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: Hezzanith Sextant
    From: David Pike
    Date: 2020 Sep 7, 07:29 -0700

    Al Stewart. You were asking about your Heath sextant.

    I agree with Bill Morris’ conclusion that your Heath sextant is pre 1969.  This is only the date on its most recent calibration certificate.  Heath was merged with WF Stanley & Co in 1937, and you can’t find much about WF Stanley & Co after 1960 (https://www.gracesguide.co.uk/W._F._Stanley_and_Co) .  A previous owner must have needed it overhauling or recalibrating in 1969.  Heath clearly wasn’t issuing certificates by then, and the National Physical Laboratory stopped calibrating sextants in 1947 (https://www.cambridge.org/core/journals/journal-of-navigation/article/div-classtitlethe-admiralty-compass-observatorydiv/A2858BB54D3A0E387B0EA4C04779E80E). The choice in the UK would have been to take the sextant to the Admiralty Compass Observatory, B Cooke & Son, Hull, or Kelvin Hughes.  Kelvin Hughes must have been chosen.  The Perspex over the certificate is typical of post WW2 Kelvin Hughes sextants, but I can’t imagine Hughes using what look like aluminium Phillip’s or ‘Posidrive’ screws. As late as 1961, they were using round headed, slotted brass screws to retain the Perspex.

    Regarding adjustments, you can’t be more than 10 miles from the sea.  Why not just try your sextant as is?  You don’t even need to do any calculations if you use Frank’s GPS Anti-Spoof App.  If you get satisfactory results for your requirements, forget further adjustment.  I’m always wary of making things worse, but that’s probably just me. DaveP

    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