Eyepiece
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An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as telescopes and microscopes. It is named because it is usually the lens that is closest to the ey
A collection of different types of eyepieces.
A 25 mm Kellner eyepiece
Simulation of views through a telescope using different eyepieces. The center image uses an eyepiece of the same focal length as the one on the left, but has a wider apparent field of view giving a larger image that shows more area. The image on the right has the same apparent field of view as the center eyepiece but has a shorter focal length, giving the same true field of view as the left image but at higher magnification.
The Plössl, an eyepiece with a large apparent field of view
Christiaan Huygens
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Christiaan Huygens, Lord of Zeelhem was a Dutch mathematician, physicist, engineer, astronomer, and inventor who is regarded as a key figure in the Scientific Revolution. In physics, Huygens made semi
Eyepiece
…observer's eye is called the eye lens and the other lens is called field lens. The focal plane is located between the two lenses. It was invented by Christiaan Huygens in the late 1660s and was the first compound (multi-lens) eyepiece. Huygens discovered that two air spaced lenses can be used to make an eyepiece with…
Portrait by Caspar Netscher, 1671
Christiaan Huygens, relief by Jean-Jacques Clérion (c. 1670)
Huygens, right of centre, from L'établissement de l'Académie des Sciences et fondation de l'observatoire, 1666 by Henri Testelin (c. 1675)
Hofwijck, Huygens's summer home; now a museum