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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: What happened to the leap second?
From: Robert Bernecky
Date: 2017 Jan 1, 12:01 -0800
From: Robert Bernecky
Date: 2017 Jan 1, 12:01 -0800
In the Explanations at the back end of the Nautical Almanac, they explain
The time argument on the daily pages is 12 hr + Greenwich Hour Angle of the mean sun a.k.a GMT, and here denoted UT. This differs from the broadcast time UTC by an amount which, if ignored, introduces an error of up to 0.2' in longitude.
They go on to say leap seconds are introduced so that UTC and "UT" are always within 0.9 seconds of each other. If the leap second was not introduced, you would have to adjust the time read from your watch (i.e. add 1 second) before using it as an entry in the NA.
