skewing of timezones, Equation of time

[gusl]

image of the day:

	0h ± 30m
	1h ± 30m ahead
	2h ± 30m ahead
	3h ± 30m ahead

Difference between sun time and clock time during daylight saving time:

I always found strange how Spain insists on being GMT+1 (which is perfect for more Eastern countries such as Austria and Česko) despite being West of Britain... Presumably, the UK, being powerful and isolated by water, didn't feel the pressure to conform. I wonder when and how Portugal decided to join the UK with GMT.

---

Here's another, which I haven't fully grasped yet:

Equation of time
<< The equation of time is the difference between apparent solar time and mean solar time, both taken at a given place (or at another place with the same geographical longitude) at the same real instant of time. >>

The equation of time — above the axis the dial will appear fast, and below the dial will appear slow.

Comments

[easwaran.livejournal.com]

Interesting how that map makes the assumption that sun time is constant in 15 degree bands around the earth, rather than varying continuously.

[gustavolacerda.livejournal.com]

No, it's just that the shading they use is discretized. I should have the copied the legend.

At first I thought you were talking about
http://en.wikipedia.org/wiki/Equation_of_time

[gustavolacerda.livejournal.com]

I've now included the legend.

[bhudson.livejournal.com]

What I've never understood about DST is that if it's so wonderful, why not switch to it permanently?

[gustavolacerda.livejournal.com]

and why not double or triple DST?

Questions that never get asked in the political process...

[easwaran.livejournal.com]

I'm sure they actually do get asked. However, Daylight Savings Time is such a big issue that I don't think it gets discussed at all very much.

Also, the US is fairly close to permanent DST, being there for about 8 months of the year.

[rdore.livejournal.com]

There's no problem waking up in the dark as long as there is maximal evening sunlight -- that way people will buy more stuff.

[aisa0.livejournal.com]

Personally, I can't imagine why we don't just get up an hour earlier. The clock skew is personally more bothersome to me than changing the time I go to work. I'll totally do the 7-4, just don't make me put up with DST!

[bhudson.livejournal.com]

It's easier to change what the time reads on all the clocks than to change all the habits and regulations that refer to clock times. Switching to permanent DST just means we decide that noon no longer means that the sun is at its nadir.

[gfish.livejournal.com]

The Equation of Time as a 3-dimensional cam, covering the next 10,000 years.

[easwaran.livejournal.com]

That equation of time explains a phenomenon I heard about some time but didn't really understand, which is that the latest sunset and earliest sunrise of the year aren't both on the summer solstice (as one would expect) but are offset by a few days in each direction.