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Celestial Cartography

          Have you ever wondered where astronomical objects were in space? Interesting enough, there’s actually a profession for people who specialize in this certain field! Celestial cartography is an area of astronomy-related to producing maps of the stars. Similar to the use of a regular map, a star map is divided into a grid to make the tracking easier. While tourists use maps to help them get from location to location, astronomers use star maps to help them identify and locate many different celestial bodies such as stars, nebulae, and galaxies.

          Throughout history, humans have tried to better understand the placements of astronomical objects in space. The oldest attempts to map stars were dated to around 2000BCE in Babylon on boundary stones. On them, many constellations we can still find in the night sky today were marked which included Orion, Leo, and Scorpius. However, an underlying issue in mapping these celestial bodies was accuracy. When astronomers would map their findings, they had to make sure that where they drew it matched up with where it would actually be in space. Additionally, because of a great lack of information transfer at the time, astronomers had to know the stars in the sky before drawing the stars as they would inform each other of specific stars through phrases like “the western star of the two in the forehead” or “the star at the tip of the muzzle”. With time, astronomers were able to record the position of the stars using ecliptic coordinates. The ecliptic is a guide that helps one understand the starting point for a celestial coordinate system. It is an imaginary line on the sky that projects the annual path of the sun. By using this imaginary line, every star, nebula, and galaxy can be easily pinpointed and drawn into a star map.

          The earliest recorded work of celestial cartography was written by Ptolemy, a famous Egyptian mathematician, astronomer, and geographer born in the 100(’s) AD, called Almagest. This book contained 48 constellations, almost all of which can still be seen in the night sky today. With the devices of his time, he was able to measure 1022 stars with great accuracy. To classify the star’s brightnesses, Ptolemy created a scale of one to six where one was the brightest of the stars and six classified the ones barely visible to the naked eye.

Sources: “Celestial Cartography.” Lumen, 


Tirion, Wil. “The History of Uranography, or Celestial Cartography.” Popular Astronomy, 8 July 2018, 

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