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: Pear shaped Earth
    From: Dave Weilacher
    Date: 2002 Oct 2, 05:11 -0700

    My conclusion from this is that a pear shaped earth has a negligible effect on
    the accuracy of sight reduction.  It doesn't matter what distance you are from
    the center of the earth (well there is an over-simplification) as long as the
    horizon is also at the same level.  Since the horizon is likely to be only 4
    to 10 nm away, this pear shape notion becomes moot because you and the horizon
    are at the same height.
    On Wed, 2 Oct 2002 16:28:29 +1000 Peter Fogg  wrote:
    > David Weilacher wrote:
    > > Can anyone give me a numerical representation
    > of the shape of earth?  I'm
    > > thinking something like the length of a line
    > of latitude for each 10 degrees
    > > north and south of the equator.
    > I'm told that Meridional Distances do indicate
    > this:
    > 10 d lat  597.11
    > 20        1194.58
    > 30        1792.72
    > 40        2391.75
    > 50        2991.82
    > 60        3592.91
    > 70        4194.91
    > 80        4797.59
    > 90        5400.63
    > so, if I've understood correctly, a degree at
    > 10d of lat.is 59.71 nm, and a
    > degree at 90d of lat. is 60.007 nm.
    Dave Weilacher
    .US Coast Guard licensed captain
    .    #889968
    .ASA certified sailing and celestial
    .    navigation instructor #990800
    .IBM AS400 RPG contract programmer

    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