A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2019 Dec 2, 04:53 -0800
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