Blaev, Guilielmi Janszoo

Guilielmi Janszoo Blaev (1571–1638)

INSTITVTIO ASTRONOMICA, Amstelaedami 1668

paper, binding: cardboard, covered with white leather; 190×108 cm, Olomouc Archbishopric – Archdiocesan Museum in Kroměříž, 5627, I3 I 23

The front cover shows Ptolemys globe blending in with Copernicus system. To a great extent this refers to the contents of the work, which are based on a comparison between Ptolemys geocentric system and Copernicus heliocentric system. Blaev gives practical advice on the use of globes, in relation to armillary spheres (they were used to determine equatorial coordinates and the position of celestial bodies) and sundials. The text contains numerical astronomical charts as well as numerous illustrations. The work was first published in Dutch and Latin in 1634 and has been re-published many times since.

Cyril Měsíc