February is the month we traditionally acknowledge Americans of African origin, and the plight of their ancestors held as slaves during the early years of our country. During the years leading up to and around the American Civil War, slaves very often made their way north to freedom by taking advantage of the Underground Railroad, a system of people and locations that were safe havens or safe routes for the escaping slaves to follow. Much of the travel was done at night and as was common in those days, people used their knowledge of the stars to help determine compass directions. Primarily used were the stars of the two dipper-shaped patterns known as the Big Dipper and the Little Dipper. These easily recognizable star patterns, or asterisms, are parts of the constellations Ursa Major, the Great Bear, and Ursa Minor, the Little Bear. The Big Dipper asterism was also known to many as the Drinking Gourd due to its resemblance to a common gourd that, when dried out, was used as a drinking vessel.

   Using a readily available rotating planisphere or the Big Dipper Star Clock pattern, one may explore the changing position of these stars due to the rotation and revolution of the Earth. Additionally, circumpolar stars may also be used as a sky clock for approximating the local time due to the regular rate that the Earth rotates. These stars and their associated constellation patterns never rise or set relative to the horizon, but are visible all night long. They follow an apparent counterclockwise circular pattern around a point in the sky known as the north celestial pole. In the Northern Hemisphere the north celestial pole is marked by the star we call the North Star, or Polaris. It is the end star in the handle of the Little Dipper, and is very close to being directly over the Earth’s North Pole. As the Earth rotates about its axis of rotation, the circumpolar stars appear to follow a circular motion around Polaris, neither rising nor setting.