Have you ever wondered about the different positions in which the sun rises, in say Edinburgh, compared to, for example, Plymouth?
Because of the curve of the earth’s surface, us folks north of Hadrian’s Wall get shorter winter days, and longer summer daytime hours, compared with somewhere such as Cornwall/Devon.
This can be proved to be definitely the case, when you look at the angles at which the sun rises in Edinburgh, and compare that with the compass angles at which the sun rises in Plymouth.
If you imagine standing in a very large field of grass, that stretches as far as the horizon in all directions. When you look north, this is at 0° on a compass, east is 90°, south is 180°, west is 270°, and north is 360° or 0° again. If this field was in Edinburgh, in December, the sun would rise at 138°, but in Plymouth, it would rise 18° further to the north at 120°. During the summer, in this field, the sun would rise in Plymouth at 57°, and in Edinburgh at 48°.
To summarise, sunrise and compass positions are
Due North = 0°
Edinburgh June 21st = 48°
Plymouth June 21st = 57°
Due East = 90°
Plymouth Dec 21st = 120°
Edinburgh Dec 21st = 138°
I have shown this graphically on the image below.
The angles are fairly similar for the sunsets, but on the other half of the circle, between 180° (south) and 360°/0° (north).
Going back to the sunrise positions/compass angles, it’s interesting to see that the difference in Edinburgh between summer and winter sunrise positions is exactly 90° (a right angle)!! The difference in Plymouth between summer and winter sunrise positions is only 63°. Technically speaking, the difference at the Equator would be 0° (ie the sun rises at the same point on the horizon whatever the time of the year), and at the North Pole, its infinity?, because in the winter the sun doesn’t rise at all, and in the summer, it doesn’t set!
If I’ve totally confused you, as I’m sure I have, and you have any questions etc, please leave them in the comments below.