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
    Oblateness correction
    From: Lars Bergman
    Date: 2010 Nov 30, 09:42 -0800

    In the Sight Reduction Procedure chapter in the Nautical Almanac, the correction for the oblateness of the earth, to be added to the Moon's parallax in altitude, is given (in degrees) as

    OB = -0.0032 (sin Lat)^2 cos H + 0.0032 sin (2 Lat) cos Z sin H

    where H is apparent altitude, Z true azimuth in the range 0 ... 360 and Lat is latitude in the range -90 ... 90. Now, in the second term the sine of two times latitude gets different signs depending on hemisphere. Shall it be like this, or ...?

    Lars, 59N 18E
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com

    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