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    Re: Leap second on December 31
    From: Geoffrey Kolbe
    Date: 2016 Dec 27, 09:25 +0000


    Frank Reed  wrote:

    ​.....​
     Leap seconds are bad for navigation.


    ​Well, there is a contentious statement Frank.Time must be slow for you at this time of year....!

    You are right, of course, that what the leap-second is doing is altering time so that the ephemerides giving the geographical positions of celestial bodies remain (reasonably) correct when using UTC. However, allowing UTC to drift without leap-second corrections will mean that the time will come when we are getting up in the middle of the night, having lunch when dawn is breaking and going to bed when the sun is still high in the sky!

    In some way, civil time has to be maintained as a reasonable match the observed solar day and some mechanism needs to be in place to ensure that this will happen. At the moment it is a relatively small correction that happens once or twice a year, which is often enough that the ability to take the correction into account is built into all the electronic instruments that need to take it into account. Any other correction will be yet-to-be-agreed, large, and happen with such irregularity that it will be bad for all sorts of other reasons other than navigation!

    Geoffrey Kolbe
       
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