NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Patrick O'Brian characters discuss time and longitude
From: Geoffrey Kolbe
Date: 2016 Jun 26, 16:14 +0100
From: Geoffrey Kolbe
Date: 2016 Jun 26, 16:14 +0100
Jack Aubrey's reprimand of his midshipman, with the instance that they should always know their position to within half a minute is hyperbole, but O'Brian seriously declares that on one occasion Jack shot a lunar to determine his position to within a second of longitude.Don Seltzer
I am still recovering from a hangover after celebrating the fact that the British peoples now (once again) have the freedom to choose who rules over them, agree how they should be taxed (and how those taxes
should be spent), and maintain the right to own property.
However, this discussion caught my eye and I wonder if O'Brian is just reflecting how the 18th (very early 19th) century navigator would generally calculate a lunar to the nearest second of arc. With our modern knowledge of statistics and instrument error, we would automatically round this down to a more realistic number to reflect the accuracy of the instrument, the tables and the mathematical methods. However, I suspect that this is a relatively modern attitude to experimental method and the statistical knowledge that underpins had yet to be developed when Aubrey sailed Surprise to the far ends of the Earth.
Geoffrey Kolbe
