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
    or...
       
    Reply
    Re: Poor St. Hilaire
    From: John Karl
    Date: 2007 Oct 27, 18:56 -0700

    
    I sure can understand why some of you are wondering what all the St.
    Hilaire fuss is about.  I'm new to the List and 'am finding out how
    hard it is to carry on technical discussions in this format - as some
    of you have mentioned.  A major, major, part of the problem is
    definitions, and understanding what each other means - as others of
    you  have said.  After starting this topic, now with 36 posts under
    two topic headings (are topic headings "threads"?), I still haven't
    got my point across.  I'm embarrassed, and apologize for not being
    able to communicate better.
    
    I was speaking from the viewpoint of a modern author introducing the
    St. Hilaire method and the reader trying to understand.  I'm talking
    about how the method is introduced in any number of commonly used
    books: books by Blewitt, Bowditch (2000 edition), Cunliffe, Dutton
    (2004 edition), Howell, Letcher, Meyrier, Moody, Schlereth, Turner,
    and Toghill, to name a few.  These authors all are discussing using HO
    229, HO 249, or a calculator.  They are all talking about finding a
    single LOP - not a fix, not an iteration of fixes.  They're not taking
    about older log-trig methods or the Sumner method.
    
    My statement was that all of these authors either don't attempt to
    explain the REASON for the assumed position, or they explain it
    incorrectly.  For example,
    
    A. Some say that an assumption is necessary because the distance
    between the sun's GP and the ship is too great to plot.  While that's
    true (for most sights and charts), it's not the reason for the assumed
    position.
    
    B.  Some say the AP is necessary because there's insufficient
    information to plot the LOP.  That's false.  We know everything
    necessary to plot the LOP
    
    C.  Others say the AP is necessary because we don't know how to plot
    the exact LOP.  That's also false.  They are several ways to plot the
    LOP exactly.
    
    I mused about WHY so many authors either don't explain the reason for
    the AP, or they have it incorrect - I think that the term "assumed
    position" has misled these folks.  But of course, that's only my
    guess.
    
    I wonder what List members think the reason is for their
    misunderstanding, particularly when they're supposed to be teaching
    others!  No one has addressed this - yet.
    
    John
    
    
    --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

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

    Email Settings

    Posting 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