Astronomical Images : Proof that solar eclipses differ according to the relative distance of the Sun, Moon and Earth

Christophorus Clavius

Astronomical Images

<p style='text-align: justify;'>This is the third edition of Clavius's work, first published in Rome in 1570 and then in 1575. This text shows clearly how commentaries on Sacrobosco's <i>De sphaera</i> had become, by the end of the sixteenth century, substantial astronomical treatises in their own right. Clavius's work was used as an advanced astronomy textbook in Jesuit colleges throughout Europe. This edition contains an important innovation with respect to the previous ones. Here Clavius asserts the importance of astronomy and its methods against scholastic philosophers. He presents his views on Copernicanism. It is noteworthy that although the present edition appeared almost a decade after the 'Brahe' nova of 1572, here Clavius ignored the new phenomenon. In the 1585 edition he did introduce a section on it and a discussion of its location. This issue was a major point of contention with the scholastic philosophers, who maintained the incorruptibility of the heavens. The woodcut shows that solar eclipses differ according to the relative distances of the Sun, Moon and Earth. A is the Sun, B is the Moon, L the Earth. At times, the position of the Moon is such that it obscures the Sun completely. At other times, however, the outer ring of the Sun remains visible and an annular eclipse occurs. Clavius was able to observe these two types of eclipses at Coimbra in 1559 and at Rome in 1567.</p>