[LEAPSECS] My FOSDEM slides

[Paul Hirose]

On 2015-03-06 11:04, Brooks Harris wrote:
> The "rubber-band era" is
> just entirely irrelevant. Its historically interesting, and may be
> required for some special application concerning that period, but for
> practical "UTC-like" timekeeping its just an historical curiosity.
>
> This fact is somewhat more apparent looking at the IERS publication
> Leap_Second_History.dat, at
> https://hpiers.obspm.fr/eoppc/bul/bulc/Leap_Second_History.dat. There we
> see *no values* before "1 1 1972" - the "rubber-band era" is gone.
> That's correct - the "rubber band era" no long exists.

Since the name of the document is "leap second history", the rate 
offsets and fractional second step adjustments before 1972 aren't 
applicable. They can be found elsewhere at the IERS site:

http://hpiers.obspm.fr/eop-pc/index.php?index=UTC&lang=en

I distribute a Windows astronomical toolbox DLL which includes time 
scale conversions. Since astronomy often requires analysis of old data, 
the DLL can deal with pre-1972 UTC. I won't get into the dispute over 
whether or not that's bona fide UTC! However, the IERS and USNO 
recognize it as such, so I assume the user will expect time conversions 
to work in that era. (I have never needed that capability myself.)