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: almanac SHA
    From: Paul Hirose
    Date: 2013 Apr 21, 11:15 -0700

    Herbert Prinz wrote:
    > The analysis is based on a critical table of SHA values generated with MICA 
    2.0. The current version is apparently 2.2.2. I could not find out from the 
    USNO website what the updates are and whether they are crucial to the 
    validity of my test.
    I have the same MICA version. By trial and error I've determined its
    precession / nutation model is IAU 1976 / 80 with no frame bias
    correction. The result is different enough from the current IAU 2006 /
    00A model that my Tinyac program has a feature to generate coordinates
    compatible with MICA.
    According to the USNO site, the "2000K" nutation model (not an IAU
    model) replaced the IAU 2000B model in MICA, so the version you and I
    have is at least two nutation revisions out of date. But in this case
    the vital point is not which model is more modern, but which one matches
    the software that computed the Nautical Almanac. I have no idea.
    I filter out messages with attachments or HTML.

    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