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Hans Wolter
Hans Wolter (11 May 1911 in Dramburg – 17 August 1978 in Marburg) was a German physicist who designed an aplanatic system of grazing incidence mirrors that satisfied the Abbe sine condition (i.e. free of both spherical aberration and coma). Wolter showed such a system could be produced using a combination of a paraboloid with either a hyperboloid or ellipsoid secondary. The three simplest designs are outlined and are known as Wolter telescope A Wolter telescope is a telescope for X-rays that only uses grazing incidence optics – mirrors that reflect X-rays at very shallow angles. Problems with conventional telescope designs Conventional telescope designs require reflection or refract ...s of types I, II and III. References External links X-ray Imaging Systems {{DEFAULTSORT:Wolter, Hans 20th-century German physicists 1911 births 1978 deaths People from Drawsko Pomorskie People from the Province of Pomerania ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dramburg
Drawsko Pomorskie (until 1948 pl, Drawsko; formerly german: Dramburg) is a town in Drawsko County in West Pomeranian Voivodeship in northwestern Poland, the administrative seat of Drawsko County and the urban-rural commune of Gmina Drawsko Pomorskie. As of December 2021, the town has a population of 11,292. It is home to the Drawsko Training Ground, one of the largest training areas in Poland. Geography Located in the southeast of West Pomeranian Voivodeship (since 1999) in the Pomerania region, Drawsko is situated within the Pomeranian Lakeland, the western spur of the Baltic Uplands. The town lies on the headwater of the Drawa River, a right tributary of the Noteć, west of an expansive woodland with the protected area of the Drawsko Landscape Park. The regional capital Szczecin is about to the west. A large training area south of the town is frequently used in NATO exercises. History Medieval Poland From the 7th century onwards Slavic tribes settled along the shor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marburg
Marburg ( or ) is a university town in the German federal state (''Bundesland'') of Hesse, capital of the Marburg-Biedenkopf district (''Landkreis''). The town area spreads along the valley of the river Lahn and has a population of approximately 76,000. Having been awarded town privileges in 1222, Marburg served as capital of the landgraviate of Hessen-Marburg during periods of the fifteenth to seventeenth centuries. The University of Marburg was founded in 1527 and dominates the public life in the town to this day. Marburg is a historic centre of the pharmaceutical industry in Germany, and there is a plant in the town (by BioNTech) to produce vaccines to tackle Covid-19. History Founding and early history Like many settlements, Marburg developed at the crossroads of two important early medieval highways: the trade route linking Cologne and Prague and the trade route from the North Sea to the Alps and on to Italy, the former crossing the river Lahn here. A first mention o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle Of Incidence (optics)
The angle of incidence, in geometric optics, is the angle between a ray incident on a surface and the line perpendicular (at 90 degree angle) to the surface at the point of incidence, called the normal. The ray can be formed by any waves, such as optical, acoustic, microwave, and X-ray. In the figure below, the line representing a ray makes an angle θ with the normal (dotted line). The angle of incidence at which light is first totally internally reflected is known as the critical angle. The angle of reflection and angle of refraction are other angles related to beams. In computer graphics and geography, the angle of incidence is also known as the illumination angle of a surface with a light source, such as the Earth's surface and the Sun. It can also be equivalently described as the angle between the tangent plane of the surface and another plane at right angles to the light rays. This means that the illumination angle of a certain point on Earth's surface is 0° if the Sun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. It was formulated by Ernst Abbe in the context of microscopes. The Abbe sine condition says that the sine of the object-space angle \alpha_o should be proportional to the sine of the image space angle \alpha_i Furthermore, the ratio equals the magnification of the system. In mathematical terms this is: :\frac = \frac = , M, where the variables (\alpha_o, \beta_o) are the angles (relative to the optic axis) of any two rays as they leave the object, and (\alpha_i, \beta_i) are the angles of the same rays where they reach the image plane (say, the film plane of a camera). For example, (\alpha_o, \alpha_i) might represent a paraxial ray (i.e., a ray nearly parallel with the optic axis), and (\beta_o, \beta_i) might represent a marginal ray (i.e., a ray with the largest angle admitted by the system apert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spherical Aberration
In optics, spherical aberration (SA) is a type of optical aberration, aberration found in optical systems that have elements with spherical surfaces. Lens (optics), Lenses and curved mirrors are prime examples, because this shape is easier to manufacture. Light rays that strike a spherical surface off-centre are refraction, refracted or reflection (physics), reflected more or less than those that strike close to the centre. This deviation reduces the quality of images produced by optical systems. Overview A spherical lens has an Optical aberration#Aberration of elements, i.e. smallest objects at right angles to the axis, aplanatic point (i.e., no spherical aberration) only at a radius that equals the radius of the sphere divided by the index of refraction of the lens material. A typical value of refractive index for crown glass is 1.5 (see List of refractive indices, list), which indicates that only about 43% of the area (67% of diameter) of a spherical lens is useful. It is o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coma (optics)
In optics (especially telescopes), 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. Overview Coma is an inherent property of telescopes using parabolic mirrors. Unlike a spherical mirror, a bundle of parallel rays parallel to the optical axis will be perfectly focused to a point (the mirror is free of spherical aberration), no matter where they strike the mirror. However, this is only true if the rays are parallel to the axis of the parabola. When the incoming rays strike the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraboloid
In geometry, a paraboloid is a quadric surface that has exactly one axis of symmetry and no center of symmetry. The term "paraboloid" is derived from parabola, which refers to a conic section that has a similar property of symmetry. Every plane section of a paraboloid by a plane parallel to the axis of symmetry is a parabola. The paraboloid is hyperbolic if every other plane section is either a hyperbola, or two crossing lines (in the case of a section by a tangent plane). The paraboloid is elliptic if every other nonempty plane section is either an ellipse, or a single point (in the case of a section by a tangent plane). A paraboloid is either elliptic or hyperbolic. Equivalently, a paraboloid may be defined as a quadric surface that is not a cylinder, and has an implicit equation whose part of degree two may be factored over the complex numbers into two different linear factors. The paraboloid is hyperbolic if the factors are real; elliptic if the factors are complex conjugate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperboloid
In geometry, a hyperboloid of revolution, sometimes called a circular hyperboloid, is the surface generated by rotating a hyperbola around one of its principal axes. A hyperboloid is the surface obtained from a hyperboloid of revolution by deforming it by means of directional scalings, or more generally, of an affine transformation. A hyperboloid is a quadric surface, that is, a surface defined as the zero set of a polynomial of degree two in three variables. Among quadric surfaces, a hyperboloid is characterized by not being a cone or a cylinder, having a center of symmetry, and intersecting many planes into hyperbolas. A hyperboloid has three pairwise perpendicular axes of symmetry, and three pairwise perpendicular planes of symmetry. Given a hyperboloid, one can choose a Cartesian coordinate system such that the hyperboloid is defined by one of the following equations: : + - = 1, or : + - = -1. The coordinate axes are axes of symmetry of the hyperboloid and the ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellipsoid
An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the zero set of a polynomial of degree two in three variables. Among quadric surfaces, an ellipsoid is characterized by either of the two following properties. Every planar cross section is either an ellipse, or is empty, or is reduced to a single point (this explains the name, meaning "ellipse-like"). It is bounded, which means that it may be enclosed in a sufficiently large sphere. An ellipsoid has three pairwise perpendicular axes of symmetry which intersect at a center of symmetry, called the center of the ellipsoid. The line segments that are delimited on the axes of symmetry by the ellipsoid are called the ''principal axes'', or simply axes of the ellipsoid. If the three axes have different lengths, the figure is a triaxial ellipsoid (r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolter Telescope
A Wolter telescope is a telescope for X-rays that only uses grazing incidence optics – mirrors that reflect X-rays at very shallow angles. Problems with conventional telescope designs Conventional telescope designs require reflection or refraction in a manner that does not work well for X-rays. Visible light optical systems use either lenses or mirrors aligned for nearly normal incidence – that is, the light waves travel nearly perpendicular to the reflecting or refracting surface. Conventional mirror telescopes work poorly with X-rays, since X-rays that strike mirror surfaces nearly perpendicularly are either transmitted or absorbed – not reflected. Lenses for visible light are made of transparent materials with an index of refraction substantially different from 1, but all known X-ray-transparent materials have index of refraction essentially the same as 1, so X-ray lenses are not practical. X-ray mirror telescope design X-ray mirrors can be built, but only if the angle f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1911 Births
A notable ongoing event was the race for the South Pole. Events January * January 1 – A decade after federation, the Northern Territory and the Australian Capital Territory are added to the Commonwealth of Australia. * January 3 ** 1911 Kebin earthquake: An earthquake of 7.7 moment magnitude strikes near Almaty in Russian Turkestan, killing 450 or more people. ** Siege of Sidney Street in London: Two Latvian anarchists die, after a seven-hour siege against a combined police and military force. Home Secretary Winston Churchill arrives to oversee events. * January 5 – Egypt's Zamalek SC is founded as a general sports and Association football club by Belgian lawyer George Merzbach as Qasr El Nile Club. * January 14 – Roald Amundsen's South Pole expedition makes landfall, on the eastern edge of the Ross Ice Shelf. * January 18 – Eugene B. Ely lands on the deck of the USS ''Pennsylvania'' stationed in San Francisco harbor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
