1750 - 1774

How to halt the sun? That was the question for physicists in the eighteenth century (when there was no electric light), who were dependent of the light of the sun for their optical experiments or the illumination of preparations under a microscope (See also the solar microscope 1229). It was disturbing that the incident sunlight in a room was continually changing its direction and its angle under influence of the movement of the sun along the sky. To solve this problem, the Leiden professor Willem Jacob ’s Gravesande developed the heliostat or ‘sun stagnator’. Via a mirror, which is continually being adjusted by a clockwork, the sunlight is always reflected to the same spot. With this prolonged stationary light beam, experiments could be carried out undisturbed.

Administration name

Fysisch Kabinet



Translated title



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[{'material': 'brass'}, {'material': 'steel'}]

Object number

FK 0308

Reproduction reference

[{'reference': '..\\images\\Fysisch\\Gekoppelde afbeeldingen\\FK 0308.jpg'}]