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: Celestial Navigation without a sextant.
    From: Greg Rudzinski
    Date: 2008 Mar 9, 16:49 -0700

          In a lifeboat with a chronometer,tables, and compass (no
    sextant), a navigator would be able to mark the GMT time of the sun's
    limb on the horizon. The elevation is zero. Correct for refraction,
    semi-diameter, and height of eye (dip). Perform normal sight reduction
    and expect 6 minutes of arc accuracy under normal weather conditions.
    Morning and evening LOP's may provide a running fix opportunity. Final
    landfall would be made by sailing along an LOP to the destination. If
    clouds threaten to obscure the sun at the horizon then estimate
    elevation above the horizon by counting solar diameters to the lower
    limb. One solar diameter at the horizon will be about 33 or 34 minutes
    of arc. A finger width held at arms length equals about 2 degrees of
    arc. Expect 20 minutes of arc accuracy up to 4 degrees of elevation.
    The lifeboat compass can be checked for deviation at the same time.
         If given a choice , I would trade the chronometer for a sextant
    and then latitude sail using Polaris, LAN, or a star's meridional
    passage.
    
    On Mar 7, 11:41 am, 40 South  wrote:
    > Supposing one was in a small boat with an accurate timepiece and the
    > necessary tables, how accurate could you determine your longitude by
    > observing the rising or setting of the sun or any other celestial
    > body?  Also, assuming you had a compass and were north or south of the
    > tropics, would it be possible to estimate your latitude by taking a
    > bearing of the setting or rising of a celestial body?
    --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    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