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: Star - Star Observations
    From: Andrés Ruiz
    Date: 2010 Mar 10, 16:49 +0100

    I think the nomenclature is something confused in this issue! Only for clarify:

    The method is the same as in Lunars doing SD = 0 and Parallax = 0

     

    Sextant altitudes: Hs1, Hs2

    Apparent altitudes: m, s

    Observed or true:  M, S

    Star 1:

    m = Hs1 - Dip

    M = Hs1 - Dip - R1

    Star 2:

    s = Hs2 - Dip

    S = Hs2 - Dip - R2,

    Apparent distance:

    d -> sextant

     

    Correction for refraction:

    Do = YoungFormula( double m, double M, double s, double S, double d )

    {

          double a1 = COS( d );

          double a2 = COS( m+s );

          double a3 = (COS(M)*COS(S))/(COS(m)*COS(s));

          double a4 = COS( M+S );

                     

          return( ACOS( (a1+a2)*a3-a4 ) );

    }

     

    Calculated star-star distance:

    cos D = sin dec1 sin dec2 + cos dec1 cos dec2 cos (SHA1-SHA2)

    cos D = sin dec1 sin dec2 + cos dec1 cos dec2 cos (GHA1-GHA2)

     

     

    Error = IE + arcError = D – Do

     

    regards,

    ---

    Andrés Ruiz

    Navigational Algorithms

    https://sites.google.com/site/navigationalalgorithms/

     

       
    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