[tz] question re zone America/Punta_Arenas in Chile
Tim Parenti
tim at timtimeonline.com
Wed Mar 16 03:24:29 UTC 2022
I've prepared the attached patches to address and further document this
divergence.
0001 reverts the data change portion of the errant commit
6d6a21f592c421dcebf39b07a6271d68187cfa15 published on Saturday 2022-03-12.
0002 significantly expands our commentary on Chilean transitions in 1946
and 1947 and also adjusts LMT/SMT to match Chilean law. In particular,
even recent Chilean law still refers to time reckoned as "the meridian of
the Astronomical Observatory of Lo Espejo, advanced by 42 minutes and 45
seconds"
https://www.diariooficial.interior.gob.cl/publicaciones/2018/11/23/42212/01/1498738.pdf
While preparing these patches, I also noticed this in our commentary:
# From Paul Eggert (2019-09-01):
# The above says the Magallanes exception expires 2022-04-02 at 24:00,
# so in theory, they will revert to -04/-03 after that.
# For now, assume that they will not revert,
# since they have extended the expiration date once already.
So there's a decent chance we'll be hearing from Chile soon anyway.
In any case, the attached patches (along with a couple small clerical
patches) are now installed in the development repository.
--
Tim Parenti
On Mon, 14 Mar 2022 at 23:27, Tim Parenti <tim at timtimeonline.com> wrote:
>
> On Fri, 11 Mar 2022 at 12:39, Alois Treindl via tz <tz at iana.org> wrote:
>
>> I wonder on which basis the 1946/47 DST was left out for Puntas_Arenas?
>> Is that documented somewhere?
>>
> Although it doesn't appear to have been documented in our extended
> commentary, there's indeed a clue in the short line-comment that reads
> "central Chile".
>
> It can sometimes get confusing looking at UNTIL lines, but the only place
> the UT offsets of the two zones actually deviate in our 2021e data is the
> roughly six-week period from through 1946-07-15 through 1946-08-31,
> inclusive. Compare the extract from America/Punta_Arenas:
> -5:00 - -05 1942 Aug 1
> -4:00 - -04 1947 Apr 1
> and America/Santiago:
> -5:00 - -05 1942 Aug 1
> -4:00 - -04 1946 Jul 15
> -4:00 1:00 -03 1946 Sep 1 # central Chile
> -4:00 - -04 1947 Apr 1
>
> So what happened on 1946-07-15? Well, sure enough, an emergency decree
> which only applied to the central part of the country:
>
> https://www.diariooficial.interior.gob.cl/versiones-anteriores/do-h/19460715/#page/1
> Núm. 3,891. Adelanta la hora oficial en el territorio nacional comprendido
> entre las provincias de Coquimbo y Concepción, inclusives, por el plazo de
> 30 días
> No. 3,891. Advancing the official time in the national territory between
> the provinces of Coquimbo and Concepción, inclusive, for a period of 30 days
>
> Specifically (my Google-assisted translation):
> "In the national territory between the provinces of Coquimbo and
> Concepción, inclusive, the Official Time will be advanced by sixty minutes,
> for a period of 30 days, starting from 24:00 on July 14 [of the current
> yaer]."
>
> That would include Santiago, which advanced to -03, but did not reach so
> far south as Magallanes, which would have stayed on -04.
>
> The decree contemplated "[t]hat this advancement of the Official Time,
> even though it has been proposed for the cities of Santiago and Valparaíso
> only, must be agreed with that of other cities, due to the connection of
> various activities that require it, such as, for example, the operation of
> rail services".
>
> As the 30 days reached their expiry, the time change was extended:
>
> https://www.diariooficial.interior.gob.cl/versiones-anteriores/do-h/19460814/#page/1
> Núm. 4,506. Prorroga hasta el 31 del mes en curso la vigencia del cambio
> de hora oficial en el territoria nacional comprendido entre las provincias
> de Coquimbo y Concepción, inclusives
> No. 4,506. Extending until the 31st of the current month [August] the
> validity of the official time change in the national territory between the
> provinces of Coquimbo and Concepción, inclusive
>
> Later in August, a bill reunified the country's clocks:
>
> https://www.diariooficial.interior.gob.cl/versiones-anteriores/do-h/19460828/#page/1
> (translated excerpt)
> "The official time for the entire Republic will be from 1 September to 31
> March of each year, the meridian of the Astronomical Observatory of Lo
> Espejo, advanced by 42 minutes and 45 seconds, which corresponds to the
> 20th time zone, four hours west of Greenwich, and will be called Summer
> Time. From 1 April to 31 August, it will be that of the Lo Espejo
> Observatory Meridian delayed by 17 minutes and 15 seconds, which
> corresponds to the 19th time zone, five hours west of Greenwich, and will
> be called Winter Time."
>
> Technically, this bill came into force "from the date of its publication",
> but given that that was sufficiently close to the 1946-08-31 expiry of the
> extended emergency act anyway, and the rest of the country would have
> already been on -04, it seems just as likely that clocks changed in the
> center of the country on 1946-08-31 24:00, as previously scheduled. Under
> this law, the 1946/1947 observance of Summer Time at -04 lasted for all six
> of its months, but our data show the observance of Winter Time at -05 was
> cut short after about seven weeks on 1947-05-21 when -04 was adopted as the
> new Standard Time.
>
> This differs somewhat from our horaoficial.cl source
>
> https://web.archive.org/web/20120306042032/http://www.horaoficial.cl/ing/horaof_ing.html
> which implies the divergence *began* on 1946-09-01 rather than *ended* on
> it, but the legal texts seem clear to me: Our 2021e data is right.
>
>
> On Sat, 12 Mar 2022 at 14:44, Paul Eggert via tz <tz at iana.org> wrote:
>
>> Thanks for pointing out what appears to be a transcription error when I
>> created America/Punta_Arenas in 2016. I installed the attached proposed
>> patch into the development version.
>
>
> Unfortunately, I believe this means that the data change here should at
> least be reverted. We can also better specify the transition dates and
> expand commentary as necessary.
>
> And while it's before our 1970 cutoff for zone creation, those tracking
> expanded pre-1970 data should be keen to only put the correct areas on -03
> for these few weeks in 1946. It really was only the middle bit on -03, not
> the south, and not the north.
>
> --
> Tim Parenti
>
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