Last summer we had a great trip, coast hopping down to Burnham on Crouch and back again. On the way back we were a bit late, or the storms were a bit early. Anyway we spend some time in the Royal Norfolk and Suffolk Yacht Club waiting for named storms to pass. Russell and I got to talking about cocked hats and uncertainty, which is something I had given popular talks about to sixth form students (You can see me on YouTube ) .
The problem that exercised me was that we had a way to construct the most likely position, the symmedian point, a neat way that we could draw as it is a "triangle centre". But what about an ellipse of equal probability, that is the set of with the same sub of squared distance to the symmedian point. Were the focal points triangle centres? Did the axes of the ellipse go through other triangle centres?
I looked at the Encyclopedia of Triangle Centres but couldn't make any progress. So I asked its editor Clark Kimberling, who asked Peter Moses. These two are the worlds experts on triangle centres. Peter came back with several triangle centres on the major and minor axes. We did some more work together and the result has just been published in The Journal of Navigation. The Geometry of Elliptical Probability Contours for a Fix using Multiple Lines of Position.
Recently I was in the US for work and got to go to Frank Reed's course on Lunars. at Mystic Seaport. I highly recommend the course and as well as historical interest shooting lunars is a great way to practice getting accurate sextant readings.
..so why aren't we sailing? I hurt my knee working on Tui earlier in the year and I am waiting for it to have recovered enough...hopefully soon.
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