# The Solstices and alignment. **URL:** \ **Category:** Factual Questions\ **Created:** [October 8, 2015, 3:25am UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903 "2015-10-08T03:25:08Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [October 8, 2015, 3:25am UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/1 "2015-10-08T03:25:08Z")
The Summer Solstice Sunset aligns 180 degrees with the Winter Solstice Sunrise and v. vs. True? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 8, 2015, 3:46am UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/2 "2015-10-08T03:46:03Z")
Aligns in what sense? What things do you think are aligned? ---
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [October 8, 2015, 4:10am UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/3 "2015-10-08T04:10:26Z")
If you had two upright sticks and some sting, and you used that as a sight to mark the location of the Summer Solstice Sunset on the horizon. Could you then look back down that sight line to predict the Winter Solstice Sunrise? They have to be. ---
**Author:** ![svd678](https://avatars.discourse-cdn.com/v4/letter/s/53a042/32.png) [@svd678](https://boards.straightdope.com/u/svd678)\ **Post date:** [October 8, 2015, 4:13am UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/4 "2015-10-08T04:13:06Z")
Not an astronomer, but until one comes along: I bet sunrise and sunset on one day are for all practical purposes the same angle east and west of true north. That this would be ever be precisely 180 deg. would be true only in one exact latitude, and I don’t know where. Tropic of Capricorn, maybe? One interesting detail is that on the equinoxes day and night are not exactly 12 hours each, because the apparent sunset is distorted by atmosphere. ---
**Author:** ![Carl\_Pham](https://avatars.discourse-cdn.com/v4/letter/c/e9a140/32.png) [@Carl\_Pham](https://boards.straightdope.com/u/Carl_Pham)\ **Post date:** [October 8, 2015, 4:33am UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/5 "2015-10-08T04:33:14Z")
Of course not. Let us assume your latitude is above the Tropic of Cancer, i.e. you’re in some typical North American or European country. Face south. The sun will set on the summer solstice as close to due West as it gets, but somewhat south of it. It will rise on the winter solstice as close to due South as it gets, but at least somewhat east of it. The angle between the two is greater than 90 but less than 180. ---
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [October 8, 2015, 4:43am UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/6 "2015-10-08T04:43:04Z")
No, it has to be; exactly, you can model this with your own hand with a tennis ball around a lamp. Go ahead and put the little sombrero or rings to define the Ecliptic. ---
**Author:** ![glowacks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/glowacks/32/5548_2.png) [@glowacks](https://boards.straightdope.com/u/glowacks)\ **Post date:** [October 8, 2015, 4:48am UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/7 "2015-10-08T04:48:14Z")
> [@Carl\_Pham](#): > > Of course not. Let us assume your latitude is above the Tropic of Cancer, i.e. you’re in some typical North American or European country. Face south. The sun will set on the summer solstice as close to due West as it gets, but somewhat south of it. It will rise on the winter solstice as close to due South as it gets, but at least somewhat east of it. The angle between the two is greater than 90 but less than 180. I don’t see how you get an “of course” out of that. It would seem most reasonable to me that the angle north of west that the sunset is in the summer is the exact same angle, for a given location, that the sunrise in the winter is south of east. Now it’s possibly not quite true due to the eccentricity of the earth’s orbit, the oblateness of the earth’s surface, and possibly other things I’m not considering. However, it still seems reasonable as a good approximation. ---
**Author:** ![Lord\_Feldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lord_feldon/32/341_2.png) [@Lord\_Feldon](https://boards.straightdope.com/u/Lord_Feldon)\ **Post date:** [October 8, 2015, 5:13am UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/8 "2015-10-08T05:13:32Z")
Yes. [This page](http://www.gaisma.com/en/location/new-york-ny.html) has the position of the sun in the sky on the solstices in New York City marked. Sunrise in June is around 60 degrees and sunset in December is around 240 degrees. > [@Carl\_Pham](#): > > The sun will set on the summer solstice as close to due West as it gets, but somewhat south of it. The sun sets _north_ of due west on the June solstice. And the farther north you go, the more pronounced that is, eventually ending up due north when you get to the Arctic Circle. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 8, 2015, 1:33pm UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/9 "2015-10-08T13:33:52Z")
Right, due east or west are on the equinoxes, not the solstices. And the OP is correct, for a flat plain. But if you’ve got an uneven horizon, such as if you’re near mountains (like the Chaco Canyon region of the American Southwest, which I’m guessing inspired the question), then that’ll throw things off a bit. ---
**Author:** ![Freddy\_the\_Pig](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@Freddy\_the\_Pig](https://boards.straightdope.com/u/Freddy_the_Pig)\ **Post date:** [October 8, 2015, 1:57pm UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/10 "2015-10-08T13:57:37Z")
> [@chacoguy](#): > > No, it has to be; exactly, you can model this with your own hand with a tennis ball around a lamp. Go ahead and put the little sombrero or rings to define the Ecliptic. Then . . . why are you asking? The word we’re looking for here is _azimuth_. And yes, the azimuth of the center of the Sun at winter solstice sunrise is 180 degrees offset to the azimuth at summer solstice sunset. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [October 8, 2015, 9:40pm UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/11 "2015-10-08T21:40:37Z")
> [@svd678](#): > > Not an astronomer, but until one comes along: I bet sunrise and sunset on one day are for all practical purposes the same angle east and west of true north. That this would be ever be precisely 180 deg. would be true only in one exact latitude, and I don’t know where. Tropic of Capricorn, maybe? One interesting detail is that on the equinoxes day and night are not exactly 12 hours each, because the apparent sunset is distorted by atmosphere. Not just that. It is also because the definition of sunrise is the first ray of the sun, while that of sunset is the last ray. Since the sun takes at least 2 minutes to set (at the equator, increasing times at higher latitudes) the time between first tangency and last tangency is double counted. Think of two places on earth separated by exactly 180 degrees longitude and at the same latitude. During the entire time the sun is setting at one of those places it is rising at the other so the sun is visible from both places. Then atmospheric refraction has to be added to that. In Montreal on Sept 23, the day length was 12 hours, 8 minutes. As for the question raised in the OP, the eccentricity of the earth’s orbit might make a difference. As a first approximation it has to be correct, but not necessarily exactly so. ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [October 8, 2015, 10:05pm UTC](https://boards.straightdope.com/t/the-solstices-and-alignment/733903/12 "2015-10-08T22:05:59Z")
This shows it fairly well: > **[Sun path](https://en.wikipedia.org/wiki/Sun_path#/media/File:Sun-path-polar-chart.svg)** > > Sun path, sometimes also called day arc, refers to the daily and seasonal arc-like path that the Sun appears to follow across the sky as the Earth rotates and orbits the Sun. The Sun's path affects the length of daytime experienced and amount of daylight received along a certain latitude during a given season. > The relative position of the Sun is a major factor in the heat gain of buildings and in the performance of solar energy systems. Accurate location-specific knowledge of sun path and climat... It is interesting that in the summer sunrise and sunset are north of due east or west, but by 7 AM or so, the sun is back to the south. I guess the extreme of this is above the arctic circle where the sun circles the horizon at summer solstice. The arctic circle provides a nice case for the OP: sunset/rise on the winter solstice is due south, and due north for the summer solstice.