Star and Solar System Maps: A History of Celestial Cartography

Abstract

Abstract Since antiquity, people have observed the night sky. To establish order and predictability, people made maps of the heavens. Two kinds emerged. The first were star maps, organized into constellations but focused on stellar location in the sky. Stars were placed in a coordinate system, initially based on celestial latitude and longitude oriented to the ecliptic, but later based on decl. and R.A. oriented to the celestial equator. Over time, telescopic and scientific needs called for more detailed coordinate systems, and constellation images disappeared. The second kind of heavenly map depicted the solar system and focused on planetary locations and surface characteristics. For many centuries, these were cosmological diagrams with concentric planetary and stellar circles, centered first on the Earth and then the Sun. Now such maps have no stellar boundary, and ever larger telescopes and space probes allow us to view planetary surfaces in unprecedented detail.