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
    Name or NavList Code:
    Re: NavPac
    From: Jim Thompson
    Date: 2005 Jan 7, 17:15 -0400

    I guessed wrong as I was reading along, because I thought the pamphlet would
    have told George that it was Apparent time.
    Does not GHA Sun in the printed Nautical Alamanac that we use in North
    America relate directly to position of the apparent sun, rather than  the
    mean sun, hence we need to use the EqT to convert from GHA sun to get the
    position of the mean sun, for example?  I thought that all the GHA values
    for the various bodies in the Almanac related to apparent time, not mean
    Jim Thompson
    Outgoing email scanned by Norton Antivirus
    > -----Original Message-----
    > From: George Huxtable
    > I wanted to calculate GHA Aries rather
    > precisely. I knew that it corresponded to Greenwich Sidereal Time, but was
    > that Greenwich Mean Sidereal Time, or Greenwich Apparent Sidereal Time
    > (there's a small difference)? None of my texts on spherical astronomy
    > helped, and (though I thought I knew which) I didn't want to guess. But on
    > page 59 of the booklet I found - "Table 5 may be used to calculate GHA
    > Aries which is equivalent to Greenwich mean sidereal time (GMST)." Just
    > what I needed to know.

    Browse Files

    Drop Files


    What is NavList?

    Get a NavList ID Code

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.

    Email Settings

    NavList ID 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