[LEAPSECS] leap second roundup 2017

[Zefram]

Rob Seaman wrote:
>Of course, civilians will continue to confuse GMT with UTC, so Greenwich
>Mean Time would have to go, too. "London Mean Time" will be unambiguous:

No it wouldn't.  Today we would probably expect "London Mean Time" to
refer to mean solar time on the Greenwich meridian, or at least somewhere
within a second of that.  But predating the Greenwich meridian there
was a different meridian used for official purposes in London, marked
by an obelisk at Kew, with the time scale realised by Kew Observatory.
It's about 0 deg 18' 45" (75 s of time) west of the Greenwich meridian.
"London Mean Time" could well refer to that.

The Kew meridian is described by a comment in the Olson timezone database,
which duly ascribes London a time scale of UT-00:01:15 prior to 1847.
(1847 predates the present Greenwich meridian, but there was already *a*
Greenwich meridian a few metres from the canonical one, and Olson doesn't
work to sufficient resolution to distinguish them.)  It quotes from the
Independent newspaper of 1994-01-17.

-zefram