[AUDIO : _Geometrical optics: the optics of everyday life_](OG_intro.mp3)
#### Geometrical optics lets us understand :
* The **Vision**
***Optical instruments** : * magnifiers, telescopes, microscopes, cameras with telephoto and macro lenses*
***Eyeglasses and contact lenses** to correct vision defects.
* Optical phenomena such as **fog, rainbows, mirages**.
* The operation of a **fiber optic**.
<!--text of the audio:
If geometric optics is the oldest science of optics, it is really the one that applies to the closest to our everyday life.
It helps to understand how the eye perceives its environment. It also helps to understand how conventional optical devices work, such as the camera with its zoom or various lenses, the microscope, the telescope and the astronomical or terrestrial glasses.
It also makes it possible to characterize the defects of the eye, to understand how eyeglasses and contact lenses correct these defects, and to calculate their profiles according to the defects to be corrected.
It allows to understand the optical phenomena like the rainbow (as well its colors as its shape and its position with respect to the sun) and like the mirages observed sometimes in the desert.
Finally, it allows us to understand how light can propagate in an optical fiber, which is at the base of all modern terrestrial communication networks.-->
#### Geometrical optics : the oldest science of optics
*Chronological vision*, brief and imperfect, *dated from the present time*
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*dates* | *in Gregorian calendar (usual calendarl)*
<spanstyle="color: #0066cc">•≈ -2500 </span> | <spanstyle="color: #0066cc">premières fabrications en verre translucide, en Mésopotamie et Égypte.</span>
<spanstyle="color: #0066cc">• -2000 à -1000</span> | <spanstyle="color: #0066cc">divers éléments en quartz volontairement polis</span>
<spanstyle="color: #0066cc">• -850 ± 150 </span> | <spanstyle="color: #0066cc">la *lentille de Nimrud*, peut-être plus ancien instrument d'optique jamais découvert.</span>
<spanstyle="color: #0066cc">• > 200</span> | <spanstyle="color: #0066cc">1ère apogée *techniques des miroirs et du verre transparent* (entre autre pour vitrage).</span>
<spanstyle="color: #0066cc">• 1285</span> | <spanstyle="color: #0066cc">*Alexandro della Spina* : invention des *lunettes de vue*.</span>
<spanstyle="color: #0066cc">•≈1550</span> | <spanstyle="color: #0066cc">inventions des *lunettes terrestres et astronomiques*.</span>
<spanstyle="color: #0066cc">•[1514;1570]</span> | <spanstyle="color: #0066cc">*Barbaro* améliore chambre obscure grâce à lentille convergente (*ancêtre appareils photo*).</span>
<spanstyle="color: #0066cc">• 1590</span> | <spanstyle="color: #0066cc">invention du *microscope* attribuée à *Janssen*</span>
<spanstyle="color: #0066cc">• 1608</span> | <spanstyle="color: #0066cc">*Lippershey et Metius* : invention du *télescope*</span>
<spanstyle="color: #993333">• 1621 et 1637</span> | <spanstyle="color: #993333">*Snell* et *Descartes* : *loi de la réfraction*.</span>
<spanstyle="color: #993333">•[1601;1665]</span> | <spanstyle="color: #993333">*Fermat* : énoncé du *principe de Fermat*, base conceptuelle de l'optique géométrique.</span>
<spanstyle="color: #0066cc">• de 1816 et 1824</span> | <spanstyle="color: #0066cc">Niépce : mise au point de l'appareil photographique et première photographie. Le défi était "chimique", pour fixer l'image.</span>
<spanstyle="color: #0066cc">• de 1840 à1850]</span> | <spanstyle="color: #0066cc">*Démonstration expérimentale* de la *réflexion totale* à l'interface de deux matériaux trasnparents.</span>
<spanstyle="color: #0066cc">• 1852</span> | <spanstyle="color: #0066cc">*Charrière et Désormeaux : premiers endoscopes* pour usages médicaux</span>
<spanstyle="color: #0066cc">• 1927</span> | <spanstyle="color: #0066cc">*Baird et Hansell*: brevet utilisation *fibre optique pour transmission d'images* de télévision.</span>
