[LEAPSECS] alternative to smearing

[Preben Nørager]

On Mon Jan 9 13:49:20 EST 2017 Gerry Ashton wrote:


"As far as I can tell the Julian Period is no longer in use, although the
derivatives, Julian date and Julian day number, are widely used in science
and astronomy."


The julian period is the number of julian days since the start of the
julian era, either January 1, 4713 BC, in the proleptic julian, or
-4713-11-25 in the proleptic gregorian calendar. To say that the julian
period is no longer in use, but the julian day numbers are, makes little
sense to me, because the julian day number is the result of the julian
period.

2017-01-09 20:58 GMT+01:00 Zefram <zefram at fysh.org>:

> Preben Norager wrote:
> >                                 if leap seconds are abolished, then the
> >gregorian calendar is implicitly forced on, because of the implicit
> >connection between the international atomic timescale, and the gregorian
> >calendar.
>
> There is no such connection.  TAI times are conventionally described by
> dividing up the time scale into notional days, which are then labelled
> according to the Gregorian calendar.  But this is *only* convention,
> and two separate conventions at that.  TAI's actual nature is of a linear
> sequence of seconds, which one can label in any regular manner at all.
>
> If the use of UTC (with leap seconds) were abolished for civil time,
> in favour of a TI time scale that amounts to TAI plus some fixed offset,
> then it would of course be necessary for TI to be divided up into days.
> This would be required in order to plug TI into the existing civil
> horological mechanisms that have evolved with UT.  It would look much
> like the same as how TAI is conventionally represented.  But even
> with the division into days having become necessary rather than merely
> conventional, there is still a totally free choice as to which calendar
> to use to label the days.  Indeed, it is inevitable that each locality
> adopting TI would continue to use whatever calendar it had formerly used
> with UT.
>
> I am mystified as to how you think the choice of time scale here forces
> the choice of calendar.
>
> -zefram
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