When was Polaris first discovered as the North Star?

Has Polaris always been known as the North Star?

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Polaris is the northern hemisphere’s Pole Star – all of the stars in the northern sky appear to circle it. Image Credit: Ted Quackenbush

Polaris is the northern hemisphere’s Pole Star – all of the stars in the northern sky appear to circle it. Image Credit: Ted Quackenbush

Asked by Anna Weston

Polaris was first catalogued in 169 AD by Claudius Ptolemy. However it was not used as a navigation tool until at least the 5th Century when the Macedonian writer and historian Stobaeus described it as ‘always visible’.

The interesting thing was that Polaris was not always the Pole Star, nor will it always be. The ‘wobble’ of the Earth’s axis, also known as precession, means that over time the star the North Pole points to will change. In fact, it was not until around the 12th Century that Polaris could be reasonably used as the Pole Star. And by the year 4000, the precession effect means that we will have a new Pole Star – Gamma Cephei.

Answered by Sophie Allan from the National Space Centre

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