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: Gnomonic charts and distances
    From: Robin Stuart
    Date: 2018 Jan 23, 06:42 -0800

    Bob,

    Commercial Gnomonic charts provide 2 graphical methods of determining great circle distances. At the bottom of this chart you can see Charles Lindbergh’s original construction doing just that. They also provide a nomogram (Lindbergh’s lines visible on chart) and table for determining initial great circle courses. How the nomogram works was discussed in the thread starting here and explained in detail here.

    Robin Stuart

     

    Note:

    My previous post contained a typo in the second equation and should have read

    Starting at a latitude, longitude L0, λ0 and traveling a distance D(°) on a course C° measured East from North the necessary formulas are:

    sin L = sin L0  cos D + cos L0 sin D cos C

    sin ( λ - λ0 ) = sin D sin C / cos L

       
    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