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: H. Hughes and son sextant pat 491
    From: Brad Morris
    Date: 2019 Dec 2, 18:15 -0500
    Hi David

    Cmdr Bauer's star to star distances are uncorrected for refraction.  Consequently, they are of little value for the purpose be describes.  On the other hand, his description of sextant servicing is fairly good in my opinion.  Your milage may vary of course.

    Sam:  

    Servicing your own sextant is fairly straightforward and, as a practical matter, makes you acquainted with your sextant.  It is worthy endeavor to try by yourself!

    Brad




    On Mon, Dec 2, 2019, 4:18 PM David Pike <NoReply_DavidPike@fer3.com> wrote:

    Sam Loveday you wrote:  I have acquired the wonderful instrument and wish to have it serviced. Does anyone know of any services in Australia that might be able to help me?

    Good day Sam
    Congratulations upon becoming a sextant owner.  If you’ve not yet tried using it, I would be tempted to do so before worrying too much about having it serviced.  If your Hughes sextant still has its crinkle finish paint on, then there’s a good chance it’ll still be in good condition.  The main reason for RN and RAAN sextants going into store is because of reducing numbers of ships and personnel, or because someone decided modern sailors needed more modern sextants, so the chances are that they went into store perfectly serviceable.  Unless, your sextant has been badly treated since disposal by the government, then it’s probably still OK.  If on the other hand your sextant came to you as shiny as a new pin, as at least one firm in the UK is advertising them ( https://www.trinitymarine.co.uk/shop/royal-navy-silver-scale-sextant-henry-hughes-son-polished/ ), then appearance might have been allowed to take precedence over accuracy, and it might need closer attention, because you can’t get all the paint off and polish the brass without disassembling it and reassembling it again.


    You can do the three main checks of perpendicularity, side error, and index error yourself.  I’m sure you’ll find them online, but if not, the instruction is particularly well done with photos of what you can expect to see through the eyepiece using the very similar Hughes Mate’s sextant in Tom Cunliffe’s ‘Celestial Navigation’.  Otherwise, it’s hard to understand what the articles on about.  In ‘The Sextant Handbook’,  Cmdr Bruce Bauer puts forward a very interesting method for checking the overall accuracy of sextants, which I’ve never tried, using the angular distance between pairs of major stars, and he provides a table to do this although these values do change very slightly with time.  For none of these checks do you need to be near the sea.  Hope this helps. DaveP

    View and reply to this message

       
    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