Diagram of three types of reflector sights. The top uses a collimating lens (CL) and a beam splitter (B) to create a virtual image at infinity (V) of a reticle (R). The bottom two use half silvered curved mirrors (CM) as the collimating optics Reflector sights work by using a lens or an image-forming curved mirror with a luminous or reflective overlay image or reticle at its focus, creating an optical collimator that produces a virtual image of that reticle. The image is reflected off some form of angled beam splitter or the partially silvered collimating curved mirror itself so that the observer (looking through the beam splitter or mirror) will see the image at the focus of the collimating optics superimposed in the sight's field of view in focus at ranges up to infinity.
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Although some monochromator designs do use focusing gratings that do not need separate collimators, most use collimating mirrors. Reflective optics are preferred because they do not introduce dispersive effects of their own.
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Diagram of three types of reflector sights that produce collimated reticles. The top uses a collimating lens (CL) and a beam splitter (B) to create a virtual image at infinity (V) of a reticle (R). The bottom two use half silvered curved mirrors (CM) as the collimating optics with the reticle off-set or between the mirror and the observer. Collimated reticles are produced by non-magnifying optical devices such as reflector sights (often called reflex sights) that give the viewer an image of the reticle superimposed over the field of view, and blind collimator sights that are used with both eyes.
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The microscopes on the limb are then read off, and thus the apparent zenith distance of the collimating point, intersection of the wires, is found. The collimator is then transferred to the other (south) side of the circle, and a corresponding observation made without reversing the circle, but merely by the motion of the telescope on the limb. The difference of the two zenith distances so read off is double the error of the zenith or horizontal point of the graduation, and their semi-sum is the true zenith distance of the collimating point, or the co-inclination of the axis of the collimating telescope to the horizon. By the experiments detailed in captain Kater's paper, read before the Royal Society in 1825, it appears that the error to be feared in the determination of the horizontal point by this instrument, can rarely amount to half a second, if a mean of four or five observations be taken.
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For interference lithography to be successful, coherence requirements must be met. First, a spatially coherent light source must be used. This is effectively a point light source in combination with a collimating lens. A laser or synchrotron beam are also often used directly without additional collimation.
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Eye movement perpendicular to the device's optical axis will make the reticle image move in exact relationship to eye position in the cylindrical column of light created by the collimating optics.American rifleman: Volume 93, National Rifle Association of America - THE REFLECTOR SIGHT By JOHN B. BUTLER, page 31 A common type (used in applications such as aircraft gun sights) uses a collimating lens and a beam splitter. This type tends to be bulky since it requires at least two optical components, the lens and the beam splitter/glass plate. The reticle collimation optics are situated at 90° to the optical path making lighting difficult, usually needing additional electric illumination, condensing lenses, etc.
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Beam spots with diameter down to about two micrometres can be obtained by collimating the beam with pinhole apertures or with a drawn capillary. Sub- micrometre beam spot sizes have been achieved by focusing the beam using various combinations of electrostatic or magnetic lenses. Both methods are used at present.
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An example of an optical collimating lens.A perfect parabolic mirror will bring parallel rays to a focus at a single point. Conversely, a point source at the focus of a parabolic mirror will produce a beam of collimated light creating a Collimator. Since the source needs to be small, such an optical system cannot produce much optical power.
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The limits on focusing or collimating a laser beam are very similar to the limits on imaging with a microscope or telescope. The only difference is that laser beams are typically soft-edged beams. This non-uniformity in light distribution leads to a coefficient slightly different from the 1.22 value familiar in imaging. But the scaling is exactly the same.
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In practice, Luneburg lenses are normally layered structures of discrete concentric shells, each of a different refractive index. These shells form a stepped refractive index profile that differs slightly from Luneburg's solution. This kind of lens is usually employed for microwave frequencies, especially to construct efficient microwave antennas and radar calibration standards. Cylindrical analogues of the Luneburg lens are also used for collimating light from laser diodes.
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In a Nature article, Bobrowsky et al. described how the Hubble observations revealed a 17th-magnitude companion to the Stingray's 15th-magnitude central star. The image of the Stingray Nebula shown here shows how the outer shells of gas are collimating the continuing outflow of gas from the central star—an important observation, as the process of how these outflows become collimated has not been well understood.
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Small molded aspheres are often used for collimating diode lasers. Aspheric lenses are also sometimes used for eyeglasses. Aspheric eyeglass lenses allow for crisper vision than standard "best form" lenses, mostly when looking in other directions than the lens optical center. Moreover, the reduction of the magnification effect of a lens may help with prescriptions that have different powers in the 2 eyes (anisometropia).
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The illuminated reticle was eventually replaced by a video screen at the focus of the collimating optics that not only gave a sighting point and information from a lead-finding computer and radar, but also various aircraft indicators (such as an artificial horizon, compass, altitude and airspeed indicators), facilitating the visual tracking of targets or the transition from instrument to visual methods during landings.
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Spectrophotometry: Quantitative measurement of transmittance based on wavelength. It is important in a number of biomedical fields ranging from the measurement of a solute in a sample to determining enzyme kinetics for a given substrate-enzyme pair. Spectrophotometry requires multiple wavelengths for a wide variety of samples. Therefore, an arc lamp is used to generate multiple wavelengths for collimating mirrors and diffraction gratings to generate collimated light at narrow bandwidths.
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In it, Cary and Beckman compared designs for a modified self- collimating quartz Fery prism, a mirror-collimated quartz Littrow prism, and various gratings. The Littrow prism was a half-prism, which had a mirrored face. Use of a tungsten light source with the quartz Littrow prism as a monochromator was reported to minimize light scattering within the instrument. The Model D was the first model to enter actual production.
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Horrified that Chris would just impulsively blurt that out, Emily denied actually being in love with Chris but confessed, to a shocked Hal, that in her loneliness, she flirted with Chris, collimating in only a few kisses. After hearing her tearful explanation, Hal realized that he hadn't been fair to Emily and forgave her. Unfortunately, the Munson marriage would continue to deteriorate. A year later, after an argument, Emily moved and then had an affair with Paul.
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A Petoscope is an optoelectronic device for detecting small, distant objects such as flying aircraft. The design, as described in 1936,"Twin 'Eyes' Scan Sky for Planes", Popular Mechanics, Vol. 66, No. 2, , Hearst Magazines, August 1936 consisted of an instrument with two parallel light paths. In each path was a collimating objective lens, a screen marked with many small, alternating opaque and transparent squares in a chequerboard pattern, and a second concentrating lens focused on a photocell.
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The most common optical system uses spherical collimators and thus contains optical aberrations that curve the field where the slit images come to focus, so that slits are sometimes curved instead of simply straight, to approximate the curvature of the image. This allows taller slits to be used, gathering more light, while still achieving high spectral resolution. Some designs take another approach and use toroidal collimating mirrors to correct the curvature instead, allowing higher straight slits without sacrificing resolution.
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Infographic of JWST instruments and their observation ranges of light by wavelength NIRCam has two complete optical systems for redundancy. The two sides can operate at the same time, and view two separate patches of sky; the two sides are called side A and side B. The lenses used in the internal optics are triplet refractors. The lens materials are lithium fluoride (LiF), a barium fluoride (BaF2) and zinc selenide (ZnSe). The triplet lenses are collimating optics.
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1901 diagram of a version of Howard Grubb's collimating reflector sight designed to make a compact version suitable for firearms and small devices. Ambient lighting of the reticle was improved by placing it facing up and bouncing it off a relay mirror then off a concave collimating mirror The idea of a reflector sight originated in 1900 with Irish optical designer and telescope maker Howard Grubb in patent No.12108. Grubb conceived of his "Gun Sight for large and small Ordnance" as a better alternative to the difficult to use iron sight while avoiding the telescopic sight's limited field of view, greater apparent target speed, parallax errors, and the danger of keeping the eye against an eye stop. In the 1901 the Scientific Transactions of the Royal Dublin Society he described his invention as: Prototype of the Grubb reflector sight attached to a rifle It was noted soon after its invention that the sight could be a good alternative to iron sights and also had uses in surveying and measuring equipment.
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While earlier X-ray telescopes were using simple collimating techniques (e.g. rotating collimators, wire collimators), the technology most currently used on present days employs coded aperture masks. This technique uses a flat aperture patterned grille in front of the detector. This design results less sensitive than focusing optics and imaging quality and identification of source position is much poorer, however it offers a larger field of view and can be employed at higher energies, where grazing incidence optics become ineffective.
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Laser welding not only requires high laser power but also a high quality beam to obtain the desired "deep-weld effect". The resulting higher quality of beam can be exploited either to obtain a smaller focus diameter or a larger focal distance. A variety of laser types are used for this process, in particular Nd:YAG where the laser light can be transmitted via a water-cooled glass fiber. The beam is projected onto the workpiece by collimating and focusing optics.
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The weapon is coated with a rust-resistant coating which doubles as a dry lubricant. Owing to a wide variety of muzzle devices (including silencers, heat shields, and even rifle grenades), the weapon can be used to fire non-lethal and explosive projectiles by the means of blank cartridge, as well as normal ammunition. The BXP also features an underfolding buttstock, made from stamped steel. The standard sights are of open type, but the BXP can be equipped with laser aiming modules and collimating sights.
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X-ray lithography originated as a candidate for next-generation lithography for the semiconductor industry, with batches of microprocessors successfully produced. Having short wavelengths (below 1 nm), X-rays overcome the diffraction limits of optical lithography, allowing smaller feature sizes. If the X-ray source isn't collimated, as with a synchrotron radiation, elementary collimating mirrors or diffractive lenses are used in the place of the refractive lenses used in optics. The X-rays illuminate a mask placed in proximity of a resist-coated wafer.
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The requirement of collimated light in classical schlieren is often a substantial practical barrier for constructing large systems due to the need for the collimating optic to be the same size as the field of view. Focusing schlieren systems can use compact optics with a large background illumination pattern, which is particularly easy to produce with a projection system. For systems with large demagnification, the illumination pattern needs to be around twice larger than the field of view to allow defocusing of the background pattern.
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The spectrograph has been designed and constructed for UV echelle line profile measurements with long-slit imaging. The Ebert-Fastie configuration employed in the design of the spectrograph has many characteristics well suited to the science needs of this mission. Symmetric off-axis reflections from a single collimating mirror are employed to remove aberrations: the spatial resolution is limited by the telescope and the spectral resolution by the grating and aperture characteristics. Use of a paraboloidal collimator, has produced 2 arc sec image quality with minimal astigmatism along the central 2–3 arc min.
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Recent efforts have avoided focussing elements and instead are directly collimating a beam with a pinhole. The lack of atom optics means that the beam will be significantly larger than in an electron microscope. The first published demonstration of a two dimensional image formed by helium reflecting from the surface was by Witham and Sánchez who used a pinhole to form the helium beam. A small pinhole is placed very close to a sample and the helium scattered into a large solid angle is fed to a detector.
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Laser light from gas or crystal lasers is highly collimated because it is formed in an optical cavity between two parallel mirrors which constrain the light to a path perpendicular to the surfaces of the mirrors. In practice, gas lasers can use concave mirrors, flat mirrors, or a combination of both. The divergence of high-quality laser beams is commonly less than 1 milliradian (3.4 arcmin), and can be much less for large-diameter beams. Laser diodes emit less-collimated light due to their short cavity, and therefore higher collimation requires a collimating lens.
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The way in which the beam profile of a laser beam changes as it propagates is determined by diffraction. When the entire emitted beam has a planar, spatially coherent wave front, it approximates Gaussian beam profile and has the lowest divergence for a given diameter. The smaller the output beam, the quicker it diverges. It is possible to reduce the divergence of a laser beam by first expanding it with one convex lens, and then collimating it with a second convex lens whose focal point is coincident with that of the first lens.
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International X-ray Observatory concept An X-ray telescope (XRT) is a telescope that is designed to observe remote objects in the X-ray spectrum. In order to get above the Earth's atmosphere, which is opaque to X-rays, X-ray telescopes must be mounted on high altitude rockets, balloons or artificial satellites. The basic elements of the telescope are the optics (focusing or collimating), that collects the radiation entering the telescope, and the detector, on which the radiation is collected and measured. A variety of different designs and technologies have been used for these elements.
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Reflex sights such as the Telrad (pictured) are popular alternatives to traditional finderscopes, and are often used in conjunction with them. Another type of finder commonly found on amateur telescopes is known as a reflector (reflex) sight. This non-magnifying sight (technically not a "scope") uses a type of beam splitter to "reflect" a reticle generated by collimating optics into the users field of view. The view of the sky seen through the sight is just what can be seen with the naked eye with an illuminated crosshair or dot seeming to float in space at infinity.
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The result is that light traveling an equal optical path length in the test and reference beams produces a white light fringe of constructive interference. The heart of the Fabry–Pérot interferometer is a pair of partially silvered glass optical flats spaced several millimeters to centimeters apart with the silvered surfaces facing each other. (Alternatively, a Fabry–Pérot etalon uses a transparent plate with two parallel reflecting surfaces.) As with the Fizeau interferometer, the flats are slightly beveled. In a typical system, illumination is provided by a diffuse source set at the focal plane of a collimating lens.
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A more compact type replaces the lens/beam splitter configuration with a half silvered or dichroic curved collimating mirror set at an angle that performs both tasks of focusing and combining the image of an offset reticle. This type is most often seen as the red dot type used on small arms. It is also possible to place the reticle between the viewer and the curved mirror at the mirror's focus. The reticle itself is too close to the eye to be in focus but the curved mirror presents the viewer with an image of the reticle at infinity.
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Schlieren imaging system setup: linear lens- based configuration The optical setup of a schlieren imaging system may comprise the following main sections: Parallel beam, focusing element, stop (sharp edge) and a camera. The parallel beam may be achieved by a point-like light source (a laser focused into a pinhole is sometimes used) placed in the focal point of a collimating optical element (lens or mirror). The focusing element may be a lens or a mirror. The optical stop may be realized by a razor placed horizontally or vertically in the focal point of the focusing element, carefully positioned to block the light spot image on its edge.
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HUD mounted in a PZL TS-11 Iskra jet trainer aircraft with a glass plate combiner and a convex collimating lens just below it A typical HUD contains three primary components: a projector unit, a combiner, and a video generation computer. The projection unit in a typical HUD is an optical collimator setup: a convex lens or concave mirror with a cathode ray tube, light emitting diode display, or liquid crystal display at its focus. This setup (a design that has been around since the invention of the reflector sight in 1900) produces an image where the light is collimated, i.e. the focal point is perceived to be at infinity.
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Since the collimated image produced by the sight is only truly parallax free at infinity, the sight has an error circle equal to the diameter of the collimating optics for any target at a finite distance. Depending on the eye position behind the sight and the closeness of the target this induces some aiming error. For larger targets at a distance (given the non-magnifying, quick target acquisitions nature of the sight) this aiming error is considered trivial. On small arms aimed at close targets this is compensated for by keeping the reticle in the middle of the optical window (sighting down its optical axis).
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View through Tasco ProPoint red dot sight (model PDP2ST) on a Ruger 10/22. Made in Japan for Tasco, the ProPoint 2 was one of the first red dot sight models to become widely popular. A red dot sight is a common classification for a type of non-magnifying reflector (or reflex) sight for firearms, and other devices that require aiming, that gives the user an aimpoint in the form of an illuminated red dot. A standard design uses a red light-emitting diode (LED) at the focus of collimating optics which generates a dot style illuminated reticle that stays in alignment with the weapon the sight is attached to regardless of eye position (nearly parallax free).
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1901 diagram of one of Howard Grubb's collimating reflector sights. This version was designed to make it compact for use on firearms and other equipment. In 1900 Grubb invented the reflector or "reflex" sight,John Murray, Science progress, Volume 76, page 498Nature, Volume 65, January 9,1902, edited by Sir Norman Lockyer, page 226 a non-magnifying optical sight that uses a collimator to allow the viewer looking through the sight to see an illuminated image of a reticle or other pattern in front of them that stays in alignment with the device the sight is attached to (parallax free). This type of sight has come to be used on all kinds of weapons from small firearms to fighter aircraft.
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More complex reticle patterns such as crosshairs or concentric circles can be used but need more complex aberration free optics. Like other reflector sights, the collimated image of the red dot is truly parallax free only at infinity, with an error circle equal to the diameter of the collimating optics for any target at a finite distance.Encyclopedia of Bullseye Pistol This is compensated for by keeping the dot in the middle of the optical window (sighting down the sight's optical axis).Tony L. Jones, The police officer's guide to operating and surviving in low-light and no-light conditions, page 86 Some manufacturers modify the focus of the LED/optical collimator combination, making models with the optical collimator set to focus the dot at a finite distance.
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The term transit theodolite, or transit for short, refers to a type of theodolite where the telescope is short enough to rotate in a full circle on its horizontal axis as well as around its vertical axis. It features a vertical circle which is graduated through the full 360 degrees and a telescope that could "flip over" ("transit the scope"). By reversing the telescope and at the same time rotating the instrument through 180 degrees about the vertical axis, the instrument can be used in 'plate-left' or 'plate- right' modes ('plate' refers to the vertical protractor circle). By measuring the same horizontal and vertical angles in these two modes and then averaging the results, centering and collimating errors in the instrument can be eliminated.
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By observing the motion of an artificial star, located east or west of the center of the main instrument, and seen through this axis telescope and a small collimating telescope, as the main telescope was rotated, the shape of the pivots, and any wobble of the axis, could be determined.Bond, Bond and Winlock (1876), p. 27 Top view of a circle-reading microscope; from Norton (1867). Near each end of the axis, attached to the axis and turning with it, was a circle or wheel for measuring the angle of the telescope to the zenith or horizon. Generally of 1 to 3 feet or more in diameter, it was divided to 2 or 5 arcminutes, on a slip of silver set into the face of the circle near the circumference.
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Point- collimation instruments have pinholes that shape the X-ray beam to a small circular or elliptical spot that illuminates the sample. Thus the scattering is centro-symmetrically distributed around the primary X-ray beam and the scattering pattern in the detection plane consists of circles around the primary beam. Owing to the small illuminated sample volume and the wastefulness of the collimation process—only those photons are allowed to pass that happen to fly in the right direction—the scattered intensity is small and therefore the measurement time is in the order of hours or days in case of very weak scatterers. If focusing optics like bent mirrors or bent monochromator crystals or collimating and monochromating optics like multilayers are used, measurement time can be greatly reduced.
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Diagram of a typical "red dot" sight using a collimating mirror with a light-emitting diode at its focus that creates a virtual "dot" image at infinity The typical configuration for a red dot sight is a tilted spherical mirror reflector with a red light-emitting diode (LED) at its off axis focus. The mirror has a partially silvered multilayer dielectric dichroic coating designed to reflect just the red spectrum allowing it to pass through most other light. The LED used is usually deep red 670 nanometre wavelength since they are very bright, are high contrast against a green scene, and work well with a dichroic coating since they are near one end of the visible spectrum. The size of the dot generated by the LED is controlled by an aperture hole in front of it made from metal or coated glass.
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Adding further optics to a Nasmyth-style telescope to deliver the light (usually through the declination axis) to a fixed focus point that does not move as the telescope is reoriented gives a coudé focus (from the French word for elbow). The coudé focus gives a narrower field of view than a Nasmyth focus and is used with very heavy instruments that do not need a wide field of view. One such application is high-resolution spectrographs that have large collimating mirrors (ideally with the same diameter as the telescope's primary mirror) and very long focal lengths. Such instruments could not withstand being moved, and adding mirrors to the light path to form a coudé train, diverting the light to a fixed position to such an instrument housed on or below the observing floor (and usually built as an unmoving integral part of the observatory building) was the only option.
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By conducting sets of measurements with the plane of the zenith sector first facing east and then west, he successfully avoided any systematic errors arising from collimating the sector. To determine the deflection due to the mountain, it was necessary to account for the curvature of the Earth: an observer moving north or south will see the local zenith shift by the same angle as any change in geodetic latitude. After accounting for observational effects such as precession, aberration of light and nutation, Maskelyne showed that the difference between the locally determined zenith for observers north and south of Schiehallion was 54.6 arc seconds. Once the surveying team had provided a difference of 42.94″ latitude between the two stations, he was able to subtract this, and after rounding to the accuracy of his observations, announce that the sum of the north and south deflections was 11.6″.
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