Standard Time; is it just me that had it wrong?

[Uricanejack]

Umm..it isn't. If it was American, or indeed British, it would be called "CUT". If it had been all up to the french it would have been "TUC". It ended up as UTC...

And to re-iterate....The OP is *not talking about UTC* nor local civil time as expressed by an offset from UTC.

EDIT: wikipedia link on "UTC" etymology:
https://en.wikipedia.org/wiki/Coordinated_Universal_Time#Etymology

I stand corrected.
The US version was Cordinated Universal Time

 

[Buck Turgidson]

Only nearly - look at the time in Paris (let's say 9 0'oclock) then to get to UTC look at the time zone : UTC-1, so subtract 1 from the time to get UTC. Therefore it is 8 o'clock UTC.

I think it is done so that the simple minded can work out UTC from wherever they are - they don't need to think - since it is -1 they simply subtract one from local time to get UTC.



I have the vague recollection of reading somewhere that UTC and GMT differ by some miniscule amount of one second, but so little that for all practical purposes it makes no difference.

The "Time zone" is +1 not -1.

 

[laika]

Section 1.5 (on p. 12 in my 2016 Reeds) defines terminology.

After defining Zone Time to correspond to Nautical Time Zones (previously referred to) it says:

Caution: land-based time-zone charts often refer to zones the other way round - be careful which one you are using.

Yes definitely confusing but I suppose defined at different times by different committees.

 

[Barnacle Bill]

From Reeds Ocean Handbook:

"There is a convention for naming time zones:
◆ Going to the east of Greenwich, with standard times
ahead of UT, the zones are –1, –2 etc.
◆ In the westerly direction the zones are named +1,
+2 etc.


 Tip
To take an example, in zone –2, you subtract two
hours from the standard time to get UT.
Remember:
◆ The sun rises in the east, so the day starts earlier
to the east.
◆ ‘Plus is west’ on this time zone naming convention."

I don't think it's very logical either, but perhaps this helps a little - to remember how the convention works.

 

[davidej]

UT is GMT

When (in the 18th century) the French and English were arguing about whether the world would adopt Greenwich or Paris Mean Time, the French finally conceded to adopt GMT as long as it wasn't called that.

Hence UT

 

[westernman]

UT is GMT

When (in the 18th century) the French and English were arguing about whether the world would adopt Greenwich or Paris Mean Time, the French finally conceded to adopt GMT as long as it wasn't called that.

Hence UT

And on condition that we adopted the metric system.
We were a bit slow on fulfilling our side of the contract.

 

[davidej]

Have to disagree, the sun rises in Paris an hour before it does in London (or thereabouts) utc - 1. It's just the clocks going the other way doesn't make immediately intuitive sense,

Not true - only a few minutes earlier.

I believe that in the early days of the Common Market, it was decided to standardise the EU on Central European Time ie UT-1

One of many examples of German dominance!

 

[marklucas]

I think it was more that the astronomical tables for noon sights referenced to GMT were far better, and the users of the sights (merchant sailors) made their call quite clear.

 

[Malo37]

I agree. If Paris is UTC-1 and it is 10 oclock at Greenwich then it is 9 oclock at paris! 10-1=9 unless maths has suddenly changed. Nobody writes a mathmatical formula inversely! 10-1 does not equal 11!

Correct. It must be American. Who else uses for example 09:00 pm ?

 

[GHA]

Not true - only a few minutes earlier.
!

It was only an example to show the concept. Actual times don't matter. Go east the sun comes up earlier, it's before your time zone so minus.

 

[mainsail1]

I did not think I was confused about time until I read this thread. Now I need to lie down in a dark room and forget this thread to reset my brain.
Some people make life so complicated.

 

[Humblebee]

Only nearly - look at the time in Paris (let's say 9 0'oclock) then to get to UTC look at the time zone : UTC-1, so subtract 1 from the time to get UTC. Therefore it is 8 o'clock UTC.

I think you've got that back to front, Daedelus. UTC -1 means take an hour off UTC to get the local time, not take an hour off local time to get UTC.
That's my reading of it anyway. As stated by someone above, the sun rises in the east so dawn comes earlier in the east so times are earlier in the east. That's how I remember it anyway.

 

[alan_d]

As stated by someone above, the sun rises in the east so dawn comes earlier in the east so times are earlier in the east.

"Times are earlier in the east" That encapsulates the confusion. Are times earlier in Paris than London because their 8 a.m. (say) comes an hour sooner than in London, or are they later because when it is 8 a.m. in Paris it's only 7 in London?

 

[pmagowan]

Only nearly - look at the time in Paris (let's say 9 0'oclock) then to get to UTC look at the time zone : UTC-1, so subtract 1 from the time to get UTC. Therefore it is 8 o'clock UTC.

I think it is done so that the simple minded can work out UTC from wherever they are - they don't need to think - since it is -1 they simply subtract one from local time to get UTC.



I have the vague recollection of reading somewhere that UTC and GMT differ by some miniscule amount of one second, but so little that for all practical purposes it makes no difference.

Yes but that is a weird way to do things. UTC-1 means (to any sane person IMO) UTC i.e. The time at Greenwich Meridian minus 1 hour. If 10 at Greenwich it is 9 at UTC-1. If we wrote mathmatical formulas in some weird inverse algabraic form that makes 10-1=11 because the answer is what do you need to take 1 from to get 10 then I could understand it, but that is a ludicrous way of doing it. i.e. x-1=10

 

[GHA]

Yes but that is a weird way to do things. UTC-1 means (to any sane person IMO) UTC i.e. The time at Greenwich Meridian minus 1 hour. If 10 at Greenwich it is 9 at UTC-1

It seems perfectly logical, IMHO .. UTC-1 means the *time zone* is an hour before UTC. 11am in Greenwich, France the sun is ahead of UTC, it's before, so their clocks are pointing at noon. Makes perfect sense, but it really is just how you think about it , I suppose. Just a convention.

 

[pmagowan]

It seems perfectly logical, IMHO .. UTC-1 means the *time zone* is an hour before UTC. 11am in Greenwich, France the sun is ahead of UTC, it's before, so their clocks are pointing at noon. Makes perfect sense, but it really is just how you think about it , I suppose. Just a convention.

Yes but that is bonkers. Once you use a mathmatical symbol you need to be prepared for people reading it exactly as it was designed. UTC-1 means that it is UTC minus 1 hour. If minus was meant to mean some kind of non-numerical concept of before in time therefore positive in the standard notation of time then that would be how it is defined! If the number is 0 at Greenwich then every time zone you cross going east should be 0+n because if you were in a instant space ship and moved instantly from one time zone to another that is what the clocks should say. You could say, local time-n=UTC also but that is a silly way of recording something next to a standard. For example, when I measure something at 10 meters long I dont record it as m-9 because the standard is 1m and if you take 9 from 10 it equals the standard!!

 

[RichardS]

Yes but that is bonkers. Once you use a mathmatical symbol you need to be prepared for people reading it exactly as it was designed. UTC-1 means that it is UTC minus 1 hour. If minus was meant to mean some kind of non-numerical concept of before in time therefore positive in the standard notation of time then that would be how it is defined! If the number is 0 at Greenwich then every time zone you cross going east should be 0+n because if you were in a instant space ship and moved instantly from one time zone to another that is what the clocks should say. You could say, local time-n=UTC also but that is a silly way of recording something next to a standard. For example, when I measure something at 10 meters long I dont record it as m-9 because the standard is 1m and if you take 9 from 10 it equals the standard!!

Yes. They should have agreed the names of the time zones as UTC1, UTC2, UTC3 going West and UTC(1), UTC(2), UTC(3) going East and avoided mathematical symbols altogether.

If I ruled the World things would be very different! :encouragement:

Richard

 

[laika]

UTC-1 means the *time zone* is an hour before UTC.

Reeds seems to be using nautical time zone terminology. Nowhere does it use "UTC-1": I would always assume that "UTC-1" was a civil timezone relevant to Praia, not Paris.

"UT" is an ambiguous term which wikipedia tells me can encompass UTC, but when I see it used in a nautical context I always assume (perhaps incorrectly?) it's referring to one of the purely astronomical measures: The Nautical Almanac (not Reeds, the one we use for astro) explicitly defines it's use of "UT" to mean UT1.

I've been trying to get my head round this but I *think* I've come to the conclusion that Reeds is being unnecessarily confusing. It's a reference for coastal navigation, not high seas, so surely civil time is more relevant. In fact its discussion of time seems to say that it is equating "UT" with civil time. So why the need to confuse everyone with nautical "UT-1" notation rather than the more familiar "UTC+1" I don't know. I did send them a query about it yesterday: no reply as yet.

EDIT: (in case of confusion of terms): "UT1" is the most commonly used astronomical time standard, not a mistyping of "UT-1" or "UT+1" which are nautical time zones. People will start caring about the distinction between UT1 and UTC rather more if they abandon leap seconds.

 

[GHA]

Yes but that is bonkers.

In your opinion...

Makes perfect sense to me, timezone is ahead, to the east, UTC is behind, to the west. Not the time displayed on the clocks in that timezone. Which is another thing altogether.
Think of timezones being 15 degrees of greenwich or local hour angles, east the degrees are less, west is more.
In nav terms it makes sense, imho, timezones and hour angles (greenwich or local) are closely related, west is higher, east is lower, it seems you think more in terms of what is being displayed on the clocks rather than in more celestial nav conventions.

ISTM anyone having played around with celestial nav will find it obvious to have east as a negative and west as positive, everyone else probably the opposite.

 

[pmagowan]

In your opinion...

Makes perfect sense to me, timezone is ahead, to the east, UTC is behind, to the west. Not the time displayed on the clocks in that timezone. Which is another thing altogether.
Think of timezones being 15 degrees of greenwich or local hour angles, east the degrees are less, west is more.
In nav terms it makes sense, imho, timezones and hour angles (greenwich or local) are closely related, west is higher, east is lower, it seems you think more in terms of what is being displayed on the clocks rather than in more celestial nav conventions.

ISTM anyone having played around with celestial nav will find it obvious to have east as a negative and west as positive, everyone else probably the opposite.

No, it is simply bonkers, fact!

It is mathematical notation being used to mean something that can not be worked out by general principles but must be learned as a weird exception. Essentially you must be told of it to know of it whereas with basic maths you can easily work out that UTC-1 means UTC minus 1 hour!

The degrees of longitude are easily worked out on first principles also and you don't have to remember any convoluted conventions other than the most basic maths. If you make something relative to something else the only logical notation should reflect this. UTC is a time relative system linked to the prime meridian and all other time zones should be accurately described relative to this. Describing things inversely as UTC relative to local time is silly and is not done in any logical system of standard. We don't do it for meters, litres, pressure, weight, speed etc etc

10 meters does not equal m-9
10mph does not equal mph-9
10 atmospheres does not equal atm-9
Etc