Find Polaris and Never Get Lost Again! (At Night, That Is)

Do you know how to find the North Star, Polaris? It is not the brightest star in the nighttime sky, despite what many have been taught, but you can find it through city lights if you know where to look. 

Polaris as imaged by the Hubble Space Telescope. Image Credit: NASA/HST

It is important to know how to find Polaris, because if you do, you will never get lost at night (unless it is cloudy, maybe). This is because Polaris is almost exactly above the North Pole. As Earth rotates through its day, its axis points out the North Pole, towards Polaris. If you stayed up all night and watched the stars, you would see them rise in the east and set in the west. In the north, however, you would see the stars make a big circle. One star would barely move at all - Polaris.  It would seem like all the stars were rotating around this star, the North Star.
 

Image Credit: Kate Hoffman, local photographer. This image was taken near Kickapoo, IL. Kate took 180 exposures over 1.5 hours.

To find Polaris, you first need to find the Big Dipper (part of the constellation Ursa Major, the Big Bear). It is easy to spot in the spring, because it is high in the sky. It looks like it is dumping its water out on Earth below. Imagine a line drawn through the two stars at the end of the Dipper's cup; Merak and Dubhe. Follow this line down (at this time of year) to the next bright star you see, and you will have found the North Star. Polaris is in the handle of the Little Dipper, which is also the Little Bear, Ursa Minor. Try to find Polaris in the picture below, set for Peoria at 10 PM.

Image Credit: Stellarium. Click on the picture to see a larger image.

The same image with constellation lines below:

Image Credit: Stellarium. Click on the picture to see a larger image.

Image Credit: Wikipedia Commons

Polaris has been the North Star for about a thousand years, but other stars have been the pole star in the past. Because Earth wobbles on its axis over time (a motion called precession) the role of the pole star has passed from star to star over the eons.
 
In 3000 BCE, the pole star was a faint star named Thuban in the constellation of Draco the Dragon. Thuban is visible in dark skies, but difficult to spot. Astronomy was important to the ancient Egyptians, who used Thuban to align the sides of the pyrimids with the cardinal directions. See picture below.  

Image Credit: Stellarium. Click for larger image.

By 3000 CE the star Alrai in Cepheus the King will be closer to the north celestial pole than Polaris, and by 5200 CE the star Iota Cephei will be the next pole star. See circled star in the image below.

Image Credit: Stellarium. Click for larger image.

So go out in your backyard sometime and look for Polaris. It is always in the same spot, no matter the time or season! As always, if you are interested in learning more about the stars and constellations, visit the Dome at the Peoria Riverfront Museum, where we teach about space and science everyday. Find showtimes and descriptions here. And if you are interested in learning more about Ancient Egyptians, take in the Peoria Riverfront Museum's new Giant Screen Theater movie, Mummies: Secrets of the Pharaohs!