“I am as constant as the northern star – of whose true-fixed and resting quality – there is no fellow in the firmament.” (Shakespeare – Julius Caesar III i 65)
Polaris. The North Star. Probably the most important celestial guidepost in the galaxy (at least if you’re on earth). As mentioned on July 26, 2011, I taught astronomy merit badge at Camp Napowan – a Boy Scout camp in Wild Rose, WI. For late night “star hikes,” the first point of interest – and discussion – was always Polaris.
Why Polaris? First – it never moves. Day or night – winter or summer – when you are in the Northern Hemisphere – Polaris will always be in the same spot. Every star and galaxy revolves around Polaris (at least from our perspective here on earth). Second, the degree of altitude above the horizon gives you near perfect north latitude. Chicago is 42 degrees north latitude. Polaris is 42 degrees above the horizon. Fort Worth is 33 degrees north latitude. Polaris is 33 degrees above the horizon. And so on. Finally, when you draw a straight line from Polaris to the ground, you have true North. True North varies from magnetic North by a few miles to a few degrees depending on where you are. This variance is called “declination.”
To find Polaris – one need only find the Big Dipper (Ursa Major). Go to the two vertical stars at the far end of the dipper and draw a straight line up. Five times the distance between those stars (Merak and Dubhe). Polaris (a bright 2d magnitude star) is the tail star of the Little Dipper (Ursa Minor).
Polaris sits 433 light years from earth. It is a “double star” (or “multiple” star) consisting of several stars which appear to be one. Just think – if you could transport yourself to Polaris and look back on earth with a powerful telescope, you would see the earth — as it was in the year 1584 . . . . .