'Instrumentum eiusdem ut altitudibus', from Tycho Brahe's 'Astronomiae Instauratae Mechanicae' (1602). Considered to be the greatest pre-telescope observer, Brahe's (1546-1601) contributions to astronomy were enormous. Not only did he revolutionise astronomical instrumentation, by emphasising the importance of accuracy for the first time, but also profoundly changed observational practice. He was the first to observe the obrits of the moon and planets, and the first to make corrections for atmospheric refraction.
© Science Museum / Science & Society Picture Library