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
    Name or NavList Code:
    Email:
       
    Reply
    Re: Celestial Navigation without a sextant.
    From: Peter Fogg
    Date: 2008 Mar 9, 14:38 +1100

    George wrote:
    
    >  So timing sunrise/sunset will
    >  never provide a precise value for longitude. But if a rough ball-park figure
    >  will suffice, it could do the job.
    
    Here's a thought: if the time of apparent sunrise/sunset was observed regularly;
    the extent of the difference or inaccuracy shown by observation
    compared to calculated data could be evaluated on a regular basis and
    contrasted with other information about position.
    
    Given that the effects of anomalous refraction can constitute a
    significant constraint upon the accuracy of observations taken from
    the deck of a small boat, thus from within the lowest band of
    atmosphere, and that there is no way of knowing whether they are
    present, let alone the extent of inaccuracy introduced;
    
    If this known difference between observed and calculated
    sunrise/sunset should change, could it be a indication of the extent
    of anomalous refraction likely to affect sights taken close to that
    time, eg; star sights just before dawn, or just after sunset?
    Particularly sights taken in that direction?
    
    --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To , send email to NavList-@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.
    Email:

    Email Settings

    NavList ID 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