[tz] uniform time in Switzerland in second half of 19th century
alois at astro.ch
Wed Sep 11 11:35:41 UTC 2013
On 11.09.13 10:56, Paul Eggert wrote:
> Thanks for looking into that. It confirms that Bern time was not
> exactly GMT+0:30, though we still don't know what it was;
> our current value (derived from one of the Shanks values) is probably
> wrong by a few seconds. It also confirms my suspicion that the 1894
> transition was messy, but it suggests that our 1894 transition
> date of June 1 is correct for Zurich, as my guess is that Zurich was not
> one of the recalcitrant cantons (though it'd be nice to confirm this).
Shanks gives Bern time meridian as 7°26' which is (because he is never
more precise than minutes of arc) as close as he can get to the
coordinates of the old Bern observatory, which are also the base point
of Swiss country topography (Fundamenalpunkt der Schweizer
The Federal regulations say
Der Fundamentalpunkt im Meridianzentrum der alten Sternwarte von Bern
hat die ellipsoidische Länge l = 7°26'22.50" und die ellipsoidische
Breite j = 46°57'08.66".
I.e. the meridian for Bern mean time, which was based on this
observatory, is 7°26'22.50"
Expressed in time, it is 0h29m45.5s
> It'd also be helpful to know what time of day the 1894 transition
> was; we're currently guessing 00:00.
I guess so as well. Lacking other information, it seems sensible to
assume a change of time
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