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0 pointsdalke13y ago0 comments

You already have to do a latitude adjustment, and that's much more complicated than longitude.

I got quite disoriented once going to the southern hemisphere because my northern hemisphere-trained instincts though that the sun should be towards the south at noon, when it's actually to the north.

In Sweden, I had to really adjust my calculations based on the season. If it's summer then the sun sets almost in the north. In the winter, sunset is much closer to the south.

That said, I agree with you. It's easier to say "in the US, if the time is 12:00 then the sun is roughly south" than to have to localize it for the different UTC times for noon in Hawaii through to Florida.

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T-hawk13y ago

You don't have to do a latitude adjustment if you anchor your expected position of the sun to time rather than sunrise/sunset. The mean sun is always due east at 6 AM, due south at 12 noon, due west at 6 PM, due north at midnight (usually below the horizon except for arctic summer.) And you can interpolate between those, south by southwest is 3 PM and so on.

Just shift the time points an hour for daylight savings if necessary, or flip north and south for the southern hemisphere. You don't have to calculate from latitude.

dalkeOP13y ago

I'll grant you that I'm in a somewhat unusual circumstance. Today, sunrise was at 8.49, with azimuth 133 degrees, and sunset was at 15.49 at 227 degrees. It's easier to remember that it rises in the SE and sets in the SW this time of year than to estimate where under the horizon it would be at 6AM or 6PM.

In summer, at 22.00, it's also easier to think that there's another 30 minutes to sunset, which will be in the NNW than it is to figure out where it was 4 hours previous. The knowledge of where the sun will rise at 03.30 is helpful when setting up a tent, since it's easier to sleep when in the shade.

Though since I've found I'm rather bad at estimating angular width, I pull out a compass instead of eyeballing it.

eric_the_read13y ago

That was exactly the problem that started time zones in the first place! Every town had their own definition of noon, which made it impossible to schedule trains across long distances. Time Lord, about Sanford Fleming is a great book about how time zones came to be: http://www.amazon.com/Time-Lord-Sandford-Creation-Standard/d...

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