Lahnsteinite is biaxial negative, no dispersion of optical axes was observed.
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Crystal optics describes light propagation in these media. An "axis of anisotropy" is defined as the axis along which isotropy is broken (or an axis of symmetry, such as normal to crystalline layers). Some materials can have multiple such optical axes.
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This occurs because the ommatidia that one observes "head-on" (along their optical axes) absorb the incident light, while those to one side reflect it. The pseudopupil therefore reveals which ommatidia are aligned with the axis along which the observer is viewing.
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A Glan–Taylor prism reflects s-polarized light at an internal air-gap, transmitting only the p-polarized component. The optical axes are vertical in the plane of the diagram. A Glan–Taylor prism is a type of prism which is used as a polarizer or polarizing beam splitter. It is one of the most common types of modern polarizing prism.
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The primary sensors consisted of a very high resolution radiometer (VHRR), a vertical temperature profile radiometer (VTPR), and a scanning radiometer (SR). The VHRR, VTPR, and SR were mounted on the satellite baseplate with their optical axes directed vertically earthward. The nearly cubical spacecraft measured . The satellite was equipped with three curved solar panels that were folded during launch and deployed after orbit was achieved.
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Anisotropic crystals will have optical properties that vary with the direction of light. The direction of the electric field determines the polarization of light, and crystals will respond in different ways if this angle is changed. These kinds of crystals have one or two optical axes. If absorption of light varies with the angle relative to the optical axis in a crystal then pleochroism results.
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1 Edition. Focal Press. p. 199 Because the cameras in this set-up aren’t physically in their way, the distance between the optical axes of the cameras can be smaller than the size of the lenses and even down to zero. Shots with small interaxial distances are possible, which is necessary for shooting in a classical movie style with close-up and detail shots.
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Cheshire eyepiece, combined with a sight tube and crosshairs. A Cheshire eyepiece or Cheshire collimator is a simple tool that helps aligning the optical axes of the mirrors or lenses of a telescope, a process called collimation. It consists of a peephole to be inserted into the focuser in place of the eyepiece. Through a lateral opening, ambient light falls on the brightly painted oblique back of the peephole.
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Although there is no axis of symmetry, there are two optical axes or binormals which are defined as directions along which light may propagate without birefringence, i.e., directions along which the wavelength is independent of polarization. For this reason, birefringent materials with three distinct refractive indices are called biaxial. Additionally, there are two distinct axes known as optical ray axes or biradials along which the group velocity of the light is independent of polarization.
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The least complex way to take pictures or shoot film in 3D is having two cameras mounted side-by-side. They are aligned parallel to each other, or can be angulated so that their optical axes meet at a chosen distance. In some systems the cameras are fixed to the rig body and can not be moved. More professional side-by-side-rigs, however, offer the possibility to change the interaxial distance easily.
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It was first described by Archard and Taylor in 1948. The prism is made of two right-angled prisms of calcite (or sometimes other birefringent materials) separated on their long faces with an air gap. The optical axes of the calcite crystals are aligned parallel to the plane of reflection. Total internal reflection of s-polarized light at the air gap ensures that only p-polarized light is transmitted by the device.
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The light passing through the mineral will therefore have different colors when it is viewed from different angles, making the stone seem to be of different colors. Tetragonal, trigonal, and hexagonal minerals can only show two colors and are called dichroic. Orthorhombic, monoclinic, and triclinic crystals can show three and are trichroic. For example, hypersthene, which has two optical axes, can have a red, yellow, or blue appearance when oriented in three different ways in three-dimensional space.
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This occurs because the ommatidia which one observes "head-on" (along their optical axes) absorb the incident light, while those to one side reflect it. There are some exceptions from the types mentioned above. Some insects have a so-called single lens compound eye, a transitional type which is something between a superposition type of the multi-lens compound eye and the single lens eye found in animals with simple eyes. Then there is the mysid shrimp, Dioptromysis paucispinosa.
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A Glan–Thompson prism consists of two right-angled calcite prisms that are cemented together by their long faces. The optical axes of the calcite crystals are parallel and aligned perpendicular to the plane of reflection. Birefringence splits light entering the prism into two rays, experiencing different refractive indices; the p-polarized ordinary ray is totally internally reflected from the calcite–cement interface, leaving the s-polarized extraordinary ray to be transmitted. The prism can therefore be used as a polarizing beam splitter.
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The photon of an incident laser pulse (pump) is, by a nonlinear optical crystal, divided into two lower-energy photons. The wavelengths of the signal and the idler are determined by the phase matching condition, which is changed, e.g. by temperature or, in bulk optics, by the angle between the incident pump laser ray and the optical axes of the crystal. The wavelengths of the signal and the idler photons can, therefore, be tuned by changing the phase matching condition.
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Each of the three axes were stabilized and the optical axes of the three scientific instruments were coaligned. The entrance apertures of the scientific instruments were all located on one face of the central body. Once in orbit the flaps which cover the entrances to the ME and LEIT were swung open to act as thermal and stray-light shields for the telescopes and star trackers, respectively. The orbit of Exosat was different from any previous X-ray astronomy satellite.
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Untreated tanzanite is a trichroic gemstone, meaning that light that enters this anisotropic crystal gets refracted on different paths, with different color absorption on each of the three optical axes. As a result of this phenomenon, a multitude of colors have been observed in various specimens: shades of purple, violet, indigo, blue, cyan, green, yellow, orange, red and brown. After heating, tanzanite becomes dichroic. The dichroic colors range from violet through bluish-violet to indigo and violetish-blue to blue.
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It also carried a low-resolution flat plate radiometer, a solar proton monitor, and two scanning radiometers that not only could measure emitted IR radiation but could also serve as a backup system for the APT and AVCS cameras. The nearly cubical spacecraft measured . The TV cameras and infrared sensors were mounted on the satellite baseplate with their optical axes directed vertically earthward. The satellite was equipped with three curved solar panels that were folded during launch and were to be deployed after orbit was achieved.
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Fossilised exocones (the cone-shaped lens-cylinders which make up the compound eye) of J. rhenaniae. The cheliceral morphology and visual acuity of the pterygotid eurypterids separates them into distinct ecological groups. The primary method for determining visual acuity in arthropods is by determining the number of lenses in their compound eyes and the interommatidial angle (IOA), which is the angle between the optical axes of adjacent lenses. The IOA is especially important as it can be used to distinguish different ecological roles in arthropods, being low in modern active arthropod predators.
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The sun- synchronous spacecraft was also capable of supplying global atmospheric temperature soundings and very high resolution infrared cloudcover data for selected areas in either a direct readout or a tape-recorder mode. A secondary objective was to obtain global solar-proton flux data on a real-time daily basis. The primary sensors consisted of Very High Resolution Radiometer (VHRR), a Vertical Temperature Profile Radiometer (VTPR), and a Scanning Radiometer (SR). The VHRR, VTPR, and SR were mounted on the satellite baseplate with their optical axes directed vertically earthward.
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The purpose of XP is provide an on-orbit cross-calibration for the X123: the sum of the X123 spectrum should be approximately equal to the XP measurement. SPS is a fine sun sensor with 2.4 arcsec precision that consists of a planar quad-diode observing visible light, whose purpose is to provide fine knowledge of the solar position with respect to the X123 and XP optical axes to correct for any off-axis signal attenuation. All instruments were calibrated at the National Institute of Standards and Technology's Synchrotron Ultraviolet Radiation Facility (SURF III).
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The axes are designated X, Y, and Z for direction, and alpha, beta, and gamma in magnitude of the refractive index. These axes can be determined from the appearance of a crystal in a conoscopic interference pattern. Where there are two optical axes, the acute bisectrix of the axes gives Z for positive minerals and X for negative minerals and the obtuse bisectrix gives the alternative axis (X or Z). Perpendicular to these is the Y axis. The color is measured with the polarization parallel to each direction.
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For technological applications the divergent beam has to be focused, which is realized by the magnetic field of a coil, the magnetic focusing lens. For proper functioning of the electron gun, it is necessary that the beam be perfectly adjusted with respect to the optical axes of the accelerating electrical lens and the magnetic focusing lens. This can be done by applying a magnetic field of some specific radial direction and strength perpendicular to the optical axis before the focusing lens. This is usually realized by a simple correction system consisting of two pairs of coils.
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IPD data are used in the design of such systems to specify the range of lateral adjustment of the exit optics or eyepieces. IPD is also used to describe the distance between the exit pupils or optical axes of a binocular optical system. The distinction with IPD is the importance of anthropometric databases and the design of binocular viewing devices with an IPD adjustment that will fit a targeted population of users. Because instruments such as binoculars and microscopes can be used by different people, the distance between the eye pieces is usually made adjustable to account for IPD.
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The trapping of micrometer-sized particles by two laser beams was first demonstrated by Arthur Ashkin in 1970, before he developed the single-beam trap now known as optical tweezers. An advantage of the single-beam design is that no two laser beams need to be exactly adjusted to make their optical axes match. From the late 1980s on, optical tweezers have been used to trap and hold biological dielectrica, such as cells or viruses. However, in order to ensure trap stability, the single beam must be highly focused, with the particle trapped close to the focus point.
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Restoration depicting Pterygotus hunting upright The cheliceral morphology and visual acuity of the pterygotid eurypterids separates them into distinct ecological groups. The primary method for determining visual acuity in arthropods is by determining the number of lenses in their compound eyes and the interommatidial angle (shortened as IOA and referring to the angle between the optical axes of the adjacent lenses). The IOA is especially important as it can be used to distinguish different ecological roles in arthropods, being low in modern active arthropod predators. Both Pterygotus anglicus and Jaekelopterus rhenaniae had a very high visual acuity, which researchers could determine by observing a low IOA and a large number of lenses in their compound eyes.
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In 1839, Alexandre Edmond Becquerel (1820–1891) had discovered that illumination of one of two metal plates in a dilute acid changed the electromotive force (EMF). Adams, however, had a wide area of interest, chief among these was light and magnetism. Light was the focus of Adams’ research, which began in 1871, in which he studied the effects of polarization. In order to study the effects of polarization on various substances like selenium and tellurium, Adams developed a new variant of the polariscope. In doing this, he was able to research “the optical axes of biaxial crystals.” In 1876, Adams and Richard Evans Day discovered that illuminating a junction between selenium and platinum has a photovoltaic effect.
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The primary method for determining visual acuity in arthropods is by determining the number of lenses in their compound eyes and the interommatidial angle (shortened as IOA and referring to the angle between the optical axes of the adjacent lenses). The IOA is especially important as it can be used to distinguish different ecological roles in arthropods, being low in modern active arthropod predators. The vision of Erettopterus was similar to that of the more basal pterygotoid Slimonia and more acute than the more derived Acutiramus though was not as acute as the vision of apex predators Jaekelopterus and Pterygotus or modern active predatory arthropods. Additionally, the large chelicerae of Erettopterus suggest that it was a generalized feeder and not a highly specialized predator and that it used its chelicerae (frontal appendages) to grasp.
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