Fresnel lighthouse lens diagram

Författare/Upphovsman:

Adolphe Ganot

Kreditera:

Downloaded from Adolphe Ganot (1872) Natural Philosophy for General Readers and Young Persons, D. Appleton & Co., New York, p.328, fig.257 (translated with permission from Ganot's Cours Élémentaire de Physique by Edmund Atkinson)

Kort länk:

https://sewiki.info/b/bf43e

Källa:

Wikimedia Commons

Upplösning:

492 x 578 Pixel (90202 Bytes)

Beskrivning:

Section diagram showing how a Fresnel lens (A) in a lighthouse works to collimate light from an oil lamp (L) into a parallel beam. The Fresnel lens, invented in 1822 by Augustin-Jean Fresnel, increased the light projecting power of lighthouses greatly without the weight of a conventional lens of its size. Also shown are mirror strips (m,n) mounted above and below the lens that most lighthouses had, to gather more of the lamp's light. Alterations: removed caption, erased blots in white areas, changed brightness levels to get rid of noise in white areas, sharpened light path lines.

Licens:

Public domain

Licenskommentaren:

Public domain - Ganot died in 1887; published in USA before 1923