Circumpolar Stars: Stars That Never Set

While most stars rise in the east and set in the west like the Sun, some stars never dip below the horizon at all. These are circumpolar stars, and they trace complete circles around the celestial pole every 24 hours without ever setting. They are visible every clear night of the year from your location, making them reliable companions for stargazers.

What Makes a Star Circumpolar?

Whether a star is circumpolar depends on two things: the star's declination (its angular distance from the celestial equator) and your latitude on Earth. A star is circumpolar if its declination is greater than 90 degrees minus your latitude.

For example, if you observe from 45 degrees north latitude, any star with a declination greater than +45 degrees (that is, 90 - 45) is circumpolar. It will circle around Polaris without ever touching the horizon.

The closer a star is to the celestial pole, the smaller the circle it traces. Polaris, less than a degree from the north celestial pole, barely moves at all. Stars farther from the pole trace larger circles, with the outermost circumpolar stars just skimming above the horizon at their lowest point.

Circumpolar Constellations from Mid-Northern Latitudes

From around 40-50 degrees north latitude (covering much of North America, Europe, and northern Asia), the following constellations are fully circumpolar:

Ursa Major (The Great Bear / Big Dipper)

The Big Dipper is the most recognized star pattern in the Northern Hemisphere. It is visible every night of the year, though its position rotates around Polaris -- sometimes high overhead, sometimes closer to the northern horizon. The pointer stars of the Big Dipper lead directly to Polaris, and the handle curves to Arcturus.

Ursa Minor (The Little Bear / Little Dipper)

Ursa Minor contains Polaris at the tip of its handle. The Little Dipper is fainter than its bigger counterpart, with most of its stars requiring at least suburban darkness to see clearly.

Cassiopeia

The W-shaped (or M-shaped, depending on orientation) constellation is always visible and sits opposite the Big Dipper across Polaris. When the Big Dipper is low, Cassiopeia is high, and vice versa. It lies within a rich section of the Milky Way.

Cepheus

A house-shaped constellation between Cassiopeia and the pole. Cepheus contains the famous variable star Delta Cephei, the prototype of an important class of pulsating stars used to measure cosmic distances.

Draco (The Dragon)

A long, winding constellation that curls between the two Dippers. Draco's head is a compact quadrilateral of stars near Vega. The dragon's body loops around Ursa Minor.

How Latitude Changes the Circumpolar Sky

Your latitude dramatically affects how much of the sky is circumpolar:

• At the equator (0 degrees): No stars are circumpolar. Every star rises and sets.
• At 30 degrees latitude: Stars within 30 degrees of the pole are circumpolar. The Big Dipper partially dips below the horizon.
• At 45 degrees latitude: The main circumpolar constellations listed above are all visible year-round.
• At 60 degrees latitude: Many more constellations become circumpolar, including parts of Perseus and Auriga.
• At the North Pole (90 degrees): All visible stars are circumpolar. Nothing rises or sets -- every star circles at a fixed altitude.

The Counter-Circumpolar Stars

The opposite effect also exists. Stars near the opposite celestial pole are never visible from your location. From 45 degrees north, stars with declination below -45 degrees never rise above the horizon. This is why Northern Hemisphere observers cannot see the Southern Cross or the Magellanic Clouds without traveling south.

Watching the Sky Rotate

Circumpolar constellations are the best way to observe Earth's rotation in action. On a clear night, face north and note the position of the Big Dipper. Come back an hour later, and it will have rotated noticeably counterclockwise around Polaris. Over the course of a single long winter night, you can watch the entire rotation cycle play out. This rotation is also why the seasonal sky changes -- as the Big Dipper's position shifts through the hours, different constellations on the opposite side of the sky come into view.

Star Trails

Long-exposure photographs of the circumpolar region reveal star trails -- concentric arcs centered on Polaris. These images beautifully illustrate the sky's rotation. You can create star trail images by stacking many short exposures or by using a single very long exposure (which requires a dedicated camera rather than a phone).

Circumpolar Deep-Sky Objects

Several interesting deep-sky objects are circumpolar from mid-northern latitudes:

• M81 and M82: A galaxy pair in Ursa Major, visible through binoculars.
• M101 (Pinwheel Galaxy): A face-on spiral galaxy near the Big Dipper's handle.
• NGC 457 (Owl Cluster): A charming open cluster in Cassiopeia.
• NGC 7789 (Caroline's Rose): A rich open cluster in Cassiopeia.
• The Double Cluster (NGC 869/884): In Perseus (circumpolar from higher latitudes).

Common Questions

Is Polaris circumpolar?

Yes, from everywhere in the Northern Hemisphere. It is the most circumpolar star of all, sitting almost exactly at the north celestial pole.

Are there circumpolar constellations in the Southern Hemisphere?

Yes. The Southern Cross (Crux), Centaurus, and Carina are circumpolar from far-southern latitudes, circling the south celestial pole.

Why do circumpolar constellations appear in different positions each season?

They are always visible, but their orientation changes as they rotate around the pole. The Big Dipper is above Polaris in spring evenings and below it in autumn evenings.

Explore the Circumpolar Sky

Open StarGlobe to see which constellations are circumpolar from your latitude and watch how they rotate around the pole in real time. These dependable star patterns are your year-round guides to the night sky, always present regardless of the season or the time of night. For seasonal highlights, see our winter, spring, summer, and autumn sky guides.