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: 6080 ft vs 1852 m
    From: Gary LaPook
    Date: 2007 Oct 22, 23:01 -0700

    Gary LaPook writes:
    
    You got that a bit wrong, the meter was originally defined as one ten 
    millionth of the distance from the equator to the north pole. The 
    nautical mile is the length of one minute of latitude, 5400 between the 
    equator and the pole. Since the size and shape of the earth varies none 
    of these are accurate at all places on the earth so the choice of the 
    length to use for the nautical mile is somewhat arbitrary. It used to be 
    defined as 6080 feet but by international agreement it was redefined to 
    be exactly 1852 meters, hence 6076.1155 feet, close enough for 
    government work.
    
    
    BTW, going back to first principles, ten million meters divided by 5400 
    nautical miles equals 1851.851851851851851851851..... awfully close to 
    1852 meters per nautical mile, accurate to 8 one thousandths of one 
    percent, .008%
    
    
    Dan Allen wrote:
    
    >Occasionally you will see a reference to an "Admiralty mile".  In the  
    >1800s this was used by England and was 6,080 feet long.
    >
    >Today England uses a new "nautical mile" and it is a bit shorter at  
    >1852 meters exactly, or 6,076.1155 feet long.
    >
    >Q1:  Does anyone still use the older, slightly large British nautical  
    >mile?  Do any parts of England still refer to it?
    >
    >Q2:  Why was the change made?  Was it part of the move to metric in  
    >the 1970s?
    >
    >I know that the distance of a nautical mile was originally to be  
    >1/10,000,000th of the distance from the equator to the poles but  
    >early estimates of this distance were out a bit.  Was this an  
    >influence on the adoption of a "new" nautical mile?
    >
    >Dan Allen
    >N39.997� W111.757�
    >
    >
    >
    >
    >
    >>
    >
    >  
    >
    
    
    --~--~---------~--~----~------------~-------~--~----~
    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