Bye, Bye, Birdie #6

A Star to Steer Her By.

When we think of celestial navigation, we imagine the master of an old sailing ship taking sights of the stars with a sextant, chronometer, wearing a pointy hat. To us it seems an arcane art of a bygone era, best not spoken of in polite company.

In this installment of “Bye, Bye Birdie”, we’ll be talking about the much older art of literally steering by the stars, both as a means of checking our compasses and as simple aids to navigation, like lighthouse beacons burning steadfastly above us, whether in open ocean or urban harbors.

We don’t need to be veteran stargazers to utilize the sky in this way. From just three easily identifiable constellations, we can find our way anywhere in this world. I’ll present three ways of using the stars for guiding our vessels, requiring no special equipment or degrees in astronomy.

One of the most important uses of celestial bodies in modern navigation is the ability to externally verify our compasses (magnetic and electronic) when land is out of sight. With the aforementioned ephemerides (a table giving the coordinates of celestial bodies) and some math, we can use any celestial object for navigation at any time. However, there are a few cases that require no tools, tables, or math. These instances fortuitously rely on two of the best known and easiest to find constellations in the sky—The Big Dipper and Orion.