Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: A, B & C Azimuth Tables Questions
    From: Greg Rudzinski
    Date: 2017 Feb 20, 06:59 -0800

    Doug,

    The 1938 part 2 copy of Useful Tables from the American Practical Navigator has no dedicated tables or forms designed to calculate azimuth other than table 39 Amplitudes. If mariners wanted to calculate azimuth then table 44 (log sines, tangents, and secants)  or 10" slide rule would have to be used.

    Here is what a tabular azimuth solution would look like using table 44 log secants.

    Given:

    Lat. 27° 41' N  

    Dec.10° 58' S

    LHA(t) 57° 53'

    Hc 21° 57'

    Formula: Sin Z  =  CosDec  Sint  /  CosHc

    Log SEC Dec}   .00800

    Log CSC t      } +.07213

              Sum           .08013

    Log SEC Hc  } -  .03268

              Sum           .04745  Inv Log CSC

                       Z  =    63° 42'

    180° + 63.7°   =   243.7°  Azimuth

    Greg Rudzinski

    From: Doug MacPherson
    Date: 2017 Feb 19, 13:10 -0800

    I find the A, B, and C Azimuth Tables a great addition to my CN tool kit. I use the versions found in Norie's Nautical Tables.

    Does anyone know when these were first published in Norie's? Were they in the original edition back in the 19th century? I have never seen them in any editions of Bowditch. Was there a reason for this? Were they ever included in Bowditch?

    Thanks

    Doug

    38-34N 121-38W

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    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