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: My first Lunar
    From: George Huxtable
    Date: 2008 Sep 22, 23:16 +0100

    Paul Hirose wrote
    | George Huxtable wrote:
    | > The Moon's angular speed
    | > through the stars changes; the lunar distance target body may misalign 
    | > the direction of the Moon's motion; and particularly, "parallactic
    | > retardation" may play a big part.
    | According to my program, the topocentric lunar distance was increasing
    | 22.2" per minute of time, and the geocentric distance increasing 35.1"
    | per minute. These rates are 93% and 97% (respectively) of the total
    | angular velocities of the bodies.
    Thank you, Paul; that's useful information.
    Paul is saying that the topocentric lunar distance, the actual angle 
    measured from the Earth's surface, is changing by 22.2" per minute of time. 
    This is indeed  significantly less than the Moon's "nominal" speed of 30" 
    per minute, but is over two-thirds of it. In which case, I remain rather 
    puzzled that Frank's lunar calculator comes up with a calculated error of 
    only 26' or 27', less than half of the contrived error in longitude of 1º. 
    Am I misunderstanding something? Can anyone explain? Perhaps it calls for an 
    understanding of the inner workings of Frank's calculator.
    contact George Huxtable, now at george@hux.me.uk
    (switched from george@huxtable.u-net.com)
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. 
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To unsubscribe, email NavList-unsubscribe@fer3.com

    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)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site