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
    Re: Real accuracy of the method of lunar distances
    From: Jared Sherman
    Date: 2004 Jan 15, 21:08 -0500

    George-
     [js]".05 seconds of arc [or] 0.2 >seconds of time."
    [gh]I have no idea, none at all, what those numbers are supposed to represent
    
    In your reply to me, you said that an error or .05 seconds of arc, which is 
    equivalent to a change of 0.2 seconds in the GMT figure resulting from 
    clearing a lunar, could be ascribed to the effect of "parallatic 
    retardation".
    
    I asked you what the gross error in local time ( or position relative to 
    Greenwich, whatever one prefers to call it) calculation might be due to 
    parallatic retardation. Your answer that this effect might cause a difference 
    of 0.2 seconds, when a skilled observer can only ascertain their position 
    within 60 seconds, is what your answer meant to me.
    
    Or did I completely misunderstand you? My question was and is, how great an 
    effect this tempest in a teapot has on the final result produced by clearing 
    a lunar. Does it or does it not cause a maximum change of 0.2 seconds in the 
    final calculation of GMT, which a skilled observer can only hope to calculate 
    within one minute (60 seconds) at the best of times?
    
    
    

       
    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