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
    Re: Star Sha & Dec changes.
    From: Brad Morris
    Date: 2013 Jan 31, 13:47 -0500

    Chief Franklin

    If you will examine the 1849 issue of Bowditch, you will find Table VIII, which is the right ascensions and declinations of some of the fixed stars along with the annual variation, starting from the beginning of the year 1830.  Its not 1500, but its roughly 200 years closer than today!


    Of course, SHA=360-RA, so you get the terms you are looking for.

    You can use this data to extrapolate backwards & forwards in time.  I suggest that you first extrapolate forwards to today, to see what precision you obtain.  Once you understand how it projects forward, you can then extrapolate backwards.

    This will not be a highly accurate method, but considering that the intended use is plotting on the base of the 2102D, it may very well suit your purposes. 

    Brad Morris

    On Jan 31, 2013 11:37 AM, "Byron Franklin" <byronink---.com> wrote:

    I am working on a project and need information on SHA & dec changes
    for stars. I want to replot some star on my 2 minute star finder to recheck
    sighting postions on the old mill in Newport RI. Mill may have been built
    year 1500. How much star changes? The noticed change SHA & Dec is interesting.
    Any old date year will give clue if not 1500.
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com

    View and reply to this message: http://fer3.com/arc/m2.aspx?i=122198

    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