Mozambique officially uses LMT?
A month ago was the longest lunar eclipse this century, and it was well visible from Mozambique. I know folks there who forwarded a couple of low resolution versions of information pages that the national meteorological agency issued. Upon looking at them I realized that they were saying that someone at the national meteorological agency believed that each town in Mozambique, including the capitol city Maputo, is running on Local Mean Time. I have attached the images. They are the official announcement from INAM. In a lunar eclipse all points on earth see the same fuzzy shadow events within milliseconds, but all times in the table are offset according to the longitude of the city. I know that cell phones in Mozambique use what tzdb says. I cannot say what outlying villages and people without cell phones use, other than that there is no such thing as precise timing of civil events and transportation departures/arrivals as in most modern cultures. So I cannot say for sure whether this is a mistake, an official doing these calculations the way things used to work, or whether outlying towns still set their clocks using a stick in the ground. I have no contacts to dive deeper into Mozambican government, so I wonder if anyone else can find out more. -- Steve Allen <sla@ucolick.org> WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m
On 2018-08-29 23:16:53 (+0200), Steve Allen wrote:
I know that cell phones in Mozambique use what tzdb says. I cannot say what outlying villages and people without cell phones use, other than that there is no such thing as precise timing of civil events and transportation departures/arrivals as in most modern cultures.
Why spoil the fun with precision? In many parts of the world, time is more like a lake than a river.
So I cannot say for sure whether this is a mistake, an official doing these calculations the way things used to work, or whether outlying towns still set their clocks using a stick in the ground. I have no contacts to dive deeper into Mozambican government, so I wonder if anyone else can find out more.
According to a contact in Maputo, Mozambique really is on UTC+2 all year round as recorded in the tzdb. He points out that "there are a lot of clueless people in key positions" though. Perhaps the official making the lunar eclipse calculations is one of them. I have asked for more insights. :) Philip -- Philip Paeps Senior Reality Engineer Ministry of Information
Steve Allen wrote:
I cannot say for sure whether this is a mistake, an official doing these calculations the way things used to work, or whether outlying towns still set their clocks using a stick in the ground.
tzdb cites a Portuguese decree dated 1911-05-26 <https://dre.pt/application/dir/pdf1sdip/1911/05/12500/23132313.pdf> saying that Mozambique switched to +02 at 1912-01-01 00:00 +02, and I can't find anything online suggesting that this change didn't stick. For what it's worth, the 2012 Atlas de Precipitação Moçambique <http://www.inam.gov.mz/images/Climatologia/ATLAS-INAM-FINAL-Por-Ser-Printada...>, also published by INAM, says on page 2 that precipitation readings are taken at 07:00 UTC (09:00 local time). That being said, Mozambique (or a good chunk of it, anyway) was ruled by Arab traders for centuries, and the Arab world has a history of disagreeing with Western timekeeping, so it's conceivable that solar time survives in some circles.
On 2018-08-30 03:52:32 (+0200), Paul Eggert wrote:
Steve Allen wrote:
I cannot say for sure whether this is a mistake, an official doing these calculations the way things used to work, or whether outlying towns still set their clocks using a stick in the ground.
tzdb cites a Portuguese decree dated 1911-05-26 <https://dre.pt/application/dir/pdf1sdip/1911/05/12500/23132313.pdf> saying that Mozambique switched to +02 at 1912-01-01 00:00 +02, and I can't find anything online suggesting that this change didn't stick. For what it's worth, the 2012 Atlas de Precipitação Moçambique <http://www.inam.gov.mz/images/Climatologia/ATLAS-INAM-FINAL-Por-Ser-Printada...>, also published by INAM, says on page 2 that precipitation readings are taken at 07:00 UTC (09:00 local time).
That being said, Mozambique (or a good chunk of it, anyway) was ruled by Arab traders for centuries, and the Arab world has a history of disagreeing with Western timekeeping, so it's conceivable that solar time survives in some circles.
It may be worth checking whether the individual documenting the lunar eclipse didn't just copy the rubric from the previous eclipse. Arguably, using LMT to document celestial observations makes more sense than using civil time. Not being influenced by politics, it makes observations decades or centuries apart easier to correlate. Philip -- Philip Paeps Senior Reality Engineer Ministry of Information
On Thu 2018-08-30T12:29:30+0200 Philip Paeps hath writ:
It may be worth checking whether the individual documenting the lunar eclipse didn't just copy the rubric from the previous eclipse.
A better check would be to find an official timetable for a recent solar eclipse in Mozambique. The times in that table would say whether it was produced using the actually different contact times in each city or whether the contact times for one city were incorrectly shifted according to the longitude of other cities.
Arguably, using LMT to document celestial observations makes more sense than using civil time. Not being influenced by politics, it makes observations decades or centuries apart easier to correlate.
In the case of Mozambique there is no such astronomical observatory. Every clock would be set (if even that) to some external source of time. -- Steve Allen <sla@ucolick.org> WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m
Steve Allen wrote:
A better check would be to find an official timetable for a recent solar eclipse in Mozambique. The times in that table would say whether it was produced using the actually different contact times in each city or whether the contact times for one city were incorrectly shifted according to the longitude of other cities.
I doubt whether there'd be anything official in Mozambique. I did look for an unofficial time, and found this: http://www.folhademaputo.co.mz/pt/noticias/nacional/mocambique-podera-presen... An English translation is here: http://clubofmozambique.com/news/solar-eclipse-tomorrow-mozambique/ It quotes Mozambican astronomer Hélder Geraldes as saying "the sun will also be visible in the form of a ring in the city Pemba at about 11h58m tomorrow". According to NASA <https://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2016Sep01Agoogle.html>, at Pemba that annular solar eclipse reached its maximum at 09:19:20 UT. It's hard to square that with Geraldes's "11h58m" if tzdb is correct and Mozambique was two hours ahead of UTC. If we go instead by Pemba's local mean time, which I calculate as UTC +02:42:12, the greatest extent would have been at 12:01:32 LMT which is pretty close to Geraldes's stated time. So this is some evidence that an astrononmer in Mozambique uses local mean time. That being said, NASA says that eclipse was only partial in Pemba and you'd have to go north into Quirimbas National Park to get to the eclipse's central line, so Geraldes's prediction doesn't entirely square up with what NASA says, even if we assume Pemba observes LMT. With your contacts in the astronomical world, maybe you can track down Hélder Geraldes and see what he has to say. (Don't all astronomers know each other? :-)
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Steve Allen