Comparison of Sunrise Positions – The Crazy Things I Think About

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.

Sunrise comparisons on a compass, Edinburgh and Plymouth

Sunrise comparisons on a compass, Edinburgh and Plymouth

 

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.

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20 thoughts on “Comparison of Sunrise Positions – The Crazy Things I Think About

  1. Very interesting…..and one more thing that occasionally occupies my vacant mind; here in the Australian tropics after the winter solstice it takes an awfully long time for the sun to get it’s arse into forward gear and substantially increase daylight hours. During the first few weeks after 22 June daylight increases only a matter of seconds each day until September when the sun really gets a wriggle on and illuminates more minutes each day. The universe is a wonderful place.

    Liked by 1 person

    • I’ve noticed the same thing, AussieStreetPics, but for our winter in December, it always really drags timewise for us to start getting noticeably longer and warmer days! I had always put that down to something psychological, us craving warmer days, thus it takes seemingly longer to happen………….like waiting for Christmas Day as a kid! LOL! 🙂
      But looking at my diagram, there is a difference in angles between the two cities, when comparing the winter solstice to the summer one – it’s 9° for summer and 18° difference in winter, so MAYBE there is a scientific reason for spring seeming to drag in after winter! 🙂
      I have no idea as to why this maybe the case, possibly earths wobble?

      Liked by 1 person

    • I’ve been amazed that even up here in Glenrothes, there is a notable difference Gilly, compared to the length of summer days in Penzance 🙂 Mind you, it also works the other way in winter, the days (well daylight) are even shorter up here.
      It must be amazing to be at a latitude in the summer where the sun doesnt actually set!!! Just imagine it sweeping down towards the horizon, but never going below, and then it sweeps back up into the middle of the sky again!!! Amazing!! 🙂

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  2. I confess I’ve never thought about it in this particular way. But I enjoyed reading about it and I’ve had a crazy thought or two in my long life. 🙂 I think it interesting to look at a map (Do people still look at maps???) and see what countries are on the same longitude/latitude, then think about their climate, etc.

    janet

    Liked by 1 person

    • Thanks Janet 🙂 I must do a follow up post about the difference in angles up to the sun at mid day for each corresponding place, it still amazes me as to how low the sun is up here this time of the year!
      Thanks again Janet, it’s good to know I’m not the only one who does that with a map! It amazes me that we are on a similar latitude to central Labrador in Canada, but because we are such a small land mass in comparison, are weather isn’t anything like as extreme, mores the pity! 🙂

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    • Thanks Jo, glad you understood what I was trying to say…………..I had actually been looking something else up at the time, which led me to thinking about the sun rise positions, and lots of scribbles and angles later, I had my answer…………….and thus decided to share it 🙂

      Liked by 1 person

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