Andromeda and the Technological Revolution in Astronomy

Abstract

It is easy to overlook the impact that technology has had on astronomy. Until the invention of the telescope in the seventeenth century, astronomical study was done mostly with the naked eye. The universe was limited to what the visually unaided eye could see. This meant that the night sky consisted of the permanent stars to the sixth magnitude, the planets Mercury, Venus, Mars, Jupiter, and Saturn, the Moon, comets and meteors, and other occasional items such as supernovae. The universe seemed vast to the ancients, but it was clearly small, at least by contemporary standards of the universe, which can see objects to the 25th magnitude, back almost to the beginning of the universe 13.7 billions of years ago.