Circumpolar stars never rise or set and depend on latitude

View at EarthSky Community Photos. | Rui Santos in Amor, Leiria, Portugal, shared this composite image of star trails on February 16, 2025, and wrote: “We can’t feel it, but everything is in motion. Everything moves, even when it seems still. And nature is never the same twice; it is constantly changing, in a vivid and silent way.” Thank you, Rui! Read more about circumpolar stars below.

EarthSky’s 2026 lunar calendar shows the moon phase for every day of the year. Get yours today!

Circumpolar stars circle the celestial pole

The closer you are to either of Earth’s poles, the more circumpolar stars you see. Circumpolar stars neither rise nor set but stay above the horizon at all hours of the day, every day of the year. Even when you can’t see them – when the sun is out and it’s daytime – these stars are up there. They are circling endlessly around the sky’s north or south celestial pole.

For instance, the stars of the famous Big Dipper asterism are circumpolar at all latitudes north of 41 degrees north latitude, which includes the northern half of the mainland United States and most of Europe.

The Big Dipper and the W-shaped constellation Cassiopeia circle around Polaris, the North Star, in a period of 23 hours and 56 minutes. The Dipper is circumpolar at 41 degrees north latitude, and all latitudes farther north. Image via Mjchael/ Wikipedia (CC BY-SA 2.5).

No circumpolar stars at Earth’s equator

How many circumpolar stars appear in your sky depends on where you are. For example, at Earth’s North and South Poles, every visible star is circumpolar. That is, at Earth’s North Pole, every star north of the celestial equator is circumpolar, while every star south of the celestial equator stays below the horizon. On the other hand, at the Earth’s South Pole, it’s the exact opposite. That’s where every star south of the celestial equator is circumpolar, whereas every star north of the celestial equator remains beneath the horizon.

Meanwhile at the Earth’s equator, no star is circumpolar because all the stars rise and set daily in that part of the world. You can (theoretically) see every star in the night sky over the course of one year. Of course, things like clouds and horizon haze get in the way.

Circumpolar stars and where you live

Places between the equator and poles have some stars that are circumpolar, some stars that rise and set daily (like the sun), and some stars that remain below the horizon all year round. In short, the closer you are to the North or South Pole, the greater the circle of circumpolar stars; the closer you are to the Earth’s equator, the smaller the circle of circumpolar stars.

Here is how to determine what is circumpolar from your location. Subtract your latitude from 90 and you get the declination of the objects that barely skim above your northern (or southern) horizon. For instance, from a latitude of 40 degrees north, everything north of a declination of +50° is circumpolar. From the Southern Hemisphere, at a latitude of 20° south, then everything south of -70° declination is circumpolar, above your southern horizon.

We in the Northern Hemisphere are lucky to have a moderately bright star, Polaris, nearly coinciding with the north celestial pole: the point in the sky that’s at zenith (straight overhead) at the Earth’s North Pole.

Polaris at the center of the circle

Draw an imaginary line straight down from Polaris, the North Star, to the horizon, and presto, you have what it takes to draw out the circle of circumpolar stars in your sky.

For people in the Northern Hemisphere, Polaris nearly pinpoints the center of the great big circle of circumpolar stars on the sky’s dome. And the imaginary vertical line from Polaris to the horizon depicts the radius measure. (See the chart below, which has this line drawn in for you.)

So let your arm serve as a circle compass, enabling you to envision the circle of circumpolar stars with your mind’s eye. Closer to the equator, the circle of circumpolar stars grows smaller; nearer to the North Pole (or South Pole) the circle of circumpolar stars grows larger.

In the Northern Hemisphere, an imaginary vertical line from the north celestial pole to your horizon serves as a radius measure for the circle of circumpolar stars in your sky. The closer you are to the Earth’s North Pole, the closer the north celestial pole is to your zenith (overhead point). Chart via EarthSky.

Circumpolar stars in Southern Hemisphere

This technique for locating the circle of circumpolar stars works in the Southern Hemisphere, as well. However, it’s trickier to star-hop to the south celestial pole: the point on the sky’s dome that’s at zenith over the Earth’s South Pole. Thus, practiced stargazers in the Southern Hemisphere rely on the Southern Cross, and key stars, to star-hop to the south celestial pole.

The Southern Cross is circumpolar anywhere south of 35 degrees south latitude; yet, in the Northern Hemisphere, it’s the W or M-shaped constellation Cassiopeia that’s circumpolar at all places north of 35 degrees north latitude.

Polaris and Cassiopeia

By the way, Cassiopeia lies on the opposite side of Polaris from the Big Dipper. So, from mid-northern latitudes, the Big Dipper and Polaris help you to locate Cassiopeia.

If Cassiopeia is circumpolar in your sky, then the Southern Cross never climbs above your horizon. Conversely, if the Southern Cross is circumpolar in your sky, then the constellation Cassiopeia never climbs above the horizon.

As seen from the tropics (and a part of the subtropics), neither the Southern Cross nor Cassiopeia is circumpolar. From this part of the world, the Southern Cross rises over the southern horizon when Cassiopeia sinks below the northern horizon. Conversely, Cassiopeia rises over the northern horizon when the Southern Cross sinks below the southern horizon.

Circumpolar star trail gallery

View at EarthSky Community Photos. | Eddie Little of North Carolina captured the stars circling around Polaris, the North Star, on January 2, 2025, and wrote: “I had a mostly cloudless, nearly moonless night on one of the longest nights of the year. Approximately 12 hours of shooting. 1667 individual 30 second exposures were merged with star trails.” Thank you, Eddie! Polaris, our North Star, is in the center of the star trails.

View at EarthSky Community Photos. | Amrinderjit Singh captured these star trails from Pangong Lake, nestled 14,300 feet (4,350 meters) above sea level in the Himalayas. Amrinderjit wrote: “Behold the mesmerizing dance of stars. As the night falls, it transforms into a celestial canvas, painted with streaks of yellow, blue, and pink, courtesy of the star trails swirling above. Each streak represents the movement of Earth beneath the starlit sky, a silent yet profound reminder of our place in the cosmos. Capturing this moment was a blend of patience and wonder as I marveled at nature’s masterpiece unfolding before my eyes.” Thanks, Amrinderjit!

Steve Torrence made this video of circumpolar stars from near the equator on June 21, 2016. Video via Wikimedia Commons (CC BY 4.0).

Bottom line: Circumpolar stars stay above the horizon all hours of the day, every day of the year. Although you can’t see them, they’re up even in the daytime.

Polaris is the present-day North Star of Earth

Read more: Use the Southern Cross to find due south

The post Circumpolar stars never rise or set and depend on latitude first appeared on EarthSky.

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View at EarthSky Community Photos. | Rui Santos in Amor, Leiria, Portugal, shared this composite image of star trails on February 16, 2025, and wrote: “We can’t feel it, but everything is in motion. Everything moves, even when it seems still. And nature is never the same twice; it is constantly changing, in a vivid and silent way.” Thank you, Rui! Read more about circumpolar stars below.

EarthSky’s 2026 lunar calendar shows the moon phase for every day of the year. Get yours today!

Circumpolar stars circle the celestial pole

The closer you are to either of Earth’s poles, the more circumpolar stars you see. Circumpolar stars neither rise nor set but stay above the horizon at all hours of the day, every day of the year. Even when you can’t see them – when the sun is out and it’s daytime – these stars are up there. They are circling endlessly around the sky’s north or south celestial pole.

For instance, the stars of the famous Big Dipper asterism are circumpolar at all latitudes north of 41 degrees north latitude, which includes the northern half of the mainland United States and most of Europe.

The Big Dipper and the W-shaped constellation Cassiopeia circle around Polaris, the North Star, in a period of 23 hours and 56 minutes. The Dipper is circumpolar at 41 degrees north latitude, and all latitudes farther north. Image via Mjchael/ Wikipedia (CC BY-SA 2.5).

No circumpolar stars at Earth’s equator

How many circumpolar stars appear in your sky depends on where you are. For example, at Earth’s North and South Poles, every visible star is circumpolar. That is, at Earth’s North Pole, every star north of the celestial equator is circumpolar, while every star south of the celestial equator stays below the horizon. On the other hand, at the Earth’s South Pole, it’s the exact opposite. That’s where every star south of the celestial equator is circumpolar, whereas every star north of the celestial equator remains beneath the horizon.

Meanwhile at the Earth’s equator, no star is circumpolar because all the stars rise and set daily in that part of the world. You can (theoretically) see every star in the night sky over the course of one year. Of course, things like clouds and horizon haze get in the way.

Circumpolar stars and where you live

Places between the equator and poles have some stars that are circumpolar, some stars that rise and set daily (like the sun), and some stars that remain below the horizon all year round. In short, the closer you are to the North or South Pole, the greater the circle of circumpolar stars; the closer you are to the Earth’s equator, the smaller the circle of circumpolar stars.

Here is how to determine what is circumpolar from your location. Subtract your latitude from 90 and you get the declination of the objects that barely skim above your northern (or southern) horizon. For instance, from a latitude of 40 degrees north, everything north of a declination of +50° is circumpolar. From the Southern Hemisphere, at a latitude of 20° south, then everything south of -70° declination is circumpolar, above your southern horizon.

We in the Northern Hemisphere are lucky to have a moderately bright star, Polaris, nearly coinciding with the north celestial pole: the point in the sky that’s at zenith (straight overhead) at the Earth’s North Pole.

Polaris at the center of the circle

Draw an imaginary line straight down from Polaris, the North Star, to the horizon, and presto, you have what it takes to draw out the circle of circumpolar stars in your sky.

For people in the Northern Hemisphere, Polaris nearly pinpoints the center of the great big circle of circumpolar stars on the sky’s dome. And the imaginary vertical line from Polaris to the horizon depicts the radius measure. (See the chart below, which has this line drawn in for you.)

So let your arm serve as a circle compass, enabling you to envision the circle of circumpolar stars with your mind’s eye. Closer to the equator, the circle of circumpolar stars grows smaller; nearer to the North Pole (or South Pole) the circle of circumpolar stars grows larger.

In the Northern Hemisphere, an imaginary vertical line from the north celestial pole to your horizon serves as a radius measure for the circle of circumpolar stars in your sky. The closer you are to the Earth’s North Pole, the closer the north celestial pole is to your zenith (overhead point). Chart via EarthSky.

Circumpolar stars in Southern Hemisphere

This technique for locating the circle of circumpolar stars works in the Southern Hemisphere, as well. However, it’s trickier to star-hop to the south celestial pole: the point on the sky’s dome that’s at zenith over the Earth’s South Pole. Thus, practiced stargazers in the Southern Hemisphere rely on the Southern Cross, and key stars, to star-hop to the south celestial pole.

The Southern Cross is circumpolar anywhere south of 35 degrees south latitude; yet, in the Northern Hemisphere, it’s the W or M-shaped constellation Cassiopeia that’s circumpolar at all places north of 35 degrees north latitude.

Polaris and Cassiopeia

By the way, Cassiopeia lies on the opposite side of Polaris from the Big Dipper. So, from mid-northern latitudes, the Big Dipper and Polaris help you to locate Cassiopeia.

If Cassiopeia is circumpolar in your sky, then the Southern Cross never climbs above your horizon. Conversely, if the Southern Cross is circumpolar in your sky, then the constellation Cassiopeia never climbs above the horizon.

As seen from the tropics (and a part of the subtropics), neither the Southern Cross nor Cassiopeia is circumpolar. From this part of the world, the Southern Cross rises over the southern horizon when Cassiopeia sinks below the northern horizon. Conversely, Cassiopeia rises over the northern horizon when the Southern Cross sinks below the southern horizon.

Circumpolar star trail gallery

View at EarthSky Community Photos. | Eddie Little of North Carolina captured the stars circling around Polaris, the North Star, on January 2, 2025, and wrote: “I had a mostly cloudless, nearly moonless night on one of the longest nights of the year. Approximately 12 hours of shooting. 1667 individual 30 second exposures were merged with star trails.” Thank you, Eddie! Polaris, our North Star, is in the center of the star trails.

View at EarthSky Community Photos. | Amrinderjit Singh captured these star trails from Pangong Lake, nestled 14,300 feet (4,350 meters) above sea level in the Himalayas. Amrinderjit wrote: “Behold the mesmerizing dance of stars. As the night falls, it transforms into a celestial canvas, painted with streaks of yellow, blue, and pink, courtesy of the star trails swirling above. Each streak represents the movement of Earth beneath the starlit sky, a silent yet profound reminder of our place in the cosmos. Capturing this moment was a blend of patience and wonder as I marveled at nature’s masterpiece unfolding before my eyes.” Thanks, Amrinderjit!

Steve Torrence made this video of circumpolar stars from near the equator on June 21, 2016. Video via Wikimedia Commons (CC BY 4.0).

Bottom line: Circumpolar stars stay above the horizon all hours of the day, every day of the year. Although you can’t see them, they’re up even in the daytime.

Polaris is the present-day North Star of Earth

Read more: Use the Southern Cross to find due south

The post Circumpolar stars never rise or set and depend on latitude first appeared on EarthSky.

from EarthSky https://ift.tt/pMhWnwJ