Guest Posted January 22, 2012 Share Posted January 22, 2012 Bloody hell PaulR!! I was wanting a few pointers in the right direction!...... I wasn't expecting a dissertation! Thank you very much though. Very helpful! If your Plath isn't plastic and it's not brass can I assume it's aluminium? .......or are there other materials that sextants are made of too? I did see a white one and the description said it was metal.....would it have been powder coated or something? Link to post Share on other sites
PaulR 3 Posted January 23, 2012 Share Posted January 23, 2012 Weight savings can be made by having different casting patterns for the main frame. Mine is solid brass casting but with a square box lattice structure rather than round ring structure that other sextants favour. Further the screw arc gearing is in a lighter metal, possibly an aluminium, but firmly attached to the brass frame. So the same material but more structually engineered for weight saving, but at a much higher cost than the standard heavier ships' officers sextant. I also have NIL manufacturing errors over all sectors of the arc. It is the FRAME that keeps the mirrors and arm aligned, not the gearing / cogs that moves the index arm. The frame must be free of distortions. Aluminium expands / contracts too much, can flex as well. Mine is the traditional black, not sure how it was painted, but probably too old for powder coating. The only paint worn part is the plastic moulding that carries the light source to the arc scale. Yes white powder coating is an option, but covering what material No doubt today you could have any colour you like if ordered from the manufacturer and one is prepared for delivery delays etc, knot to mention price. At least then yours could be unique, in a day glow / fluro or poka dot pattern; but will it match your handbag and gloves Details. Nobody else seemed to answer your real questions - What do I need to look for What features are available etc. Hence my mention of the smaller/cheaper yachtsman types as well. But I am not an expert at all. Others know heaps more Link to post Share on other sites
PaulR 3 Posted January 23, 2012 Share Posted January 23, 2012 http://www.cassens-plath.de/katalog/index.html?startpage=90 A quick google brought this up. Page 90 is the start if the sextants and further on you can see the different telescopes, cases etc. available, and the "Astigmatizer" I mentioned. Happy reading. Link to post Share on other sites
Spirit of Wray 0 Posted January 24, 2012 Share Posted January 24, 2012 I currently own a FREIBERGER and an EBBCO. They represent both ends of cost and quality. Plastic sextants like the Ebbco or the more refined Davis are great for sun sights. If your are serious and want to do star sight then the Freiberger is ideal. Frieiberger is Alloy so a little more weight makes it a slightly more steady platform for star work , also has Zeiss optics! Trade me is a good venue for buying. All depends on your budget! Link to post Share on other sites
DrWatson 381 Posted January 26, 2012 Share Posted January 26, 2012 For those of you wanting an introductory book to celestial nav, and a look at the maths and geometry behind it, there is an enthusiastic amateur who has a website and has written a free book. I found this last night after looking around the web for other stuff, and read full half of it before deciding i should at lest grab an hours sleep before work... http://mysite.verizon.net/milkyway99/si ... Teacup.pdf The guy also has instructtions on how to build your own Octant out of wood. I kid you not. http://mysite.verizon.net/milkyway99/si ... octant.pdf Link to post Share on other sites
Guest Posted January 26, 2012 Share Posted January 26, 2012 Somewhere on the net there are instructions for building a sextant out of an old CD Link to post Share on other sites
Guest Posted January 29, 2012 Share Posted January 29, 2012 For those of you wanting an introductory book to celestial nav, and a look at the maths and geometry behind it, there is an enthusiastic amateur who has a website and has written a free book. I found this last night after looking around the web for other stuff, and read full half of it before deciding i should at lest grab an hours sleep before work... http://mysite.verizon.net/milkyway99/si ... Teacup.pdf The guy also has instructtions on how to build your own Octant out of wood. I kid you not. http://mysite.verizon.net/milkyway99/si ... octant.pdf Thanks heaps for your input everyone. This first link to the intro to celestial nav is fantastic!!! I can highly recommend it to all as very readable and very clear. Cheers DrWatson! Link to post Share on other sites
Guest Posted February 12, 2012 Share Posted February 12, 2012 What about this one guys? http://www.trademe.co.nz/motors/boats-m ... 437763.htm I've bid up to $500 which is the reserve, so I guess I own it if no one else bids......but what do you reckon? What would you pay up to? Link to post Share on other sites
Guest Posted February 12, 2012 Share Posted February 12, 2012 I'd expect that to hit $1k easily, they are sweet instruments. Link to post Share on other sites
Guest Posted February 12, 2012 Share Posted February 12, 2012 Cheers Squid. I thought it looked like a half decent one. Would any one have any reservations about buying this particular one? Link to post Share on other sites
Guest Posted February 12, 2012 Share Posted February 12, 2012 No one with any brains. Link to post Share on other sites
Megwyn 2 Posted February 13, 2012 Share Posted February 13, 2012 Good luck! Link to post Share on other sites
PaulR 3 Posted February 13, 2012 Share Posted February 13, 2012 It certainly looks good from the photos and description. The scratch on the outside of the box is nothing. Don't try and revarnish that. Your sextant will then look like you have used it for years. Hope you are successful I won't be bidding against you. Link to post Share on other sites
Guest Posted February 16, 2012 Share Posted February 16, 2012 WWWWWHHHHHHHHHAAAAAAAAAAHHHHHHOOOOOOOOOOOOO!!!!!!!!!!!!!! Scored this Tamaya Sextant off trade me for $500 Pretty happy about that as you can see!! Cheers to all crew.org members that helped me out with advice etc. Link to post Share on other sites
ab1974 1 Posted February 16, 2012 Share Posted February 16, 2012 Well done - reckon that was a good buy. Nice looking bit of kit. Now to get it to work! Link to post Share on other sites
Guest Posted February 16, 2012 Share Posted February 16, 2012 Good Buying! Link to post Share on other sites
Farrari 4 Posted February 16, 2012 Share Posted February 16, 2012 From what everyone has said, that looks like a good buy C29. I am curious what you are planning on using it for? Navigating by the stars sounds fascinating and something on my to do list. Is the use of a sextant only for international travel or does it have some value for coastal navigation? Excuse my ignorance if this is a stupid question. Link to post Share on other sites
Guest Posted February 16, 2012 Share Posted February 16, 2012 Coastal you can use it to calculate distance off something of a known height (like a lighthouse). Simple trig, if you know the length of one side of a triangle and two of the angles (one is a right angle) you can calculate the length of the other side (your distance from teh lighthouse. But most just use a set of tables or a calculator. Take a bearing at the same time and you have a fix. Link to post Share on other sites
SloopJohnB 322 Posted February 16, 2012 Share Posted February 16, 2012 What about horizontal angles? Link to post Share on other sites
Megwyn 2 Posted February 16, 2012 Share Posted February 16, 2012 Congrats C29 - its great when it all comes together! Link to post Share on other sites
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