corrected DST data Switzerland 1941 and 1942, final report
Hello I have researched the DST usage in Switzerland during the 1940ies. As I wrote in an earlier message, I suspected the current tzdata values to be wrong. This is now verified. I have found copies of the original ruling by the Swiss Federal government, in 'Eidgenössische Gesetzessammlung 1941 and 1942' (Swiss federal law collection) and attach GIF copies of the two pages for 1941. DST began on Monday 5 May 1941, 1:00 am by shifting the clocks to 2:00 am DST ended on Monday 6 Oct 1941, 2:00 am by shifting the clocks to 1:00 am. DST began on Monday, 4 May 1942 at 01:00 am DST ended on Monday, 5 Oct 1942 at 02:00 am There was no DST in 1940, I have checked the law collection carefully. It is also indicated by the fact that the 1942 entry in the law collection points back to 1941 as a reference, but no reference to any other years are made. Newspaper articles I have read in the archives on 6 May 1941 reported about the introduction of DST (Sommerzeit in German) during the previous night as an absolute novelty, because this was the first time that such a thing had happened in Switzerland. I have also checked 1916, because one book source (Gabriel, Traite de l'heure dans le monde) claims that Switzerland had DST in 1916. This is false, no official document could be found. Probably Gabriel got misled by references to Germany, which introduced DST in 1916 for the first time. The tzdata rules for Switzerland must be changed to: Rule Swiss 1941 1942 - May Mon>=1 1:00 1:00 S Rule Swiss 1941 1942 - Oct Mon>=1 2:00 0 - The 1940 rules must be deleted. One further detail for Switzerland, which is probably out of scope for most users of tzdata: The zone file Zone Europe/Zurich 0:34:08 - LMT 1848 Sep 12 0:29:44 - BMT 1894 Jun #Bern Mean Time 1:00 Swiss CE%sT 1981 1:00 EU CE%sT describes all of Switzerland correctly, with the exception of the Cantone Geneve (Geneva, Genf). Between 1848 and 1894 Geneve did not follow Bern Mean Time but kept its own local mean time. To represent this, an extra zone would be needed. Two GIF files are attached. best regards Alois -- || Alois Treindl, Astrodienst AG, mailto:alois@astro.com || Zollikon/Zurich, Switzerland || Free astrological charts at http://www.astro.com/ || SWISS EPHEMERIS Free Edition at http://www.astro.com/swisseph/
Thanks very much for that Swiss info; it sure is authoritative! We need to correct the zone files accordingly. I like the detail about the Cantone Geneve (Geneva, Genf) between 1848 and 1894; we should put that into a comment. By the way, was Bern Mean Time actually exactly 29 minutes and 44 seconds ahead of GMT? Our only source for that is Shanks.
Paul Eggert wrote:
By the way, was Bern Mean Time actually exactly 29 minutes and 44 seconds ahead of GMT? Our only source for that is Shanks.
I have not seen an official document yet which defines the Swiss time standard of 1854 - 1894. Maybe I will make another trip to the Zurich central library to check the law collection. Traditionally the locations of astronomical oberservatories were used as reference point. The 'Alte Sternwarte Bern' (old Bern observatory) was used as the reference point for the national swiss geodetic system of 1903, Its location is given in http://www.swisstopo.admin.ch/ as Latitude = 46° 57' 08.66" geogr. Breite des Nullpunkts in Bern (**) Longitude = 7° 26' 22.50" geogr. Länge des Nullpunkts in Bern (**) This longitude converted to time gives 29m45.5s which is 1.5 seconds off the Shanks value. As far as I know Thomas Shanks (whom I personally met in 1987) has always second values which are a multiple of 4, and I presume this comes from the fact that he rounded longitude to integer minutes. He gives as longitude of Bern 7°26' and therefore arrives at 29m44s. -- || Alois Treindl, Astrodienst AG, mailto:alois@astro.com || Zollikon/Zurich, Switzerland || Free astrological charts at http://www.astro.com/ || SWISS EPHEMERIS Free Edition at http://www.astro.com/swisseph/
This is a minor issue. tzcode2011g contains the man file zic.8 which in turn contains example cases for rules and zones, among them Switzerland. The example rules for Switzerland contain still two lines for 1940, which have been removed in tzdata/europe since tzdata2008h. They should probably also be removed in zic.8 and the other examples should also be checked whether they are still current. A reader of the zic.8 man page who compares it with data from zdump might otherwise get confused.
participants (2)
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Alois Treindl
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Paul Eggert