Ernst Karl Abbe
Encyclopedia
Ernst Karl Abbe was a German
physicist
, optometrist, entrepreneur
, and social reformer. Together with Otto Schott
and Carl Zeiss
, he laid the foundation of modern optics
. Abbe developed numerous optical instruments. He was a co-owner of Carl Zeiss AG, a German manufacturer of research microscopes, astronomical telescopes, planetariums and other optical systems.
, Saxe-Weimar-Eisenach
. He came from a humble home — his father was a foreman in a spinnery. Supported by his father's employer, Abbe was able to attend secondary school and to obtain the general qualification for university entrance with fairly good grades. By the time he left school, his scientific talent and his strong will had already become obvious. Thus, in spite of the family's strained financial situation, his father decided to support Abbe's studies at the Universities of Jena
(1857–1859) and Göttingen
(1859–1861). During his time as a student, Abbe gave private lessons to improve his income. His father's employer continued to fund him. Abbe was awarded his PhD
in Göttingen on March 23, 1861. This was followed by two short assignments at the Göttingen observatory
and at Physikalischer Verein in Frankfurt (an association of citizens interested in physics and chemistry that was founded by Johann Wolfgang von Goethe
in 1824 and still exists today). On August 8, 1863 he qualified as a university lecturer at the University of Jena. In 1870, he accepted a contract as an extraordinary professor
in Jena. In 1871, he married Else Snell, daughter of the mathematician and physicist Karl Snell, one of Abbe's teachers. He became director of the Jena observatory in 1878. In 1889, he became a member of the Bavarian Academy of Sciences and Humanities
. He also was a member of the Saxon Academy of Sciences. He was relieved of his teaching duties at the University of Jena in 1891. Abbe died January 14, 1905 in Jena.
He designed the first refractometer
, which he described in a booklet published in 1874. He created the Abbe number
, a measure of any transparent material's variation of refractive index
with wavelength
and Abbe's criterion, which tests the hypothesis that a systematic trend exists in a set of observations (in terms of resolving power this criterion stipulates that an angular separation cannot be less than the ratio of the wavelength to the aperture diameter, see angular resolution
). Already a professor in Jena
, he was hired by Carl Zeiss
to improve the manufacturing process of optical instruments, which back then was largely based on trial and error.
Abbe was the first to define the term Numerical Aperture
, as the sine of the half angle multiplied by the refractive index of the medium filling the space between the cover glass and front lens.
Abbe is credited by many for discovering the resolution limit of the microscope, and the formula
although the first known appearance of this formula was in a 1874 publication by Helmholtz, in which Helmholtz states this formula was first derived by Joseph Louis Lagrange
who had died 61 years prior. Abbe was in the camp of the wide aperturists arguing that microscopic resolution is limited the aperture of the optics, but also argued there are other parameters that should be weighted over the aperture in the design of objectives. In Abbe's 1874 paper, titled "A Contribution to the Theory of the Microscope and the nature of Microscopic Vision"., Abbe states that the resolution of a microscope is inversely dependent on its aperture, but without proposing a formula for the resolution limit of a microscope.
Although the first theoretical derivations of were published by others, it is fair to say that Abbe was the first to reach this conclusion experimentally. The objectives that the Abbe Zeiss collaboration were producing were of ideal ray geometry allowing Abbe to find that the aperture sets the upper limit of microscopic resolution, not the curvature and placement of the lenses. Abbe's first publication of occurred in 1882. In this publication Abbe states that both his theoretical and experimental investigations confirmed . Abbe's contemporary H. E. Fripp, English translator of Abbe's and Helmholtz's papers, puts their contributions on equal footing.
In order to produce high quality objectives, Abbe made significant contributions into the diagnosis and correction of Optical aberrations, which is required for an objective to reach the resolution limit of . In addition to spherical aberration, Abbe discovered that the rays in optical systems must have constant angular magnification over their angular distribution to produce a diffraction limited spot, a principle known as the Abbe sine condition
.
Abbe invented the Abbe condenser
, used for microscope illumination. During his association with Carl Zeiss
' microscope
works, he also introduced the eight-hour workday, in remembrance of the 14-hour workday of his own father.
The crater Abbe
on the Moon
was named in his honour.
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
, optometrist, entrepreneur
Entrepreneur
An entrepreneur is an owner or manager of a business enterprise who makes money through risk and initiative.The term was originally a loanword from French and was first defined by the Irish-French economist Richard Cantillon. Entrepreneur in English is a term applied to a person who is willing to...
, and social reformer. Together with Otto Schott
Otto Schott
Friedrich Otto Schott was a German chemist, glass technologist, and the inventor of borosilicate glass. He was the son of a window glass maker, Simon Schott. From 1870 to 1873 Schott studied chemical technology at the technical college in Aachen and at the universities of Würzburg and Leipzig...
and Carl Zeiss
Carl Zeiss
Carl Zeiss was a German maker of optical instruments commonly known for the company he founded, Carl Zeiss Jena . Zeiss made contributions to lens manufacturing that have aided the modern production of lenses...
, he laid the foundation of modern optics
Optics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
. Abbe developed numerous optical instruments. He was a co-owner of Carl Zeiss AG, a German manufacturer of research microscopes, astronomical telescopes, planetariums and other optical systems.
Personal life
Abbe was born January 23, 1840 in EisenachEisenach
Eisenach is a city in Thuringia, Germany. It is situated between the northern foothills of the Thuringian Forest and the Hainich National Park. Its population in 2006 was 43,626.-History:...
, Saxe-Weimar-Eisenach
Saxe-Weimar-Eisenach
The Duchy of Saxe-Weimar-Eisenach was created in 1809 by the merger of the Ernestine duchies of Saxe-Weimar and Saxe-Eisenach. It was raised to a Grand duchy in 1815 by resolution of the Vienna Congress. In 1877, it officially changed its name to the Grand Duchy of Saxony , but this name was...
. He came from a humble home — his father was a foreman in a spinnery. Supported by his father's employer, Abbe was able to attend secondary school and to obtain the general qualification for university entrance with fairly good grades. By the time he left school, his scientific talent and his strong will had already become obvious. Thus, in spite of the family's strained financial situation, his father decided to support Abbe's studies at the Universities of Jena
Jena
Jena is a university city in central Germany on the river Saale. It has a population of approx. 103,000 and is the second largest city in the federal state of Thuringia, after Erfurt.-History:Jena was first mentioned in an 1182 document...
(1857–1859) and Göttingen
Göttingen
Göttingen is a university town in Lower Saxony, Germany. It is the capital of the district of Göttingen. The Leine river runs through the town. In 2006 the population was 129,686.-General information:...
(1859–1861). During his time as a student, Abbe gave private lessons to improve his income. His father's employer continued to fund him. Abbe was awarded his PhD
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
in Göttingen on March 23, 1861. This was followed by two short assignments at the Göttingen observatory
Observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...
and at Physikalischer Verein in Frankfurt (an association of citizens interested in physics and chemistry that was founded by Johann Wolfgang von Goethe
Johann Wolfgang von Goethe
Johann Wolfgang von Goethe was a German writer, pictorial artist, biologist, theoretical physicist, and polymath. He is considered the supreme genius of modern German literature. His works span the fields of poetry, drama, prose, philosophy, and science. His Faust has been called the greatest long...
in 1824 and still exists today). On August 8, 1863 he qualified as a university lecturer at the University of Jena. In 1870, he accepted a contract as an extraordinary professor
Professor
A professor is a scholarly teacher; the precise meaning of the term varies by country. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences; a teacher of high rank...
in Jena. In 1871, he married Else Snell, daughter of the mathematician and physicist Karl Snell, one of Abbe's teachers. He became director of the Jena observatory in 1878. In 1889, he became a member of the Bavarian Academy of Sciences and Humanities
Bavarian Academy of Sciences and Humanities
The Bavarian Academy of Sciences and Humanities is an independent public institution, located in Munich. It appoints scholars whose research has contributed considerably to the increase of knowledge within their subject...
. He also was a member of the Saxon Academy of Sciences. He was relieved of his teaching duties at the University of Jena in 1891. Abbe died January 14, 1905 in Jena.
Life work
Refractometer
A refractometer is a laboratory or field device for the measurement of an index of refraction . The index of refraction is calculated from Snell's law and can be calculated from the composition of the material using the Gladstone-Dale relation....
, which he described in a booklet published in 1874. He created the Abbe number
Abbe number
In physics and optics, the Abbe number, also known as the V-number or constringence of a transparent material, is a measure of the material's dispersion in relation to the refractive index...
, a measure of any transparent material's variation of refractive index
Refractive index
In optics the refractive index or index of refraction of a substance or medium is a measure of the speed of light in that medium. It is expressed as a ratio of the speed of light in vacuum relative to that in the considered medium....
with wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
and Abbe's criterion, which tests the hypothesis that a systematic trend exists in a set of observations (in terms of resolving power this criterion stipulates that an angular separation cannot be less than the ratio of the wavelength to the aperture diameter, see angular resolution
Angular resolution
Angular resolution, or spatial resolution, describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object...
). Already a professor in Jena
Jena
Jena is a university city in central Germany on the river Saale. It has a population of approx. 103,000 and is the second largest city in the federal state of Thuringia, after Erfurt.-History:Jena was first mentioned in an 1182 document...
, he was hired by Carl Zeiss
Carl Zeiss
Carl Zeiss was a German maker of optical instruments commonly known for the company he founded, Carl Zeiss Jena . Zeiss made contributions to lens manufacturing that have aided the modern production of lenses...
to improve the manufacturing process of optical instruments, which back then was largely based on trial and error.
Abbe was the first to define the term Numerical Aperture
Numerical aperture
In optics, the numerical aperture of an optical system is a dimensionless number that characterizes the range of angles over which the system can accept or emit light. By incorporating index of refraction in its definition, NA has the property that it is constant for a beam as it goes from one...
, as the sine of the half angle multiplied by the refractive index of the medium filling the space between the cover glass and front lens.
Abbe is credited by many for discovering the resolution limit of the microscope, and the formula
although the first known appearance of this formula was in a 1874 publication by Helmholtz, in which Helmholtz states this formula was first derived by Joseph Louis Lagrange
Joseph Louis Lagrange
Joseph-Louis Lagrange , born Giuseppe Lodovico Lagrangia, was a mathematician and astronomer, who was born in Turin, Piedmont, lived part of his life in Prussia and part in France, making significant contributions to all fields of analysis, to number theory, and to classical and celestial mechanics...
who had died 61 years prior. Abbe was in the camp of the wide aperturists arguing that microscopic resolution is limited the aperture of the optics, but also argued there are other parameters that should be weighted over the aperture in the design of objectives. In Abbe's 1874 paper, titled "A Contribution to the Theory of the Microscope and the nature of Microscopic Vision"., Abbe states that the resolution of a microscope is inversely dependent on its aperture, but without proposing a formula for the resolution limit of a microscope.
Although the first theoretical derivations of were published by others, it is fair to say that Abbe was the first to reach this conclusion experimentally. The objectives that the Abbe Zeiss collaboration were producing were of ideal ray geometry allowing Abbe to find that the aperture sets the upper limit of microscopic resolution, not the curvature and placement of the lenses. Abbe's first publication of occurred in 1882. In this publication Abbe states that both his theoretical and experimental investigations confirmed . Abbe's contemporary H. E. Fripp, English translator of Abbe's and Helmholtz's papers, puts their contributions on equal footing.
In order to produce high quality objectives, Abbe made significant contributions into the diagnosis and correction of Optical aberrations, which is required for an objective to reach the resolution limit of . In addition to spherical aberration, Abbe discovered that the rays in optical systems must have constant angular magnification over their angular distribution to produce a diffraction limited spot, a principle known as the Abbe sine condition
Abbe sine condition
The Abbe sine condition is a condition that must be fulfilled by a lens or other optical system in order for it to produce sharp images of off-axis as well as on-axis objects...
.
Abbe invented the Abbe condenser
Abbe condenser
A condenser is one of the main components of the optical system of many transmitted light compound microscopes. A condenser is a lens that serves to concentrate light from the illumination source that is in turn focused through the object and magnified by the objective lens. It is a basic component...
, used for microscope illumination. During his association with Carl Zeiss
Carl Zeiss
Carl Zeiss was a German maker of optical instruments commonly known for the company he founded, Carl Zeiss Jena . Zeiss made contributions to lens manufacturing that have aided the modern production of lenses...
' microscope
Microscope
A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...
works, he also introduced the eight-hour workday, in remembrance of the 14-hour workday of his own father.
The crater Abbe
Abbe (crater)
Abbe is a lunar impact crater that is located in the southern hemisphere on the far side of the Moon. It is located just to the south of the crater Hess, and lies to the east of the large walled basin Poincaré. It is named after the German physicist Ernst Abbe.The outer wall of Abbe is somewhat...
on the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
was named in his honour.
See also
- Abbe prismAbbe prismIn optics, an Abbe prism, named for its inventor, the German physicist Ernst Abbe, is a type of constant deviation dispersive prism similar to a Pellin–Broca prism.-Structure:...
- Abbe refractometerAbbe refractometerAn Abbe refractometer is a bench-top device for the high-precision measurement of an index of refraction.- Details :Ernst Abbe , working for the Zeiss Company in Jena, Germany in the late 19th century, was the first to develop a laboratory refractometer...
- Abbe errorAbbe errorAbbe error, named after Ernst Abbe, also called sine error, describes the magnification of angular error over distance. For example, when one measures a point that is 1 meter away at 45 degrees, an angular error of 1 degree corresponds to a positional error of over 1.745 cm, equivalent to a...
- Aberration in optical systemsAberration in optical systemsAberrations are departures of the performance of an optical system from the predictions of paraxial optics. Aberration leads to blurring of the image produced by an image-forming optical system. It occurs when light from one point of an object after transmission through the system does not converge...
- Calculation of glass propertiesCalculation of glass propertiesThe calculation of glass properties is used to predict glass properties of interest or glass behavior under certain conditions without experimental investigation, based on past data and experience, with the intention to save time, material, financial, and environmental resources, or to gain...
- German inventors and discoverersGerman inventors and discoverersThis is a list of German inventors and discoverers. The following list comprises people from Germany or German-speaking Europe, also of people of predominantly German heritage, in alphabetical order of the surname. The main section includes existing articles, indicated by blue links, and possibly...
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External links
- Basic Principles of Refractometers (and Polarimeters)
- Molecular Expressions's biography
- Abbe Refractometer by Carl Zeiss made in 1904