The equinox sun rises due east and sets due west

Where does the celestial equator intersect your horizon? ALWAYS at points due east and due west. And the equinox sun is on the celestial equator. That’s why the equinox sun rises due east and due west. Image via Physics.csbsju.edu.

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This year’s September equinox will fall at 00:05 UTC on September 23, 2026. That’s 19:05 p.m. CDT on September 22.

The equinox sun rises due east and sets due west

The sun rises due east and sets due west at the equinox. It might seem counterintuitive. But it’s true no matter where you live on Earth (except at the North and South Poles). Here’s how to visualize it.

To understand the nearly due-east and due-west rising and setting of an equinox sun, you have to think of the reality of Earth in space. First think about why the sun’s path across our sky shifts from season to season. That’s because our world is tilted on its axis with respect to its orbit around the sun.

Now think about what an equinox is. It’s a milestone in Earth’s orbit around the sun. And it’s also an event that happens on the imaginary dome of Earth’s sky. It marks that special moment when the sun crosses the celestial equator — an imaginary line your sky, directly above Earth’s equator. In the case of the September equinox, the sun is moving from north to south, bringing spring and summer to the Southern Hemisphere and fall and winter to the Northern Hemisphere.

So the celestial equator is a great circle dividing the imaginary celestial sphere into its northern and southern halves.

It’s an imaginary line, yet what happens at every equinox is very real. It’s as real as the sun’s passage across your sky each day, and as real as the change of seasons.

Our seasons result from the Earth’s spin axis tilting 23.5 degrees out of the perpendicular to the ecliptic, or Earth’s orbital plane. Image via National Weather Service/ weather.gov.

It’s the same all over the globe

So no matter where you are on Earth (except for the North and South Poles), you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator, the imaginary great circle above the true equator of Earth.

And that’s why the sun rises close to due east and sets close to due west, for all of us, at the equinox. The equinox sun is on the celestial equator. Which means, no matter where you are on Earth, the celestial equator intersects your horizon at due east and due west.

This fact makes the day of an equinox a good day for finding east and west from your yard or favorite site for watching the sky. Just go outside around sunset or sunrise and notice the location of the sun on the horizon with respect to familiar landmarks.

If you do this, you’ll be able to use those landmarks to find those cardinal directions in the weeks and months ahead. Plus, you’ll know those directions long after Earth has moved on in its orbit around the sun.

View at EarthSky Community Photos. | How fast is daytime growing around the equinox? Rupesh Sangoi in Mumbai, India, captured separate images of the sunrise, showing the sun’s movement along the horizon, between the June and December solstices and on the equinoxes. Rupesh wrote: “Did this for over a year, at sunrise.” Glorious composite, Rupesh! Thank you.

Bottom line: The 2026 September equinox occurs at 00:05 UTC on September 23, 2026. That’s 19:05 p.m. CDT on September 22. And the equinox sun rises and sets due east and due west.

Are day and night equal on the equinox?

It’s aurora season. Why more auroras at equinoxes?

Equinox sun above the horizon all day at the poles

The post The equinox sun rises due east and sets due west first appeared on EarthSky.

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Where does the celestial equator intersect your horizon? ALWAYS at points due east and due west. And the equinox sun is on the celestial equator. That’s why the equinox sun rises due east and due west. Image via Physics.csbsju.edu.

Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to EarthSky’s free daily newsletter.

This year’s September equinox will fall at 00:05 UTC on September 23, 2026. That’s 19:05 p.m. CDT on September 22.

The equinox sun rises due east and sets due west

The sun rises due east and sets due west at the equinox. It might seem counterintuitive. But it’s true no matter where you live on Earth (except at the North and South Poles). Here’s how to visualize it.

To understand the nearly due-east and due-west rising and setting of an equinox sun, you have to think of the reality of Earth in space. First think about why the sun’s path across our sky shifts from season to season. That’s because our world is tilted on its axis with respect to its orbit around the sun.

Now think about what an equinox is. It’s a milestone in Earth’s orbit around the sun. And it’s also an event that happens on the imaginary dome of Earth’s sky. It marks that special moment when the sun crosses the celestial equator — an imaginary line your sky, directly above Earth’s equator. In the case of the September equinox, the sun is moving from north to south, bringing spring and summer to the Southern Hemisphere and fall and winter to the Northern Hemisphere.

So the celestial equator is a great circle dividing the imaginary celestial sphere into its northern and southern halves.

It’s an imaginary line, yet what happens at every equinox is very real. It’s as real as the sun’s passage across your sky each day, and as real as the change of seasons.

Our seasons result from the Earth’s spin axis tilting 23.5 degrees out of the perpendicular to the ecliptic, or Earth’s orbital plane. Image via National Weather Service/ weather.gov.

It’s the same all over the globe

So no matter where you are on Earth (except for the North and South Poles), you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator, the imaginary great circle above the true equator of Earth.

And that’s why the sun rises close to due east and sets close to due west, for all of us, at the equinox. The equinox sun is on the celestial equator. Which means, no matter where you are on Earth, the celestial equator intersects your horizon at due east and due west.

This fact makes the day of an equinox a good day for finding east and west from your yard or favorite site for watching the sky. Just go outside around sunset or sunrise and notice the location of the sun on the horizon with respect to familiar landmarks.

If you do this, you’ll be able to use those landmarks to find those cardinal directions in the weeks and months ahead. Plus, you’ll know those directions long after Earth has moved on in its orbit around the sun.

View at EarthSky Community Photos. | How fast is daytime growing around the equinox? Rupesh Sangoi in Mumbai, India, captured separate images of the sunrise, showing the sun’s movement along the horizon, between the June and December solstices and on the equinoxes. Rupesh wrote: “Did this for over a year, at sunrise.” Glorious composite, Rupesh! Thank you.

Bottom line: The 2026 September equinox occurs at 00:05 UTC on September 23, 2026. That’s 19:05 p.m. CDT on September 22. And the equinox sun rises and sets due east and due west.

Are day and night equal on the equinox?

It’s aurora season. Why more auroras at equinoxes?

Equinox sun above the horizon all day at the poles

The post The equinox sun rises due east and sets due west first appeared on EarthSky.

from EarthSky https://ift.tt/48zYh1w