Dioptrics is the branch of
optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of optical instruments, instruments that use or Photodetector, detect it. Optics usually describes t ...
dealing with
refraction
In physics, refraction is the redirection of a wave as it passes from one transmission medium, medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commo ...
, especially by
lenses
A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
. In contrast, the branch dealing with
mirror
A mirror, also known as a looking glass, is an object that Reflection (physics), reflects an image. Light that bounces off a mirror forms an image of whatever is in front of it, which is then focused through the lens of the eye or a camera ...
s is known as ''
catoptrics
Catoptrics (from ''katoptrikós'', "specular", from ''katoptron'' "mirror") deals with the phenomena of reflected light and image-forming optical systems using mirrors. A catoptric system is also called a ''catopter'' (''catoptre'').
Histor ...
''.
Telescopes
A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...
that create their image with an
objective
Objective may refer to:
* Objectivity, the quality of being confirmed independently of a mind.
* Objective (optics), an element in a camera or microscope
* ''The Objective'', a 2008 science fiction horror film
* Objective pronoun, a personal pron ...
that is a
convex lens
A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements'') ...
(
refractors) are said to be "dioptric" telescopes.
An early study of dioptrics was conducted by
Ptolemy
Claudius Ptolemy (; , ; ; – 160s/170s AD) was a Greco-Roman mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine science, Byzant ...
in relationship to the human eye as well as refraction in media such as water. The understanding of the principles of dioptrics was further expanded by
Alhazen
Ḥasan Ibn al-Haytham ( Latinized as Alhazen; ; full name ; ) was a medieval mathematician, astronomer, and physicist of the Islamic Golden Age from present-day Iraq.For the description of his main fields, see e.g. ("He is one of the princ ...
, considered the
father of modern optics.
See also
*
Diopter
A dioptre ( British spelling) or (American spelling), symbol dpt or D, is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, . It is normally used to express the optical power of a lens or curved mi ...
/
Dioptre
A dioptre ( British spelling) or (American spelling), symbol dpt or D, is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, . It is normally used to express the optical power of a lens or curved mi ...
(unit of measurement)
*
Dioptrice
Johannes Kepler (27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws of p ...
(work by Johannes Kepler)
*
Catoptrics
Catoptrics (from ''katoptrikós'', "specular", from ''katoptron'' "mirror") deals with the phenomena of reflected light and image-forming optical systems using mirrors. A catoptric system is also called a ''catopter'' (''catoptre'').
Histor ...
(study of and optical systems utilizing reflection)
*
Catadioptrics
A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses (dioptrics) and curved mirrors (catoptrics). Catadioptric combinations are used in focusing systems such as searchlights, ...
(study of and optical systems utilizing reflection and refraction)
*
Optical telescope
An optical telescope gathers and focus (optics), focuses light mainly from the visible spectrum, visible part of the electromagnetic spectrum, to create a magnification, magnified image for direct visual inspection, to make a photograph, or to co ...
*
List of telescope types
The following are lists of devices categorized as types of telescopes or devices associated with telescopes. They are broken into major classifications with many variations due to professional, amateur, and commercial sub-types. Telescopes can be c ...
*
Image-forming optical system
References
Telescopes
Optics
{{Optics-stub