Ars Magna Lucis et Umbrae

Ars Magna Lucis et Umbrae ("The Great Art of Light and Shadow") is a 1645 work by the Jesuit scholar Athanasius Kircher.

[4]: 15 Ars magna lucis et umbrae followed soon after Kircher's work on magnetism, Magnes sive de Arte Magnetica (1641) and the title was a play on words.

[7]: 23 Kircher dealt comprehensively with many different aspects of light, including physical, astronomical, astrological and metaphysical.

By the time the second edition was published in 1671, it was understood that Saturn had rings and not two large satellites, but Kircher did not correct the illustration and it was reprinted unchanged.

Immediately below this are represented the two highest means by which humans can understand God's plan, sacred authority ('auctoritas sacra') and reason ('ratio').

Facing the sun-god is the moon-goddess, covered in stars and holding a shield which reflects the light of the Sun down to the Earth below.

Beneath her a finger points to the fourth source of knowledge, the senses ('sensus'), represented by a telescope casting an image of the sun onto a sheet of paper.

[4]: 23–28 [10][11] Ars Magna Lucis et Umbrae contained many designs for sundials and related devices, including a large foldout sheet that allowed the user to know the time in every part of the world where the Jesuits had missions.

[12][4]: 202 Kircher's unusual depiction of the magic lantern has been taken by some critics to mean that he had not actually built one or seen it operate, since the illustration shows the mirror not properly alighted with the light source and the glass slider appears in front of the lens tube rather than behind it.

Some argue that these anomalies are due to mistakes by the Dutch publisher Waesberghe; however others hold that the mechanism would work as depicted and that it was a variant of the normal type, designed as an analogicical demonstration of the Neoplatonic metaphysics of light.