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Karl Strehl
Karl Wilhelm Andreas Strehl (April 30, 1864 – June 14, 1940) was a German physicist, mathematician, and writer. He is notable for the Strehl ratio, a widely used measurement for the optical quality of an imaging system.Strehl, K. 1902, ''Über Luftschlieren und Zonenfehler'', Zeitschrift für Instrumentenkunde, 22 (July), 213–217[PDF file]/ref> See also * Strehl ratio The Strehl ratio is a measure of the quality of optical image formation, originally proposed by Karl Strehl, after whom the term is named. Used variously in situations where optical resolution is compromised due to lens aberrations or due to ima ... References 1864 births 1940 deaths 20th-century German physicists German male writers 19th-century German mathematicians 20th-century German mathematicians 19th-century German physicists {{Germany-physicist-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of Phenomenon, phenomena, and usually frame their understanding in mathematical terms. They work across a wide range of Physics#Research fields, research fields, spanning all length scales: from atom, sub-atomic and particle physics, through biological physics, to physical cosmology, cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: Experimental physics, experimental physicists who specialize in the observation of natural phenomena and the development and analysis of experiments, and Theoretical physics, theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strehl Ratio
The Strehl ratio is a measure of the quality of optical image formation, originally proposed by Karl Strehl, after whom the term is named. Used variously in situations where optical resolution is compromised due to lens aberrations or due to imaging through the turbulent atmosphere, the Strehl ratio has a value between 0 and 1, with a hypothetical, perfectly unaberrated optical system having a Strehl ratio of 1. Mathematical definition The Strehl ratio S is frequently defined as the ratio of the peak aberrated image intensity from a point source compared to the maximum attainable intensity using an ideal optical system limited only by diffraction over the system's aperture. It is also often expressed in terms not of the peak intensity but the intensity at the image center (intersection of the optical axis with the focal plane) due to an on-axis source; in most important cases these definitions result in a very similar figure (or identical figure, when the point of peak intensity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1864 Births
Events January * January 13 – American songwriter Stephen Foster ("Oh! Susanna", "Old Folks at Home") dies aged 37 in New York City, leaving a scrap of paper reading "Dear friends and gentle hearts". His parlor song "Beautiful Dreamer" is published in March. * January 16 – Denmark rejects an Austrian-Prussian ultimatum to repeal the Danish Constitution, which says that Schleswig-Holstein is part of Denmark. * January 21 – New Zealand Wars: The Tauranga campaign begins. February * February – John Wisden publishes ''Wisden Cricketers' Almanack, The Cricketer's Almanack for the year 1864'' in England; it will go on to become the major annual cricket reference publication. * February 1 – Danish-Prussian War (Second Schleswig War): 57,000 Austrian and Prussian troops cross the Eider River into Denmark. * February 15 – Heineken N.V., Heineken Brewery is founded in the Netherlands. *American Civil War: ** February 17 – The tiny Confed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1940 Deaths
A calendar from 1940 according to the Gregorian calendar, factoring in the dates of Easter and related holidays, cannot be used again until the year 5280. Events Below, events related to World War II have the "WWII" prefix. January *January 4 – WWII: Luftwaffe Chief and Generalfeldmarschall Hermann Göring assumes control of most war industries in Nazi Germany, Germany, in his capacity as Plenipotentiary for the Four Year Plan. *January 6 – WWII: Winter War – General Semyon Timoshenko takes command of all Soviet forces. *January 7 – WWII: Winter War: Battle of Raate Road – Outnumbered Finnish troops decisively defeat Soviet forces. *January 8 – WWII: **Winter War: Battle of Suomussalmi – Finnish forces destroy the 44th Rifle Division (Soviet Union), Soviet 44th Rifle Division. **Food rationing in the United Kingdom begins; it will remain in force until 1954. *January 9 – WWII: British submarine is sunk in the Heligoland Bight. *January 10 – WWII: Mechele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
German Male Writers
German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also German nationality law **Germanic peoples (Roman era) * German diaspora * German language * German cuisine, traditional foods of Germany People * German (given name) * German (surname) * Germán, a Spanish name Places * German (parish), Isle of Man * German, Albania, or Gërmej * German, Bulgaria * German, Iran * German, North Macedonia * German, New York, U.S. * Agios Germanos, Greece Other uses * German (mythology), a South Slavic mythological being * Germans (band), a Canadian rock band * "German" (song), a 2019 song by No Money Enterprise * ''The German'', a 2008 short film * "The Germans", an episode of ''Fawlty Towers'' * ''The German'', a nickname for Congolese rebel André Kisase Ngandu See also * Germanic (disa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
19th-century German Mathematicians
The 19th century began on 1 January 1801 (represented by the Roman numerals MDCCCI), and ended on 31 December 1900 (MCM). It was the 9th century of the 2nd millennium. It was characterized by vast social upheaval. Slavery was abolished in much of Europe and the Americas. The First Industrial Revolution, though it began in the late 18th century, expanded beyond its British homeland for the first time during the 19th century, particularly remaking the economies and societies of the Low Countries, France, the Rhineland, Northern Italy, and the Northeastern United States. A few decades later, the Second Industrial Revolution led to ever more massive urbanization and much higher levels of productivity, profit, and prosperity, a pattern that continued into the 20th century. The Catholic Church, in response to the growing influence and power of modernism, secularism and materialism, formed the First Vatican Council in the late 19th century to deal with such problems and confirm ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
