I have lived in Spain (Santiago de Compostela) and I absolutely loved that in the summer time the sun sets around 10pm. Even in winter time the sun sets around 6:30pm. I have lived in Munich, and it was depressing as hell in winter because the sun sets at around 4pm.
I also hated that in summer in Munich, the sun rised around 5am. I'm not a morning person, I never cared for how much daylight I was getting before 9am (which is more or less the time I wake up)
Daylight in Santiago is only 40 minutes longer during winter solstice. And during summer solstice Munich has longer daylight!
Or not: you cross the border and don't “fix” your watch, because mealtimes, etc, are all shifted an hour in the opposite direction.
Now wondering how accurate a location we can get from the observation of sunrise and sunset from the formula (in the case I got stranded on a desert island :) ).
Ignoring refraction, you have cos(omega_O) = - tan(phi) * tan(delta), where:
- omega_0 is the hour angle at sunrise/sunset (basically the time)
- phi is the observer's longitude
- delta is the sun's declination, which varies over the year.
delta is not exactly sinusoidal but that doesn't seem to be the major problem.
The hour angle at sunrise is
omega_O = arccos(-tan(phi) * tan(delta))
and if delta varies sinusoidally then I think we can wave our hands and say "small angle approximation" to get an approximate sinusoid out the other end, but if tan(phi) gets large enough the approximation breaks down.