Mangin mirror

Last updated
Diagram of a Mangin mirror. Mangin mirror.svg
Diagram of a Mangin mirror.

In optics, a Mangin mirror is a negative meniscus lens with the reflective surface on the rear side of the glass forming a curved mirror that reflects light without spherical aberration if certain conditions are met. This reflector was invented in 1876 by a French officer Alphonse Mangin [1] [2] as an improved catadioptric reflector for search lights and is also used in other optical devices.



The Mangin mirror's construction consists of a concave (negative meniscus) lens made of crown glass with spherical surfaces of different radii with the reflective coating on the shallower rear surface. The spherical aberration normally produced by the simple spherical mirror surface is canceled out by the opposite spherical aberration produced by the light traveling through the negative lens. Since light passes through the glass twice, the overall system acts like a triplet lens. [3] The Mangin mirror was invented in 1876 by a French military engineer named Colonel Alphonse Mangin as a substitute for the more difficult to manufacture parabolic reflecting mirror for use in searchlights. Since the catadioptric design eliminated most of the off-axis aberration found in parabolic mirrors, Mangin mirrors had the added advantage of producing a nearly true parallel beam of light. They saw use in the late 19th century as reflectors for naval search lights. Its use in military applications was limited, since glass reflectors of any kind were thought to be too fragile and susceptible to enemy gunfire. [4]


Example of a catadioptric lens that uses rear surfaced "mangin mirrors" (Minolta RF Rokkor-X 250mm f/5.6) MinoltaRFRokkorX250f56text.svg
Example of a catadioptric lens that uses rear surfaced "mangin mirrors" (Minolta RF Rokkor-X 250mm f/5.6)

Mangin mirrors are used in illumination and image forming optics such as search lights, headlamps, aircraft gunsights and head-mounted displays. Many catadioptric telescopes use negative lenses with a reflective coating on the back surface that are referred to as "Mangin mirrors", although they are not single-element objectives like the original Mangin, and some, like the Hamiltonian telescope, predate the Mangin's invention by over 60 years. [5] Catadioptric mirrors similar to the Mangin are found in the Klevtsov–Cassegrain, Argunov–Cassegrain telescopes, and Ludwig Schupmann's Schupmann medial telescope. [6] They are also used in compact catadioptric photographic lens designs that save on mass since aberration can be corrected by the mirror, itself. [7] Mangin mirrors are also used in null correctors, which are used to fabricate large aspheric mirrors. [8]


  1. Wide-field telescopes with a Mangin mirror - V. Yu. Terebizh
  2. Britannica
  3. Optical design fundamentals for infrared systems By Max J. Riedl
  4. Jean Alexandre Rey, John Henry Johnson, The range of electric searchlight projectors, 1917 - page 62
  6. Sacek, Vladimir (2006-07-14). "11.1.2. Schupmann "medial" telescope". Telescope Optics. Vladimir Sacek. Retrieved 2009-07-05.
  7. About – the 500mm F/8 Tele-Macro Catadioptric
  8. Burge, J.H. (1993). "Advanced Techniques for Measuring Primary Mirrors for Astronomical Telescopes" (PDF). Ph.D. Thesis, University of Arizona. p. 168.

Related Research Articles

Parabolic reflector Reflector that has the shape of a paraboloid

A parabolicreflector is a reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis. The parabolic reflector transforms an incoming plane wave travelling along the axis into a spherical wave converging toward the focus. Conversely, a spherical wave generated by a point source placed in the focus is reflected into a plane wave propagating as a collimated beam along the axis.

Ritchey–Chrétien telescope Specialized Cassegrain telescope

A Ritchey–Chrétien telescope is a specialized variant of the Cassegrain telescope that has a hyperbolic primary mirror and a hyperbolic secondary mirror designed to eliminate off-axis optical errors (coma). The RCT has a wider field of view free of optical errors compared to a more traditional reflecting telescope configuration. Since the mid 20th century, a majority of large professional research telescopes have been Ritchey–Chrétien configurations; some well-known examples are the Hubble Space Telescope, the Keck telescopes and the ESO Very Large Telescope.

Spherical aberration Optical aberration

In optics, spherical aberration (SA) is a type of aberration found in optical systems that have elements with spherical surfaces. Lenses and curved mirrors are prime examples, because this shape is easier to manufacture. Light rays that strike a spherical surface off-centre are refracted or reflected more or less than those that strike close to the centre. This deviation reduces the quality of images produced by optical systems.

Optical telescope Telescope for observations with visible light

An optical telescope is a telescope that gathers and focuses light mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct visual inspection, to make a photograph, or to collect data through electronic image sensors.

Reflecting telescope Telescopes which utilize curved mirrors to form an image

A reflecting telescope is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic aberration. Although reflecting telescopes produce other types of optical aberrations, it is a design that allows for very large diameter objectives. Almost all of the major telescopes used in astronomy research are reflectors. Reflecting telescopes come in many design variations and may employ extra optical elements to improve image quality or place the image in a mechanically advantageous position. Since reflecting telescopes use mirrors, the design is sometimes referred to as a catoptric telescope.

Schmidt corrector plate Corrective lens used in Schmidt and Schmidt–Cassegrain telescopes

A Schmidt corrector plate is an aspheric lens which corrects the spherical aberration introduced by the spherical primary mirror of the Schmidt or Schmidt–Cassegrain telescope designs. It was invented by Bernhard Schmidt in 1931, although it may have been independently invented by Finnish astronomer Yrjö Väisälä in 1924. Schmidt originally introduced it as part of a wide-field photographic catadioptric telescope, the Schmidt camera. It is now used in several other telescope designs, camera lenses and image projection systems that utilise a spherical primary mirror.

Newtonian telescope Type of reflecting telescope

The Newtonian telescope, also called the Newtonian reflector or just the Newtonian, is a type of reflecting telescope invented by the English scientist Sir Isaac Newton (1642–1727), using a concave primary mirror and a flat diagonal secondary mirror. Newton's first reflecting telescope was completed in 1668 and is the earliest known functional reflecting telescope. The Newtonian telescope's simple design has made it very popular with amateur telescope makers.

Coma (optics) Aberration inherent to certain optical designs or due to imperfection in the lens

In optics, the coma, or comatic aberration, in an optical system refers to aberration inherent to certain optical designs or due to imperfection in the lens or other components that results in off-axis point sources such as stars appearing distorted, appearing to have a tail (coma) like a comet. Specifically, coma is defined as a variation in magnification over the entrance pupil. In refractive or diffractive optical systems, especially those imaging a wide spectral range, coma can be a function of wavelength, in which case it is a form of chromatic aberration.

Focus (optics) Point in an optical system where light rays originating from a point on the object converge

In geometrical optics, a focus, also called an image point, is a point where light rays originating from a point on the object converge. Although the focus is conceptually a point, physically the focus has a spatial extent, called the blur circle. This non-ideal focusing may be caused by aberrations of the imaging optics. In the absence of significant aberrations, the smallest possible blur circle is the Airy disc, which is caused by diffraction from the optical system's aperture. Aberrations tend to worsen as the aperture diameter increases, while the Airy circle is smallest for large apertures.

Dmitry Dmitrievich Maksutov

Dmitry Dmitrievich Maksutov was a Russian / Soviet optical engineer and amateur astronomer. He is best known as the inventor of the Maksutov telescope.

Catadioptric system Optical system where refraction and reflection are combined

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, headlamps, early lighthouse focusing systems, optical telescopes, microscopes, and telephoto lenses. Other optical systems that use lenses and mirrors are also referred to as "catadioptric", such as surveillance catadioptric sensors.

Maksutov telescope Catadioptric telescope design

The Maksutov is a catadioptric telescope design that combines a spherical mirror with a weakly negative meniscus lens in a design that takes advantage of all the surfaces being nearly "spherically symmetrical". The negative lens is usually full diameter and placed at the entrance pupil of the telescope. The design corrects the problems of off-axis aberrations such as coma found in reflecting telescopes while also correcting chromatic aberration. It was patented in 1941 by Russian optician Dmitri Dmitrievich Maksutov. Maksutov based his design on the idea behind the Schmidt camera of using the spherical errors of a negative lens to correct the opposite errors in a spherical primary mirror. The design is most commonly seen in a Cassegrain variation, with an integrated secondary, that can use all-spherical elements, thereby simplifying fabrication. Maksutov telescopes have been sold on the amateur market since the 1950s.

Schmidt–Cassegrain telescope Type of catadioptric telescope

The Schmidt–Cassegrain is a catadioptric telescope that combines a Cassegrain reflector's optical path with a Schmidt corrector plate to make a compact astronomical instrument that uses simple spherical surfaces.

Cassegrain reflector Combination of concave and convex mirrors

The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas, the main characteristic being that the optical path folds back onto itself, relative to the optical system's primary mirror entrance aperture. This design puts the focal point at a convenient location behind the primary mirror and the convex secondary adds a telephoto effect creating a much longer focal length in a mechanically short system.

Argunov–Cassegrain telescope

The Argunov–Cassegrain telescope is a catadioptric telescope design first introduced in 1972 by P. P. Argunov. All optics are spherical, and the classical Cassegrain secondary mirror is replaced by a sub-aperture secondary corrector group consisting of three air-spaced elements, two lenses and a Mangin mirror.

Lurie–Houghton telescope

The Houghton telescope or Lurie–Houghton telescope is a catadioptric telescope. Houghton's original design was patented in 1944. Instead of the fairly hard to make Schmidt and heavy meniscus (Maksutov) corrector lenses, the corrector for the Houghton is relatively easy to make. It consists of two lenses: a positive and a negative, set at the front of the telescope which fixes the telescope's aperture. All lens and mirror surfaces are spheroidal, which eases construction. These lenses are relatively thin, though not as thin as the Schmidt corrector. With a good anti-reflective coating, light loss and "ghost" reflections are minimal.


An anastigmat or anastigmatic lens is a photographic lens completely corrected for the three main optical aberrations: spherical aberration, coma, and astigmatism. Early lenses often included the word Anastigmat in their name to advertise this new feature. The first Anastigmat was designed by Paul Rudolph for the German firm Carl Zeiss AG in 1890.

Klevtsov–Cassegrain telescope

The Klevtsov–Cassegrain telescope is a type of catadioptric Cassegrain telescope that uses a spherical primary mirror and a sub-aperture secondary corrector group composed of a small lens and a Mangin mirror.

Meniscus corrector

A meniscus corrector is a negative meniscus lens that is used to correct spherical aberration in image-forming optical systems such as catadioptric telescopes. It works by having the equal but opposite spherical aberration of the objective it is designed to correct.