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
    Name or NavList Code:
    Re: sextants on aeroplanes
    From: Guus Dekker
    Date: 2008 Nov 19, 03:24 -0800

    Hi Jack,
    In TM-1-206 Technical Manual Celestial Air Navigation, March 4, 1941
    chapter 56 page 114 sub. d "Limitations of marine type" says:
    "The marine type sextant is not suitable for aircraft use except on
    those rare occasions when the airplane is flying over the sea at a
    very low altitude (less than 1,000 feet). Since the instrument employs
    the sea horizon as a reference line, it is of no practical value when
    the aircraft is flying over land, over clouds or haze, or at high
    altitudes when sky and sea tend to blend into each other and do not
    form a clear-cut horizon  line. Even when the sea is clearly visible
    from relatively high altitudes, the altimeter does not indicate height
    of the airplane with sufficient reliability to determine height of eye
    (dip) correction accurately. Furthermore, the marine type sextant
    cannot be used at night when the natural horizon is not visible. Some
    types of marine sextants are equipped with a bubble leveling
    attachment and light, thus enabling a heavenly body to be observed day
    or night regardless of whether the natural horizon is visible."
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To , email NavList-@fer3.com

    Browse Files

    Drop Files


    What is NavList?

    Get a NavList ID Code

    (please, no nicknames or handles)
    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 Settings

    NavList ID 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