The entire northern
sky wheels around Polaris. Some assume its the brightest star
in the sky. In fact, Polaris ranks only 50th in brightness.
The North Star or Pole Star aka Polaris is famous
for holding nearly still in our sky while the entire northern sky
moves around it. Thats because its located nearly at
the north celestial pole, the point around which the entire northern
sky turns. Polaris marks the way due north. As you face Polaris
and stretch your arms sideways, your right hand points due east,
and your left hand points due west. About-face of Polaris steers
you due south. Polaris is not the brightest star in the nighttime
sky, as is commonly believed. Its only about 50th brightest.
But you can find it easily, and, once you do, youll see it
shining in the northern sky every night, from N. Hemisphere locations.
Follow the links below to learn more about Polaris.
marks the end of the Handle of the Little Dipper. Chart for
early autumn evening Image via EarthSky
How to see Polaris. This star is bright
enough to spot even from some suburban skies. In a dark country
sky, even when the full moon obscures a good deal of the starry
heavens, the North Star is relatively easy to see.
That fact has made this star a boon to travelers throughout
the Northern Hemisphere, both over land and sea. Finding Polaris
means you know the direction north.
Best of all, Polaris is readily found by using the prominent
group of stars known as the Big Dipper, called the Plough in the
UK, which may be the Northern Hemispheres most famous star
To locate Polaris, all you have to do is to find the Big Dipper
pointer stars Dubhe and Merak. These two stars outline the outer
part of the Big Dippers bowl. Simply draw a line from Merak
through Dubhe, and go about 5 times the Merak/Dubhe distance to
The Big Dipper, like a great big hour hand, goes full circle
around Polaris in one day. More specifically, the Big Dipper circles
Polaris in a counter-clockwise direction in 23 hours and 56 minutes.
Although the Big Dipper travels around Polaris all night long, the
Big Dipper pointer stars always point to Polaris on any day of the
year, and at any time of the night. Polaris marks the center of
Natures grandest celestial clock!
By the way, Polaris is famous for more reasons than one. Its
famous for hardly moving while the other stars wheel around it.
And its famous for marking the end of the Little Dippers
handle. The Little Dipper is tougher to spot in the night sky than
the Big Dipper. But if you use the Big Dippers pointer stars
to locate Polaris, youll be one step closer to seeing the
As you travel northward, Polaris climbs higher in the sky. If
you go as far north as the North Pole, youll see Polaris directly
overhead. As you travel south, Polaris drops closer to the northern
horizon. If you get as far as the equator, Polaris sinks to the
horizon. South of the equator, Polaris drops out of the sky.
you take a time exposure photograph of the northern sky (or,
in this case, the northeast), you see all the stars are moving
around Polaris, which is on the left in this image. This image
by Taro Yamamoto via an article on long exposure star trail
History of Polaris. Polaris hasnt
always been the North Star and wont remain the North Star
forever. For example, a famous star called Thuban, in the constellation
Draco the Dragon, was the North Star when the Egyptians built the
But our present Polaris is a good North Star because its
the skys 50th brightest star. So its noticeable in the
sky. It served well as the North Star, for example, when the Europeans
first sailed across the Atlantic over five centuries ago.
And Polaris will continue its reign as the North Star for many
centuries to come. It will align most closely with the north celestial
pole the point in the sky directly above Earths north
rotational axis on March 24, 2100. The computational wizard
Jean Meeus figures Polaris will be 2709 (0.4525o) from
the north celestial pole at that time (a little less than the angular
diameter of the moon when at its farthest from Earth).
Meanwhile, there is no visible star marking the celestial pole
in the Southern Hemisphere. Whats more, the Southern Hemisphere
wont see a pole star appreciably close to the south celestial
pole for another 2,000 years.
At one time in human history, people literally depended on their
lucky stars for their lives and livelihood. Luckily, they could
trust the Big Dipper and the North Star to guide them. People could
sail the seas and cross the trackless deserts without getting lost.
When slavery existed in the United States, slaves counted on the
Big Dipper (which they called the Drinking Gourd) to show them the
North Star, lighting their way to the free states and Canada.
While being honored as the North Star, Polaris enjoys the title
of Lodestar and Cynosure as well.
artists illustration of Polaris and its two known companion
stars via the Hubble News Center.
Polaris science. The single point of light
that we see as Polaris is actually a triple star system, or three
stars orbiting a common center of mass. The primary star, Polaris
A, is a supergiant with about six times the mass of our sun. A close
companion, Polaris Ab, orbits 2 billion miles from Polaris. Much
farther away, near the top of the illustration at right, is the
third companion Polaris B. Polaris B is located approximately 240
billion miles from Polaris A. The two companion stars are the same
temperature as Polaris A, but are dwarf stars.
Astronomers estimate Polaris distance at 430 light-years.
Considering the distance, Polaris must be a respectably luminous
star. According to the star aficianado, Jim Kaler, Polaris is a
yellow supergiant star shining with the luminosity of 2500 suns.
Polaris is also the closest and brightest Cepheid variable star
a type of star that astronomers use to figure distances to
star clusters and galaxies.
Polaris position is RA: 2h 31m 48.7s, dec: +89° 15'