The Big Dipper, a prominent asterism in the northern sky, serves as a guidepost to locate the less conspicuous Little Dipper. The two outer stars in the Big Dipper’s bowl, known as the Pointers, point directly to Polaris, the North Star. Polaris marks the end of the handle of the Little Dipper, making it the key to finding this fainter star pattern.
Using the Big Dipper to Find the Little Dipper
Locating the Big Dipper is relatively easy due to its distinctive shape and bright stars. It appears high in the northern sky on spring evenings. Once you’ve found the Big Dipper, draw an imaginary line through the two Pointer stars at the outer edge of the bowl. Extend this line approximately five times the distance between the Pointers. This line will lead you directly to Polaris.
Polaris, while not exceptionally bright, stands out as the only prominent star in this area of the sky. Since Polaris sits at the tip of the Little Dipper’s handle, finding it unlocks the location of the entire asterism. The Little Dipper, also known as Ursa Minor, resembles a smaller, fainter version of the Big Dipper, with its bowl facing in the opposite direction.
Why is the Little Dipper Harder to See?
The Little Dipper’s stars are significantly fainter than those of the Big Dipper, making it challenging to spot, especially in areas with light pollution. A dark sky location, away from city lights, significantly improves the chances of seeing the Little Dipper.
Beyond the Dippers: Polaris and the Celestial Pole
Polaris holds a special significance as the North Star. Earth’s axis points almost directly towards Polaris, causing the entire northern sky to appear to rotate around it. While currently slightly offset from the true north celestial pole, Polaris will be at its closest alignment in the year 2102.
Interestingly, Polaris hasn’t always been the North Star. Due to a phenomenon called precession, Earth’s axis wobbles over a cycle of 26,000 years, causing different stars to take on the role of the North Star over time. Kochab and Pherkad, two stars in the Little Dipper’s bowl, were once twin pole stars thousands of years ago.
Dippers vs. Constellations: Asterisms Explained
It’s important to note that both the Big and Little Dippers are not constellations but asterisms. Asterisms are recognizable patterns of stars that are not officially recognized as constellations. The Big Dipper is part of the Ursa Major (Great Bear) constellation, while the Little Dipper belongs to Ursa Minor (Little Bear).
Finding the Little Dipper: A Summary
The Big Dipper acts as a celestial compass, guiding observers to the Little Dipper. By following the Pointers to Polaris, located at the end of the Little Dipper’s handle, you can successfully locate this fainter, but equally important, asterism. Remember to seek out dark skies for optimal viewing. No matter the Big Dipper’s position in the sky, the Pointer stars consistently direct you towards the North Star and the Little Dipper.
