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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: How long does Noon last?
From: Joshua Carty
Date: 2026 Feb 6, 06:10 -0800
From: Joshua Carty
Date: 2026 Feb 6, 06:10 -0800
Making sure I understand this. If I use a surveyor's theodolite I can measure the Sun's altitude to to about 5 seconds of arc. You say the duration of LAN is proportional to the square root of the sensitivity. You example gave 11 minutes under the given conditions (Dec -15, Lat 40 N) for sensitivity of 1.0'. Since 5" is twelve times better, then the time would be shorter by squure root of 12 which is 3.464 -- that means duration of noon would be about 3.2 minutes. That's impressively long... Could that be right??
Josh
