NavList:

The UK government and parents are fighting hard to prevent children taking their smartphones to bed with them. What a great idea. You’d have thought I’d have learned by now. I woke in the night with a great idea for getting longitude using Kochab and Nocturnal theory, so I stabbed away in the dark on my phone to NavList. Next time I woke, I realised it was 1% brilliant and 99% rubbish. Hopefully, Frank will have binned it by now and it won’t appear [*]. In the cold light of day, I thought on paper and came up with the idea in the diagram below, based upon Kochab’s orbit around the Pole. Having decided your latitude must be around 27N, if you also work out Hc and AZ for Kochab at 01.52 UTC and position = 27N 000EW, you have two solvable spherical triangles of Side, Angle, Side, which will give you two cuts (at least) of Kochab’s orbit round the Pole. The sector of Kochab’s orbit is your longitude.

This would never have won the Longitude Prize, because it relies upon rough bearings and very long ranges, but it’s a start.

Another estimate for longitude is to say that if local time is 2052 and UT is 0152, you must be in a 15degree sector based around 5x15=75W.

[* binned on request! --FER]

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