NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Determining Elevation with a Sextant
From: George Huxtable
Date: 2002 Mar 3, 13:23 +0000
From: George Huxtable
Date: 2002 Mar 3, 13:23 +0000
I know it's not relevant to navigation, but may I add a few words in reply to Dan Allen's question about finding the elevation of his home above sea level, using a sextant? I agree with those who said that a barometer was a more appropriate instrument, which just needs taking down to the nearest seashore for a comparison, thoroughly tapping it before and after. Another way would be to measure with a good thermometer the temperature of the steam that emerges from his kettle. Or apply the rule that says it's impossible to brew up a good cup of tea above 2000 feet, because it's so sensitive to the water temperature. Trouble with that one is that I have never, ever, succeeding in finding a decent cup of tea anywhere in the USA. Reminds me somewhat of a question in a physics exam, more than 50 years ago. The physics lab was a few storeys up from ground level, and the question asked was how would one find the height of the lab above ground using a mercury barometer. One student (not me) profferred the answer that he would drop the barometer out of the window and, with a stopwatch, time the interval before he heard the crash, then use Newton's laws of motion to derive the height. He got some marks for this, because the examiner conceded that although it wasn't the method that he had in mind, it would probably give a more accurate answer. George Huxtable. >Does anyone have any clever ideas about determining one's elevation above >sea level using a sextant? What if one knows one's >latitude and longitude exactly -- would that help? > >Dan > >Daniel K. Allen >mailto:danallen46@attbi.com >http://home.attbi.com/~danallen46/ ------------------------------ george@huxtable.u-net.com George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. Tel. 01865 820222 or (int.) +44 1865 820222. ------------------------------