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
    Bisectors and MPP
    From: Doug Royer
    Date: 2003 May 29, 10:36 -0700

    I post this only as an alternative method to what was discussed the last few
    days.I have no idea which method would be more accurate to determine the MPP
    or any systematic error.This is the method I was taught to find the MPP from
    a round of sights.
    Use bisectors to establish the MPP of a round of sights when each body's Zn
    is seperated by more or less than 120* for a 3 sight round and 90* for a 4
    sight round.It is imperative to use bisectors if all Zn's in the round of
    sights are seperated by 180* or less.
    Each angle formed by a pair of LOP's is bisected at the vortex of the 2
    LOP's.Each bisector is drawn in the direction of the averaged direction of
    the 2 Zn's of the pair.Extend each bisector an equal distance on both sides
    of the vortex of the corresponding pair of LOP's.The point or area the
    bisectors intersect or nearly intersect is the MPP.
    Bn = (Znx + Zny)/ 2
    Star 1 Zn = 224*
    Star 2 Zn = 352*
    Star 3 Zn = 256*
    Bisector 1 = star 1 Zn + star 2 Zn = (224* + 352*)/ 2 = 288*
    Bisector 2 = star 1 Zn + star 3 Zn = (224* + 256*)/ 2 = 240*
    Bisector 3 = star 2 Zn + star 3 Zn = (352* + 256*)/ 2 = 304*
    From the point where each pair of LOP's intersect draw a line through that
    point useing the direction obtained with the bisector equation.
    Where the averaged Zn's intersect is the MPP.

    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