Polaris: What Is the North Star and How to Find It?
Polaris, also known as the North Star, is a moderately bright star visible year-round from most of the Northern Hemisphere. Although it is not the brightest star in the sky, it lies less than 1° from the North Celestial Pole, making it one of the easiest celestial landmarks for finding north.
Use the Sky Tonight app to quickly find Polaris in the sky from wherever you are. Read on to learn how to locate it using the Big Dipper, find true north, and even estimate your latitude.
Contents
- Polaris (Alpha Ursae Minoris) — key star facts
- What is the North Star?
- How to find the North Star
- Why does Polaris appear fixed in the sky?
- How to use Polaris for navigation
- Is Polaris a single star?
- Why does Polaris change brightness?
- What have astronomers recently discovered about Polaris?
- Has Polaris always been the North Star?
North Star: Frequently Asked Questions
- What is Polaris?
- What constellation contains the North Star?
- Is the North Star part of the Big Dipper?
- Is the North Star the brightest star?
- Does Polaris always point north?
- Can you see Polaris from the equator?
- Can you see Polaris from the Southern Hemisphere?
- Is there a South Star?
- How far away is Polaris?
- Polaris, the North Star: Bottom line
Polaris (Alpha Ursae Minoris) — key star facts
- Official designation: Alpha Ursae Minoris, α UMi
- Common names: Polaris, North Star, Pole Star
- Catalog designations: HIP 11767, HR 424, HD 8890, TYC 4628-237-1
- Constellation: Ursa Minor
- Star type: Triple system; the visible primary, Polaris Aa, is an F8 Ib yellow-white supergiant and a classical Cepheid variable
- Right ascension: 02h 31m 49.08s (ICRS, J2000)
- Declination: +89° 15′ 50.8″ (ICRS, J2000)
- Apparent magnitude: About 2.0; its small pulsations are not obvious to the naked eye
- Mass of Polaris Aa: 5.13 ± 0.28 solar masses
- Mean radius of Polaris Aa: 46.27 ± 0.42 solar radii
- Surface temperature of Polaris Aa: About 6,015 K
- Distance from Earth: 136.90 ± 0.34 parsecs, or about 447 light-years
- Pulsation period: About 3.97 days
- Orbital period of Polaris Aa and Ab: About 30 years
- Rotation period of Polaris Aa: 100.29 ± 0.19 days
Polaris looks like a single star to the unaided eye, but it is actually a system of three stars. Nearly all the visible light comes from Polaris Aa, a yellow-white supergiant that rhythmically expands and contracts.
What is the North Star?
The North Star is the bright, easily visible star nearest to the North Celestial Pole — the point in the sky directly above Earth’s North Pole. Today, the North Star is Polaris, also known as Alpha Ursae Minoris.
“North Star” is a title rather than the permanent name of one star. Earth’s rotation axis slowly changes direction over thousands of years, so different stars become the best markers of the North Celestial Pole at different times.
What is the North Star called?
The current North Star is called Polaris. The name comes from the Neo-Latin phrase stella polaris, meaning “pole star.” Its Bayer designation is Alpha Ursae Minoris (α UMi). Other traditional names associated with Polaris include the Pole Star and Lodestar, reflecting its long-standing importance as a guide in the northern sky.
What constellation is the North Star in?
Polaris is part of the constellation Ursa Minor, or the Little Bear. It marks the end of the Little Dipper’s handle and the tip of the Little Bear’s tail.
Learn more about Ursa Minor and other constellations that stay above the horizon throughout the year in our guide to circumpolar constellations.
Is Sirius the North Star?
No. Sirius is a completely different star in the constellation Canis Major, the Great Dog. With an apparent magnitude of −1.4, Sirius is the brightest star in the night sky. Polaris has an apparent magnitude of about 2.0 and ranks only around 50th in brightness.
Learn more about Sirius and the Canis Major constellation in our dedicated articles.
When can you see Polaris?
From most of the Northern Hemisphere, Polaris is circumpolar: it stays above the horizon all night and is visible throughout the year. It is fairly easy to see with the naked eye under a clear sky.
The farther north you are, the higher Polaris appears. Near the equator, it skims the northern horizon and may be hidden by haze, buildings, or terrain. From most of the Southern Hemisphere, Polaris remains below the horizon.
How to find the North Star
Polaris is not exceptionally bright, so it may not immediately stand out in a light-polluted sky. The easiest ways to identify it are to use the Big Dipper or a stargazing app.
How to find the North Star using the Big Dipper
The Big Dipper is a prominent star pattern within the constellation Ursa Major. Find Merak and Dubhe, the two stars forming the outer edge of the Dipper’s bowl. They are often called the Pointer Stars because they lead toward Polaris.
Draw an imaginary line from Merak through Dubhe and extend it about five times the distance between the two stars. You will reach Polaris, the brightest star near the end of the line and the last star in the Little Dipper’s handle.
The Big Dipper changes orientation as it circles the northern sky, so it may look upright, sideways, or upside down depending on the season and time of night.
Use our 15 Stars Everyone Can Find infographic to learn how to locate Polaris and other famous stars using familiar patterns in the sky.
How to find Polaris with Sky Tonight
The easiest way to find Polaris is with the Sky Tonight app:
- Launch the app and tap the magnifying-glass icon.
- Type “Polaris” in the search field and tap the matching result.
- Tap the blue target button to show Polaris on the sky map.
- Tap the compass button or point your device at the sky.
- Follow the on-screen arrow until you locate Polaris.
Because Sky Tonight uses your location and the current time, it can show you where to look even when trees, buildings, or light pollution make the usual star patterns difficult to recognize.
Why does Polaris appear fixed in the sky?
As Earth rotates, the sky appears to turn around the North Celestial Pole. Stars far from the pole travel in large arcs, while Polaris, only about 0.6° away in the mid-2020s, traces a circle roughly 1.2° across.
That is why Polaris looks almost fixed while other familiar stars appear to move around it. The key is Polaris’s position near the extension of Earth’s rotation axis, which makes its apparent daily motion very small.
Polaris is not completely motionless: its movement can be captured in long-exposure photographs, and its position relative to the North Celestial Pole changes gradually over centuries.
How to use Polaris for navigation
How to find true north with Polaris
For everyday orientation, Polaris indicates the approximate direction of true north, also called geographic north. Once you have identified the star, face it:
- North is in front of you.
- East is to your right.
- West is to your left.
- South is behind you.
Polaris is not exactly at the North Celestial Pole, so it can appear slightly east or west of true north. This difference is unimportant for casual orientation but must be corrected in precise celestial navigation.
Polaris or a compass: which is better for finding north?
Polaris and a compass solve slightly different problems. Polaris indicates approximate true north and is not affected by local magnetic fields, but it requires a clear night and a view of the northern sky.
A compass works in daylight and under clouds, but it points toward magnetic north — the direction of Earth’s magnetic pole. To determine true north, you may need to adjust the compass reading by the magnetic declination — the angle between magnetic north and true north at your location. You can check the magnetic declination for your location using an online calculator.
Neither method is universally better. For accurate navigation, use the appropriate corrections and more than one reference whenever possible.
How to estimate your latitude using Polaris
Polaris can help you estimate your northern latitude because its altitude above the horizon is approximately equal to your latitude.
At 45°N, for example, Polaris appears about 45° above the northern horizon — approximately four and a half fists at arm’s length. At the North Pole, it is almost overhead. Near the equator, it skims the horizon, where haze, terrain, buildings, and atmospheric refraction make it difficult to use.
To try this method, face north and find Polaris. Hold one arm straight out and place the bottom of your closed fist on the northern horizon. Stack your fists upward until you reach Polaris. One fist at arm’s length covers about 10° of sky, while the width of your little finger covers about 1°. Add the angles to estimate the star’s altitude and, therefore, your latitude. See our guide to measuring angular distances in the sky for more hand-measuring techniques.
Is Polaris a single star?
No. What looks like one star to the naked eye is a triple system consisting of Polaris Aa, Polaris Ab, and Polaris B.
- Polaris Aa is the bright supergiant and classical Cepheid variable that we see as the North Star.
- Polaris Ab is a much fainter F-type main-sequence star that orbits Polaris Aa roughly once every 30 years. It is far too close and faint for an ordinary amateur telescope.
- Polaris B is a wider F-type companion about 18 arcseconds away. Under steady skies, it can be separated with a modest telescope, although the glare from Polaris Aa makes the observation challenging.
NASA’s Hubble Space Telescope directly imaged the close companion Polaris Ab. Following the companions’ motion allows astronomers to measure the mass of Polaris Aa without relying only on theoretical stellar models.
What color is Polaris?
Polaris Aa is an F8 Ib yellow-white supergiant. To most observers, however, it looks white because its yellow tint is very subtle.
Its two companions are also F-type stars with broadly white or yellow-white colors, but they are too faint to affect the system’s naked-eye appearance noticeably.
Explore the colors, locations, and properties of other famous stars in our brightest stars infographic.
Why does Polaris change brightness?
Polaris Aa is a low-amplitude classical Cepheid variable. It repeatedly expands and contracts, causing its temperature, radius, and brightness to change over a cycle of about 3.97 days.
The variations are too small to notice casually with the unaided eye, but astronomers can measure them precisely.
Cepheids are crucial to astronomy because their pulsation periods are related to their true luminosities. By comparing a Cepheid’s true luminosity with how bright it appears from Earth, astronomers can estimate its distance. Polaris is the nearest and brightest classical Cepheid, making it an important laboratory for understanding these stars.
What have astronomers recently discovered about Polaris?
Modern instruments have revealed that this familiar navigational star is more complex than it appears.
2024: More precise measurements of Polaris’s mass, radius, and orbit
A 2024 study using the CHARA Array combined high-resolution observations of Polaris Ab with decades of radial-velocity measurements. The researchers calculated a dynamical mass of 5.13 ± 0.28 solar masses for Polaris Aa.
The same work measured a mean radius of 46.27 ± 0.42 solar radii, equivalent to about 32 million km, and refined the orbit of Polaris Ab. It also showed that Polaris is more luminous than some stellar-evolution models predict for a star of its measured mass.
2026: The first direct rotation-period measurement for a classical Cepheid
A study published in June 2026 used five years of magnetic monitoring to measure Polaris’s rotation period directly: 100.29 ± 0.19 days.
According to the researchers, this was the first direct rotation-period measurement for a classical Cepheid. Polaris’s weak, complex magnetic field remained remarkably stable throughout the observations, although its origin is still uncertain.
The measurements also indicate a high likelihood that the star’s rotation axis and the orbit of its close companion are strongly misaligned. This result may help astronomers investigate Polaris’s unusual evolutionary history.
Has Polaris always been the North Star?
No. Earth’s rotation axis slowly changes direction in a motion called axial precession, completing a cycle in roughly 26,000 years. As a result, the North Celestial Pole gradually moves against the background stars.
Around 2800 BC, the pole was much closer to Thuban in Draco. Later, Kochab in Ursa Minor served as a useful northern guide. Polaris gradually became the best bright marker of the pole; there was no single date when the title officially changed hands.
When will Polaris be closest to true north?
Polaris is still moving closer to the North Celestial Pole and will come within about 0.45° of it around the year 2100. After that, axial precession will carry the pole away from Polaris.
An exact date for the closest approach depends on how the calculation accounts for precession, nutation, aberration, and the star’s proper motion. Therefore, any specific day is only an estimate based on the chosen model, not a fixed astronomical milestone.
What is the next North Star?
As the North Celestial Pole moves through the sky, several bright stars will become useful northern markers. The dates are approximate, and not all of these stars will lie as close to the pole as Polaris does today:
- Gamma Cephei (Errai) will be the next prominent pole star, passing closest to the pole around the year 4100.
- Alderamin in Cepheus will become a useful northern marker around the year 7500.
- Vega will lie near the northern pole around the year 14,000, but it will remain several degrees away.
The precession cycle repeats in roughly 26,000 years, but the sky will not return to exactly the same pattern because stars also move through space.
North Star: Frequently Asked Questions
What is Polaris?
Polaris is Alpha Ursae Minoris, a triple-star system whose bright main component is the nearest classical Cepheid variable. It is currently the most useful naked-eye marker of the North Celestial Pole.
What constellation contains the North Star?
Polaris is in Ursa Minor, at the tip of the Little Bear’s tail. It also marks the end of the Little Dipper’s handle.
Is the North Star part of the Big Dipper?
No. Polaris is part of the Little Dipper, an asterism within Ursa Minor. The Pointer Stars Merak and Dubhe in the Big Dipper help lead observers toward it.
Is the North Star the brightest star?
No. Polaris is the brightest star in Ursa Minor, but it is only around the 50th brightest star in the night sky. Sirius is the brightest of all.
Does Polaris always point north?
In the mid-2020s, Polaris lies about 0.6° from the North Celestial Pole, so its bearing is close enough to true north for casual orientation. Its exact azimuth shifts slightly east and west of north, and precise navigation requires a correction.
Can you see Polaris from the equator?
At the equator, the North Celestial Pole lies on the horizon, so Polaris moves slightly above and below the horizon during each sidereal day. With a perfectly open northern horizon, it may be visible at favorable moments, but haze and atmospheric extinction usually make the observation difficult.
Can you see Polaris from the Southern Hemisphere?
From most locations south of the equator, Polaris remains below the horizon. From places just south of the equator, it may rise slightly above the horizon at certain times, but it stays extremely low and is usually difficult to observe.
Is there a South Star?
There is currently no bright star close enough to the South Celestial Pole to serve as an obvious southern equivalent of Polaris. Southern observers often use Crux, the Southern Cross, to estimate the direction of south.
How far away is Polaris?
Polaris is about 447 light-years from Earth. This means its light takes roughly 447 years to reach us, so when we look at Polaris today, we see it as it appeared in the late 16th century.
Polaris, the North Star: Bottom line
Polaris is not the brightest star, but its position less than 1° from the North Celestial Pole makes it one of the most useful guides in the Northern Hemisphere’s night sky. Polaris is also a remarkable triple system and the nearest classical Cepheid.
Use Merak and Dubhe in the Big Dipper to locate Polaris in the sky. For a quicker and easier method, use the Sky Tonight app to see exactly where the star appears from your location. Once you have found Polaris, you can measure its altitude above the horizon to estimate your latitude.
