation from about 1960 to 2000. Have a look here:
    http://www.fer3.com/arc/m2.aspx?i=016750

    You can plainly see the seasonal cycles, and you'll notice they are quite large compared to the long-term variations. The third graphic is probably most relevant here. It shows changes in the length of day in milliseconds. There's another one showing picorads per second, if that's your cup 'o tea.

    -FER

    ----------------------------------------------------------------
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com
    ----------------------------------------------------------------

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

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

    Email Settings

    NavList ID 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