One of the first star groups that children learn to find is the Big Dipper Constellation. It instills young astronomers with a sense of awe at the wonders the sky holds. And many adults remember warm summer nights lying on a blanket in the backyard while stargazing.
In our house, we got our groupings wrong as often as not, which sometimes led to sibling tussles trying to prove who was right. But searching the sky for the Big Dipper Constellation was, and still is, a highlight for celestial observations.
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What Are Asterisms?
The International Astronomical Union (IAU) recognizes 88-star groups as constellations. Technically, they are the sky’s regions orderly divided to help identify specific locations of the celestial objects.
As international communication and relations grew, the IAU understood the necessity of systematically identifying celestial regions. Since most countries had their own names for celestial objects, the need for internationally recognized features grew more apparent.
And familiar star patterns beyond the constellations gained the name asterisms. These are smaller, recognizable groupings within the more prominent constellations.
Is the Big Dipper Constellation Actually an Asterism?
The Bigger Dipper Constellation is actually an asterism within the Ursa Major (Great Bear) Constellation. In fact, the asterism’s long ladle handle represents the Great Bear’s long tail, even though bears truly have short bushy tails.
But its technical classification doesn’t keep the Big Deeper from capturing Earth’s attention.
Big Dipper In Detail
The Big Dipper Constellation contains seven bright stars. One is a Megrez of third magnitude (δ), and the other six are second-magnitude stars. This grouping is perhaps the most recognizable asterism in the Northern Hemisphere. And its ladle-shaped configuration contains stars as close as 68 light-years from Earth and as far as 631 light-years.
Viewing the Big Dipper Constellation From Space
The JunoCam onboard NASA’s Juno Spacecraft captured some of the first images of the Big Dipper Constellation from space. The solar-powered spacecraft launched in 2011, and scientists used the asterism as a way to ensure the camera worked correctly as it made its way to Jupiter.
Juno took the test cam images once it passed Mars, so they are indeed the furthest space images of the Big Dipper.
The Big Dipper’s Other Names
Humans have looked towards the Big Dipper for eons, which we call by many different names. Here are some of them.
- The Big Dipper (North America)
- Plow or Plough (United Kingdom and Ireland)
- The Great Cart or Wagon “Großer Wagen” (Germany)
- Seven Ploughs (Malaysia)
- Seven Oxen (Latin)
- Beidou “Northern Dipper” (China)
- Sao Bánh lái lớn “The Big Rudder Stars” (Vietnam)
- Saptarishi “Seven Sages” (India)
No matter what you call the Big Dipper Constellation, there’s no doubt of its influence on humans throughout history.
The Big Dipper Constellation Through American History
America’s love affair with the Big Dipper Constellation dates back to 1400 B.C.E. when young Native American men proved their strength and maturity by correctly locating the asterism. Elders taught young people to navigate by the stars, knowing that finding it meant they had vital eyesight for hunting or tribal defense.
Later in our country’s history, the Big Dipper guided runaway enslaved people to their freedom on the Underground Railroad. The Big Dipper points through the sky toward the North Star, so escapees knew to follow it to the Northern States for a free life. Although accounts differ, the folksong, Follow the Drinking Gourd, might be part of the infamous march North.
The Big Dipper Constellation on the Alaskan Flag
The American Legion sponsored a flag design contest in the 1920s for the Alaskan territory. Middle schooler Benny Benson won the competition with his blue background containing the North Star and the Big Dipper.
Benson chose the deep blue of the Alaskan skies and its state flower, the forget-me-not. And the eight gold stars show Alaska’s position close to the heavens. After winning the contest, the Alaskan legislature approved Benson’s design. And it remained in place after the territory’s statehood pronouncement in 1959.
What Time Of Year Is Best To Observe The Big Dipper?
Springtime in the Northern Hemisphere is the best time to view the Big Dipper. Look for Ursa Major’s brightest stars to find the Big Dipper’s long handle and scoop.
The Big Dipper’s Future Shape
The stars within the Big Dipper Constellation continually move apart from one another. So scientists believe that in 100,000 years, the asterism will look less like a ladle and more like a shoe.
The Big Dipper’s Role In The Sky
Travelers throughout human history look to the sky for guidance. And they find it in the Big Dipper Constellation.
The Big Dipper As A Sky Compass
The “pointer stars” near the end of the Dipper’s bowl point to the North Star, Polaris. Merak and Dubhe act as a compass for travelers on land and sea.
To get your bearing, find Merak and then stretch your eye from it through Dubhe (at the top of the scoop or bowl) and then continue in a straight line to Polaris. It is about five times the distance between the two pointers.
Once you find Polaris, you are pointing due North. So you’ll know South is behind you, with West on your left and East on your right. And there you have one of humanity’s first compasses.
The Big Dipper As A Sky Clock
You can even use the Big Dipper Constellation as a giant sky clock since Ursa Major circles the pole once per 24 hours. The Earth’s rotation makes this apparent motion fairly accurate for telling the time at night.
Connect an imaginary line from the pointer stars to Polaris as the hour hand. Then practice over multiple nights of sky viewing to see how close you can estimate the actual clock time. It will undoubtedly take practice, especially since the constellation travels counter-clockwise around Earth’s North Pole. But you can get a close approximation of time using the Big Dipper as a clock.
The Big Dipper Constellation As A Sky Calendar
Since you can use the Big Dipper as a clock, it only makes sense that it also changes throughout the year, making it a useful calendar. Seasons are easier to detect than individual months, but even that is possible for experienced stargazers.
- Spring: The Big Dipper soars high above the northern horizon and stretches almost directly overhead to a point called the zenith.
- Summer: The Big Dipper turns 90 degrees counterclockwise. The bowl points down and lies west of the North Pole in the early evening.
- Fall: Like the Great Bear’s hibernation preparation, the Big Dipper Constellation skims the northern horizon way beneath Polaris. It’s like bears moving towards a cave for the winter.
- Winter: The Big Dipper starts climbing higher in the night sky until it almost stands on its handle in the evening.
The Big Dipper Constellation Wrap Up
The Big Dipper Constellation doesn’t actually qualify as a constellation at all, even though most of us call it that. Instead, it is an asterism, a recognized star grouping within a larger constellation of stars.
The Big Dipper captures children’s imaginations and continues awing adults with its prominence in the night sky. Throughout history, humans use the asterism to guide our paths and help us tell time. It acts as a compass, a calendar, and even a pathway to freedom.
As one of the most recognized star patterns, the Big Dipper has a special place in the heavens and our hearts.