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: Extremely poor conditions??
    From: David Fleming
    Date: 2012 Mar 21, 09:17 -0700

    My conclusion about terrestial refraction equaling refraction of the Suns LL is not justified. (It ignores further solar refraction that occurs beyond the horizon as the rays enter the atmosphere.)

    Still the terrestial refraction of the horizon causes the horizon to appear higher than geometry would imply, ie the visible horizon is beyond the geometric horizon and rays are bent to follow somewhat the earths curvature.

    With an enhanced air desity gradient due to cooling effects of the water this curvature is increased, the horizon is further lifted and the altitudes are less than expected.

    Dave Fleming
    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