Sep 20 – 25, 2026
University of Graz
Europe/Vienna timezone

Astronomical Use of Camera Obscura to Monitor Solar Eclipses before Telescope’s Area

Sep 21, 2026, 5:00 PM
20m
HS 05.01 (University of Graz)

HS 05.01

University of Graz

05 - Physics, ground floor
3) Contributed talk GEP: History of Physics Parallel

Speaker

Mohammed BOUDJADA (Space Research Institute, Austrian Academy of Sciences, Graz, Austria)

Description

It is well-known that Kepler (1571-1630) provided optical principle of the telescope, the astronomical lunette, to Galileo (1564-1642), who used it to discover and investigate physical aspects of the Moon, and Jupiter’s satellites. Kepler’s knowledge was not restricted to the telescope (i.e., lens, objective and ocular) but included also the optics known since Greeks. In this study, we attempt to examine the instrumental role of the camera obscura, or pinhole, at the end of sixteenth century and the beginning of the seventeenth one. This time interval marks the emergence of the heliocentric system mainly due to the high accuracy of the observations, and the ‘mathematization’ of the instrument concepts, as well the separation from astrology and astronomy. Hence, the camera obscura was used for Solar eclipse observations despite the complexity of the measurement interpretations. Kepler attempted in Graz to plan the observation of the Solar eclipse of 10 July 1600, never detailed the outcomes but reported about other eclipses. Through this work, we emphasize on the progressive evolution of the camera obscura as an astronomical instrument, and discuss Kepler’s approaches to solve the optical difficulties faced during the Solar eclipses.

Author

Mohammed BOUDJADA (Space Research Institute, Austrian Academy of Sciences, Graz, Austria)

Co-author

Bruno BESSER (Space Research Institute, Austrian Academy of Sciences, Graz, Austria)

Presentation materials

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