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: Celestial Navigation without a sextant.
    From: Gary LaPook
    Date: 2008 Mar 12, 03:19 -0700

    Gary LaPook writes:
    Your discussion reminded me that I used to use this technique from time
    to time for practice. I just looked in my wallet and found the little
    table I had prepared for this and which has been tucked under my pilot's
    license for more than thirty years. I have attached a scan of it . This
    table combines dip and refraction for all bodies (first column) plus
    semi diameter for the sun (lower and upper limb, second and third
    columns) when the body is on the horizon as observed from various flight
    altitudes and so gives the Ho of the observation. (all Ho's are
    negative.) I remember that I was impressed by the accuracy of using this
    table in flight ( compared to the usual level of accuracy of in flight
    cel nav, not to the standard of marine navigation) but I don't have any
    numbers to give you since it has been a long time since I used this table.
    frankreed@HistoricalAtlas.net wrote:
    >Jim writes:
    >"In his chapter "Celestial Navigation Without a Sextant" he has a worked
    >example using the sun as it sets which he claims "the LOP produced agreed
    >exactly with the distance run since a fix made earlier by advancing sun
    >Sometimes ya get lucky! It might be fun to try this ten days in a row and
    >see how well it works on average.
    >"I haven't tried this type of sight myself but was always a little curious
    >to try it."
    >Supposedly, Nathaniel Bowditch himself experimented with these sextant-free
    >sights on his first ocean voyage in 1795 but abandoned them. In his case,
    >though, I think he was trying to observe the rising and setting of stars.
    >Since he had never been to sea before, he apparently did not know that this
    >was basically impossible. And since they had no chronometer, the value of
    >these sights was minimal anyway.
    > -FER
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@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