JOHANN KEPLER, Ad Vitellionem paralipomena ..., Frankfurt, 1604
Biblioteca Nazionale Centrale di Firenze, Magliab. 15.3.211
Facsimile

This work deals essentially with how to determine the magnitude of eclipses of the Sun and the Moon. The only optical instrument discussed by Kepler is the human eye, whose structure is essential to him for formulating a new theory of visual perception.