Surprise! The Big Dipper Is an Asterism, Not a Constellation

By: Valerie Stimac  | 
Big Dipper
The Big Dipper asterism is made up of seven of the brightest stars in the night sky. Ad_hominemShutterstock

If there's one thing we can safely say about astronomy, it's that there's no end to what we can learn. Thanks to improved telescope technology and a greater understanding of what's going on in our solar system, we're always learning about new types of phenomena in the distant reaches of the universe and closer to home.

One thing that doesn't change much is the night sky above us: The stars that wheel overhead look much the same as they have for millennia, and humans have long used these stars for navigation, and told stories based on their shapes. Prominent in the northern sky, the Big Dipper, made of seven bright stars, is one such star grouping that has a storied history — and, it turns out, many names.


Whether you're brand new to astronomy or just keen to learn more about one of the most prominent groupings of stars in the sky, the Big Dipper is a great place to start. Even if you think you know everything about these Big Dipper stars, it always helps to go back to basics — you'll probably learn a thing or two.

The Big Dipper Is An Asterism in the Northern Night Sky

While you might think that the Big Dipper is a constellation, this is actually not the correct name for it; instead, the Big Dipper should be called an "asterism," which is a prominent pattern of stars in the sky.

Some asterisms are all within one constellation, such as Orion's Belt within the constellation Orion, whereas others are made up by stars in different constellations such as the Summer Triangle, which is comprised of Vega (in the constellation Lyra), Deneb (in Cygnus) and Altair (in Aquila).


In the case of the Big Dipper, it is located entirely within the constellation Ursa Major, or the Great Bear. This is a prominent constellation in the northern hemisphere — in fact, it is a circumpolar constellation, meaning it always circles around the north star, Polaris, which is bright, but not the brightest star in the heavens.

The Big Dipper Is An Ancient Constellation with Many Names

The Big Dipper has been named by people for as long as we've been looking skyward; nobody is credited with "discovering" or "naming" the Big Dipper. In fact, not everyone even calls it by that name.

While those of us in North America might call it the Big Dipper because it looks like a ladle with a handle, this is not the only name for such a prominent group of stars. In the United Kingdom, it's called the Plough, whereas the Germans call it the Großer Wagen or "Great Wagon." Romanians and many other Slavic language speakers also refer to it as the "Great Wagon" in their languages.


The seven stars of the Big Dipper are Dubhe, Merak, Phecda, Megrez, Alioth, Alkaid and Mizar.
Wikimedia Commons (CC BY SA 4.0)

To the Samí people of northern Scandinavia, it is referred to as Fávdnadávgi ("Fávdna's bow") or simply dávggát ("the bow"), referring to the great hunter Fávdna (the star Arcturus).

In early Chinese astronomy records, it is referred to as Beidou, or "northern dipper," whereas Filipino speakers might call it tabo, referring to the one-handled water pot used ubiquitously in Filipino households and bathrooms for purposes of personal hygiene.

All this to say, many people refer to it in a name that is both familiar to them because of its shape, or part of their cultural mythology — and this is where many of the constellations get their stories too.


How to Spot the Big Dipper

If you want to spot the Big Dipper, you'll need to be in the northern hemisphere — above the equator — and have a view of the northern sky; the further north you are, the higher the Big Dipper will appear once the sun goes down. All the stars of the Big Dipper are visible no matter what time of night or time of year, as long as you have a clear northern horizon.  

You'll want to look for four bright stars that make a near rectangle; these are the "bowl" of the dipper, and then you need to find the "handle."


Also keep in mind seasonality: astronomers use the phrase "spring up and fall down" to remember where to look for the Big Dipper. This is because the Big Dipper changes orientation throughout the year.

In the fall, the Big Dipper rests on the horizon in evening. In the winter, the handle appears to be dangling from the Big Dipper bowl. You will find the Big Dipper upside down in the spring and, in the summer, the bowl leans our pours out toward the ground.


Frequently Asked Questions

How does the appearance of the Big Dipper change throughout the year?
The appearance of the Big Dipper changes throughout the year due to Earth's orbit around the Sun. Its position in the sky shifts, making it appear at different heights and angles, depending on the season and time of night. In the Northern Hemisphere, it can be seen circling close to the North Star, Polaris, and remains visible throughout the year, changing its orientation but always pointing north.
What is the significance of the Big Dipper in navigation?
The Big Dipper has historically been significant in navigation, especially before the widespread use of the compass. Its two outer stars, Dubhe and Merak (the "pointer stars"), form a line that extends out to Polaris, the North Star. Since Polaris lies nearly in a direct line with the Earth's rotational axis, it remains almost stationary in the sky, providing a constant reference for north, aiding in nighttime navigation.