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
    Sextant accuracy with short distance to horizon
    From: Richard B. Emerson
    Date: 2001 Jun 21, 8:47 AM

    Dan Allen writes:
    [...]
     > This led me to think more about possible inaccuracies of using a horizon
     > that is very close rather than naturally far away.  That is, typically you
     > use a horizon that is at the limit of your vision, perhaps 20 miles away.
    [...]
    
    While you're in Bowditch, check out table 12, "Distance of the
    Horizon".  Assuming you're 6' tall and standing on a deck 4' off the
    water, for a total height of eye of 10', the horizon is 3.7 miles
    off.  A twenty mile horizon requires a height of eye of something like
    300'.  And clear air.  [grin]
    
    Rick
    S/v One With The Wind, Baba 35
    

       
    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