The night skies have long held a fascination for Man. Every glimpse should see the sky studded with up to seven or eight thousand stars. However, stargazers find that with the current levels of light pollution from cities around the world, so many stars are blotted out that it takes a great leap of the imagination to identify the constellations. Now the only way to clearly see the beauty of the heavens is with a Constellation Map that accurately charts every single star of the skies at any specific time or place in either the Northern or Southern Hemispheres.
In centuries past, tracking the stars was a vital part of every day life, creating a calendar, marking the seasons for planting crops, and for navigating across the seas. Claudius Ptolemy (100-170AD) of Alexandria in Ancient Egypt, was the earliest astronomer to realize that locating individual stars was much easier if they were bound together by imaginary lines to form shapes that became known as constellations. Many of the thirty-six constellations that can be seen drifting above the Northern Hemisphere are credited to Ptolemy, for instance, Cygnus the Swan or Corona Borealis meaning the Borthern Crown. Some names recall the mythological heroes of Ancient Greece such as Perseus or the winged horse, Pegasus. Thousands of years ago, the constellation of Draco the Dragon, was the key to locating the Celestial Pole, the gateway to eternal life. Today, Draco provides the location of the Draconids, the spectacular shower of meteorites that flash across the night sky every October.
Navigating The High Seas
Sailors relied on the positions of the stars to navigate and the outlines of constellations helped them locate them swiftly. As the great 16th Century voyages of Ferdinand Magellan and Sir Francis Drake began to open up sea routes around the globe, the night skies of the Southern Hemisphere were found to be noticeably different. Another fifty-two constellations would eventually be created to help travellers find their way. While navigators in the north watch for Polaris to determine their exact position, those in the Southern Hemisphere use Crux, the Southern Cross.
The Dutch navigator, Pieter Dirkszoon Keyser (1590-1596), assisted by Frederick de Houtman, sailed extensively in Indonesia to chart the stars of the Southern Hemisphere. Many of the constellations they created were named after some of the exotic creatures they had seen on their travels, such as Volans the Flying Fish, Tucana the Toucan and the Chamaeleon. In 1641,the Polish mathematician and astronomer, Johannes Hevelius (1611-1687), using the largest tubed telescope of the era, created more constellations including Scutum the Shield and Vulpecula the Fox in 1690. Later additions came from the French cartographer and astronomer, Nicolas-Louis de Lacaille (1713-1762). He journeyed to the Cape of Good Hope in South Africa with the intention of using trigonometry to calculate the distances and sizes of the planets. However, his first task was to catalogue more than ten thousand stars, creating fourteen new constellations, including Mensa or Table Mountain and the Sculptor, in the process.
In 1693, the astronomer, Johannes Bayer began cataloguing the stars according to how bright they appeared to be, a classification method known as Visual or Apparent Magnitude. He gave them letters of the Greek alphabet, labelling, for instance, the brightest star in the constellation of Taurus as Alpha Turi, the next brightest, Beta Turi and so on. Unfortunately, 17th Century technology prevented him assessing the stars with the greatest accuracy, so many of the listings are not necessarily in the correct order. Modern day Constellation Maps follow the finalized catalogue from 1922, authorized by the International Astronomical Union and can chart all the stars that are overhead from anywhere in the world at any time, even in daylight, a feat which would have amazed Bayer and his fellow astronomers.