Hi Antoine , I appreciate your explanation of the sextant. I appreciate the skills of true navigators but I am thinking the sextant has gone the way of Morse code that I learned as a boy in Cub Scouts. Our Coast Guard no longer monitors Morse Code and doesn't teach it. I'd rather spend $300 on a spare portable GPS than on a sextant which yields only half of the answer (and in good weather) to the location problem. I have a sextant but never learned to use it.
I visited Greenwich back in 1984 and stood on either side of the 0 meridian. Wonderful trip to London, and then to Plymouth to see the start of an OSTAR race. I saw Eric Tabarly checking the rig high in a bosun chair on his big trimaran, Paul Richard. Warren Luhrs had his 60 ft monohull, Thursday's Child. My girlfriend and I went out on a spectator boat to see the start, and the boats all passed close by. Thursday's Child lept from the water as it sped past us. That boat was fast and finished only 16 hrs after the 1st place multihull. Today, the newest Open 60's have just completed the "Everest of Sailing", round the world non-stop singlehanded in less than 80 days. Breaking all sorts of records along the way like 24hr runs of over 500 miles. Amazing stuff. It played out like a match race. The 2nd place boat after 78 days at sea, was only 3 hrs behind. Chuck Resolute 1990 C&C 34R Atlantic City, NJ ----- Original Message ----- From: "Antoine Rose" <antoine.r...@videotron.ca> To: cnc-list@cnc-list.com Sent: Sunday, January 27, 2013 7:41:41 PM Subject: Re: Stus-List Sextant Chuck, The sextant is just a sophisticated piece of equipment to measure an angle with the precision of a minute, one sixtieth of a degree. A sextant alone will not get you anywhere without a chronometer. Any sailor visiting England should pay a visit to the Greenwich Royal Observatory where you will see the original Harrison chronometers that resolved the problem of longitude (still functioning). If you're using old methods, you also need ephemeris and sight reduction tables. It is easy today to find a free piece of software or even build one yourselves with an Excel spreadsheet. What you need is the ability to understand the time equation and some fairly simple formulas. A good site to start with is Celestaire ( http://www.celestaire.com/ ) whom will provide you with everything you need. You can also find pieces of free software on the net. Since I,m french I can only recommend you a very nice French piece of software you can download for free ( http://olravet.fr/navastro.php ). Very neat, it allows you to also plot the course, because don't forget, one of the key thing to understand is, one reading will not get you a fix. You need at least two reading to plot a position. I have myself two sextants that I cherish ( one old fashioned half mirror and a newer full mirror. Once you learned all the mechanics, this is when you'll discovered that getting a good reading out at sea with a two meter swell is the real challenge. Learning of this is fun, don't get discouraged. Antoine (C&C 30, Cousin) Le 2013-01-27 à 13:24, Chuck S a écrit : My understanding is that the sextant measures the angle between the Moon or Sun and the horizon. If you're careful reading the solar or lunor tables it gives you the latitude where you are. Longitude is something else. I know it requires a good timepiece, but how does one convert the time to longitude? Chuck Resolute 1990 C&C 34R Atlantic City, NJ ----- Original Message ----- From: "Frederick G Street" < f...@postaudio.net > To: cnc-list@cnc-list.com Sent: Sunday, January 27, 2013 12:16:33 PM Subject: Re: Stus-List Mounting chartplotter now Compass Deviation Pricey little bugger… I picked up a slightly used Astra 3B several years ago on eBay, from a guy in Malaysia. Nice wooden box (which I replaced with a Pelican case), and the thing was smack on for calibration. One thing I did do was to replace the old incandescent arc illumination lamp with a red LED; it required some redo of the battery compartment in the handle, but I shouldn't have to change batteries in a long time. Of course, it's not much use on Lake Superior -- as big as the lake is, you can often see the mountains (large hills, actually) on the North and South shores. I had a chance to run it through its paces on a trip to the Pacific Northwest, where we actually had a decent horizon to play with. But I'd need to get familiar with either the paper fix calculation charts or newer celestial nav software in order to get even remotely proficient again. Still, it's a cool gizmo to keep around, in case I ever do get out to bluewater; and it only cost me about $300 plus shipping. Fred Street -- Minneapolis S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( On Jan 26, 2013, at 8:44 PM, Richard Davis < rdavis2...@me.com > wrote: <blockquote> Here is a nice metal sextant. http://www.landfallnavigation.com/-nhu01.html?cmp=pricegrabber&pg=-nhu01&utm_source=-nhu01&utm_medium=shopping%2Bengine&utm_campaign=pricegrabber _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com </blockquote> _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
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