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: Angular Distance Between Stars By Camera and Sextant
    From: Brad Morris
    Date: 2012 Sep 18, 13:48 -0400

    If I am measuring star-to-star distances, then I fail to understand how dip of the horizon is important

    Shouldn't the calculated altitude of the two objects be sufficient to determine the refraction? 

    Dip would be part of reducing the measured altitude, no?

    Best Regards
    Brad

    On Sep 18, 2012 1:04 PM, "Marcel Tschudin" <marcel.e.tschudin@gmail.com> wrote:
    Andrés, you clarified

    On Tue, Sep 18, 2012 at 7:08 PM, Andres Ruiz <navigationalalgorithms@gmail.com> wrote:

    Hc = Hc( B, L, Dec, GHA )
    Z  = Z( B, Dec, Hc, LHA( L, GHA ) );
    iterate to find Hs ( Hc = Ho = Hs + IE - dip - R )
    Ha = Hs + IE - dip;
    R = Refraccion( Ha, T, P );

    Ok, yes, I completely forgot that your program is for verifying sextant observations and does therefore more than just calculating the difference in star coordinates. However, since both star positions contain the same dip this should have no influence on the calculated star distance. The difference of 0.4 moa still waits to be understood.

    Marcel
       
    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