Starship Asterisk*

A Picturesque Equinox Sunset

Explanation: What's that at the end of the road? The Sun. Many towns have roads that run east - west, and on two days each year, the Sun rises and sets right down the middle. Today is one of those days: an equinox. Not only is today a day of equal night ("aequus"-"nox") and day time, but also a day when the sun rises precisely to the east and sets due west. Featured here is a picturesque road in northwest Illinois, USA that runs approximately east -west. The image was taken during the March Equinox of 2015, and shows the Sun down the road at sunset. In many cultures, this March equinox is taken to be the first day of a season, typically spring in Earth's northern hemisphere, and autumn in the south. Does your favorite street run east - west? Tonight, at sunset, you can find out with a quick glance.

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Sun in your eyes! Driving danger! If only road grids had been laid out NE to SW!

I was not expecting to see Roland Christen of Astro-Physics as the photographer. Who knew he has other interests besides making fine APO telescopes?

Actually the day of the equinox does not result in equal lengths for day and night. In theory is should but because of refraction by the Earth's atmosphere, the Sun is above the horizon for several minutes longer.

Guest wrote: ↑Sun Mar 20, 2022 1:31 pm Actually the day of the equinox does not result in equal lengths for day and night. In theory is should but because of refraction by the Earth's atmosphere, the Sun is above the horizon for several minutes longer.

Depends on how you define "day" and "night".

The geometry is easily understood in terms of a point-source sun and a planet with no atmosphere.

Actually I don't really like roads that run exactly east west. I prefer east west roads that are angled some 15 to 20 degrees northwest or southwest. Vice versa the other way for northeast and southeast. That way I don't get the sun in the eyes. It's okay right at sunset as pictured but it is unbearable driving 15 minutes to 30 minutes earlier. I found a solution for driving those due west and east roads though. If you can swing it, drive those roads at high noon, or even wait 15 minutes after sunset or before sunrise to drive. Of course I pity those that can't swing it, like bus drivers, taxi drivers, or pizza deliverers!

heehaw wrote: ↑Sun Mar 20, 2022 9:52 am Sun in your eyes! Driving danger! If only road grids had been laid out NE to SW!

That still leaves a good chunk of people living in Earth's temperate zones driving into the Sun. It just shifts the bad dates to near the solstices.

De58te wrote: ↑Sun Mar 20, 2022 2:04 pm Actually I don't really like roads that run exactly east west. I prefer east west roads that are angled some 15 to 20 degrees northwest or southwest. Vice versa the other way for northeast and southeast. That way I don't get the sun in the eyes. It's okay right at sunset as pictured but it is unbearable driving 15 minutes to 30 minutes earlier. I found a solution for driving those due west and east roads though. If you can swing it, drive those roads at high noon, or even wait 15 minutes after sunset or before sunrise to drive. Of course I pity those that can't swing it, like bus drivers, taxi drivers, or pizza deliverers!

All that does is change the dates when you are driving straight into the Sun.

Spring showers bring rainbows too. Flowers soon to follow!

Chris Peterson wrote: ↑Sun Mar 20, 2022 1:53 pm

Guest wrote: ↑Sun Mar 20, 2022 1:31 pm Actually the day of the equinox does not result in equal lengths for day and night. In theory is should but because of refraction by the Earth's atmosphere, the Sun is above the horizon for several minutes longer.

Depends on how you define "day" and "night".

The geometry is easily understood in terms of a point-source sun and a planet with no atmosphere.

Apparently, there is also the "equilux". But is 'equilux' an officially recognized term? I didn't know it existed until a few days ago. See https://ourplnt.com/equilux-equinox/, which has a helpful video explaining both terms:

I was in northeastern Illinois during last September’s equinox. While I was riding the El near sunset, it occurred to me that it was the day after the equinox, and Chicago’s streets are laid out NS and EW, and sure enough, I got to see Chicagohenge.

The only place I’ve ever lived with a NS-EW grid is Gainesville, Florida, but at the time I had an inaccurate understanding of how the Sun moves from our frame of reference, so checking the Sun on the equinox wasn’t a concept to me.

I also lived in Boston, Massachusetts for a time, which does have one neighborhood laid out EW, but I had been advised to stay out of that neighborhood due to the color of my skin. (“Sundown towns” aren’t just in the USA South.) I did not learn about the nearby MIT Infinite Corridor until I moved away, but MIThenge isn’t equinox-aligned anyway.

Chris Peterson wrote: ↑Sun Mar 20, 2022 2:06 pm

De58te wrote: ↑Sun Mar 20, 2022 2:04 pm Actually I don't really like roads that run exactly east west. I prefer east west roads that are angled some 15 to 20 degrees northwest or southwest. Vice versa the other way for northeast and southeast. That way I don't get the sun in the eyes. It's okay right at sunset as pictured but it is unbearable driving 15 minutes to 30 minutes earlier. I found a solution for driving those due west and east roads though. If you can swing it, drive those roads at high noon, or even wait 15 minutes after sunset or before sunrise to drive. Of course I pity those that can't swing it, like bus drivers, taxi drivers, or pizza deliverers!

All that does is change the dates when you are driving straight into the Sun.

Very true. For example, on Memorial Drive in Cambridge, Massachusetts, the sunset dates are more or less November 11 and January 30. (I don’t know the sunrise dates.)

In Manhattan the sunrise dates are December 5 and January 8, and the sunset dates are May 28 and July 13.

A pretty picture' yes indeed'
but nasty to drive against!
Equinox; you're a pretty sight;
but you blind me, early morning;
and early night!

heehaw wrote: ↑Sun Mar 20, 2022 9:52 am Sun in your eyes! Driving danger! If only road grids had been laid out NE to SW!

there would be a time of year that that would have a bad day also!

Ah yes, Roscoe Road, Rockton, IL. Have Six Vernal Equinox past so quickly?