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: Doing my homework
    From: John D. Howard
    Date: 2016 Nov 3, 16:52 -0700


    Thanks for your reply but I think I must clear up something you said.  The form you are using is correct.  When you add GHA to a WEST Longitude you are adding a negative number ie you are subtracting.

    LHA + EsLon                  3 d + (-) 66 d 30 m = 3 d - 66 30m = -63 d 30 m.

    LHA is always between 0 d and 360 d so you must "normalize" the negative LHA by adding 360 to it.  ( If LHA was 425 d you would subtract 360 )

    LHA = -63 d 30 m + 360  = 296 d 30 m            LHA is Greater than 180 so the second rule would be used ie   t = 360 - LHA    

    t = 360 - 296 d 30 m = 63 d 30 m

    Rember LHA does not have a sign and is always 0 to 360.  You must normalize if outside that range.  t has a sign: negative for west or postive for east.

    John H.

    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