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: Azimuth and Declination formulae
    From: Fred Hebard
    Date: 2005 Jul 14, 22:35 -0400

    On Jul 14, 2005, at 8:29 PM, Peter Fogg wrote:
    > Along the way, I found a formula for the calculation of the Sun's
    > declination:
    > Dec = 23.45 sin (360/365.25)
    > Its such a simple formula even I can understand it. Its the maximum
    > declination of the sun expressed as a proportion of its change.
    > Here's another version:
    > Dec/23.45 = sin(0.985*t)
    > 0.985 is a truncated version of (360/365.25)
    > and t = the number of days from the vernal equinox
    > or
    > t = (inv sin(Dec/23.45))/(360/365.25)
    > These formulae come from:
    > www.geomancy/org./sunfinder
    It's more accurate to use the length of the season as one quarter of a
    circle, but even then there are errors.  The reason for this is that
    summer is longer than winter, about 93 days versus 87.

    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