Orienting the map with north at the top, Ricci defined geographic space by using a graticule, which traces longitudes, latitudes, and meridians onto the chart.
|
|
Most of Fortress' remaining assets in liquid markets are through a minority interest in Graticule Asset Management Asia, which managed $4.1 billion as of June 30.
|
|
After reflection by a mirror on the workpiece, the light returns through the Autocollimator and passes through the beam splitter, forming an image of the target graticule in the plane of an eyepiece graticule. The eyepiece graticule and the reflected image of the target graticule are viewed simultaneously through the eyepiece. The image of the target graticule is always seen in focus and at constant magnification in the eyepiece, regardless of the distance between the Autocollimator and the reflecting surface. However, at long working distances only a portion of the reflected target graticule may appear in the eyepiece, owing to the failure of obliquely returning rays to enter the Autocollimator.
|
|
Most oscilloscopes have a graticule as part of the visual display, to facilitate measurements. The graticule may be permanently marked inside the face of the CRT, or it may be a transparent external plate made of glass or acrylic plastic. An internal graticule eliminates parallax error, but cannot be changed to accommodate different types of measurements. Oscilloscopes commonly provide a means for the graticule to be illuminated from the side, which improves its visibility.
|
|
The 'equator', 'poles' (E and W) and 'meridians' of the rotated graticule are identified with the chosen central meridian, points on the equator 90 degrees east and west of the central meridian, and great circles through those points. Transverse mercator geometry The position of an arbitrary point (φ,λ) on the standard graticule can also be identified in terms of angles on the rotated graticule: φ′ (angle M′CP) is an effective latitude and −λ′ (angle M′CO) becomes an effective longitude. (The minus sign is necessary so that (φ′,λ′) are related to the rotated graticule in the same way that (φ,λ) are related to the standard graticule). The Cartesian (x′,y′) axes are related to the rotated graticule in the same way that the axes (x,y) axes are related to the standard graticule.
|
|
The front hemisphere of the Hammer retroazimuthal projection. 15° graticule; center point at 45°N, 90°W. The back hemisphere of the Hammer retroazimuthal projection. 15° graticule; center point at 45°N, 90°W.
|
|
Frequency can also be determined by measuring the waveform period and calculating its reciprocal. On old and lower-cost CRT oscilloscopes the graticule is a sheet of plastic, often with light-diffusing markings and concealed lamps at the edge of the graticule. The lamps had a brightness control. Higher-cost instruments have the graticule marked on the inside face of the CRT, to eliminate parallax errors; better ones also had adjustable edge illumination with diffusing markings.
|
|
The scale, spacing, etc., of the graticule can therefore be varied, and accuracy of readings may be improved.
|
|
This work was awarded the prestigious Bedford Prize by the British Occupational Hygiene Society. In 1977, Henry Walton and Dr Steve Beckett invented a microscope eyepiece graticule used for counting asbestos fibres.Walton WH, Beckett ST. (1977) A microscope eyepiece graticule for the evaluation of fibrous dusts. Ann Occup Hyg; 20: 19-23.
|
|
Transverse mercator graticules The figure on the left shows how a transverse cylinder is related to the conventional graticule on the sphere. It is tangential to some arbitrarily chosen meridian and its axis is perpendicular to that of the sphere. The x- and y-axes defined on the figure are related to the equator and central meridian exactly as they are for the normal projection. In the figure on the right a rotated graticule is related to the transverse cylinder in the same way that the normal cylinder is related to the standard graticule.
|
|
The vectorscope can be set up for 75% or 100% bars by adjusting the gain so that the color burst vector extends to the "75%" or "100%" marking on the graticule. The reference signal used for the vectorscope's display is the color burst that is transmitted before each line of video, which for NTSC is defined to have a phase of 180°, corresponding to the nine-o'clock position on the graticule. The actual color burst signal shows up on the vectorscope as a straight line pointing to the left from the center of the graticule. In the case of PAL, the color burst phase alternates between 135° and 225°, resulting in two vectors pointing in the half-past-ten and half-past-seven positions on the graticule, respectively.
|
|
A perspective view of the Earth showing how latitude (\phi) and longitude (\lambda) are defined on a spherical model. The graticule spacing is 10 degrees.
|
|
The waveform-mode graticule of these instruments is implemented with a silkscreen, whereas the vectorscope graticule (consisting only of bar targets, as this family did not support composite video) was drawn on the CRT by the electron beam. Modern instruments have graticules drawn using computer graphics, and both graticule and trace are rendered on an external VGA monitor or an internal VGA-compatible LCD display. Most modern waveform monitors include vectorscope functionality built in; and many allow the two modes to be displayed side-by-side. The combined device is typically referred to as a waveform monitor, and standalone vectorscopes are rapidly becoming obsolete.
|
|
A graticule is a piece that has lines for precise lengths etched into it. Graticules may be fitted into the eyepiece or they may be used on the measurement plane.
|
|
Adams hemisphere-in-a-square projection. 15° graticule. The Adams doubly periodic projection with Tissot's indicatrix of deformation. The Adams hemisphere-in-a-square is a conformal map projection for a hemisphere.
|
|
The world on an equidistant conic projection. 15° graticule, standard parallels of 20°N and 60°N. The equidistant conic projection with Tissot's indicatrix of deformation. Standard parallels of 15°N and 45°N.
|
|
"I was unable to locate large-scale reproductions, drawings, or computations," he wrote, "so I set about drawing my own Cahill from scratch". "On November 4th, 1975, after 40-days and nights," notes an article in Wired Magazine on Keyes' forty year quest, "he emerged with a six-and-a-half square foot, hand-drawn, featureless graticule". A graticule is a network of lines or a grid (latitudes and longitudes) on which a map can be projected. He sketched in North America and eventually the whole world.
|
|
Strebe 1995 projection. 15° graticule, 11°E central meridian. Imagery is a derivative of NASA’s Blue Marble summer month composite with oceans lightened to enhance legibility and contrast. Image created with the Geocart map projection software.
|
|
These permit internal circuits to make more refined measurements. Both calibrated vertical sensitivity and calibrated horizontal time are set in steps. This leads, however, to some awkward interpretations of minor divisions. Digital oscilloscopes generate the graticule digitally.
|
|
Gall isographic projection. 15° graticule. Gall isographic projection is a specific instance of equirectangular projection such that its standard parallels are north and south 45°. The projection is named after James Gall, who presented it in 1855.
|
|
A graticule is another term for reticle, frequently encountered in British and British military technical manuals, and came into common use during World War One.Glazebrook, Sir Richard, A Dictionary of Applied Physics, Macmillan and Co., London, 1923.
|
|
Raisz armadillo projection of the world. Tissot indicatrix on Raisz armadillo projection, 15° graticule. Color shows angular deformation and areal inflation/deflation in a bivariate scheme: The lighter the color, the less distortion. The redder, the more angular distortion.
|
|
Sculptor Matthew Sanderson modelled the Chronophage. The graticule, or measuring dish, for the Corpus Clock was designed and created by Alan Meeks of Visitech Design. It was machined in aluminium and silver before being plated with gold and rhodium.
|
|
Ortelius oval projection of the world. Tissot indicatrix on Ortelius oval projection, 15° graticule. Color shows angular deformation and areal inflation/deflation in a bivariate scheme: The lighter the color, the less distortion. The redder, the more angular distortion.
|
|
A video vectorscope displaying color bars. The diagonal direction of the color burst vector is indicative of a PAL signal. The graticule of an NTSC vectorscope. A vectorscope is a special type of oscilloscope used in both audio and video applications.
|
|
A vectorscope uses an overlaid circular reference display, or graticule, for visualizing chrominance signals, which is the best method of referring to the QAM scheme used to encode color into a video signal. The actual visual pattern that the incoming chrominance signal draws on the vectorscope is called the trace. Chrominance is measured using two methods—color saturation, encoded as the amplitude, or gain, of the subcarrier signal, and hue, encoded as the subcarrier's phase. The vectorscope's graticule roughly represents saturation as distance from the center of the circle, and hue as the angle, in standard position, around it.
|
|
Goode homolosine projection of the world. Tissot indicatrix on Goode homolosine projection, 15° graticule. The Goode homolosine projection (or interrupted Goode homolosine projection) is a pseudocylindrical, equal-area, composite map projection used for world maps. Normally it is presented with multiple interruptions.
|
|
It was revised in 1980, under the direction of Jorge Alarcão and supervised by Drs. Monteiro and Quinteira, from the Faculty of Letters at the University of Coimbra. This intervention used a stratigraphic method of excavation, utilizing a graticule plan of the site.
|
|
Quartic authalic projection of the world. 15° graticule. In cartography, the quartic authalic projection is an equal-area projection developed by Karl Siemon in 1937 and independently by O.S. Adams in 1944. The meridians in this projection are fourth-order polynomial curves.
|
|
Boggs eumorphic projection of the world. Tissot indicatrix on Boggs eumorphic projection, 15° graticule, gradations every 10° of angular deformation. The Boggs eumorphic projection is a pseudocylindrical, equal-area map projection used for world maps. Normally it is presented with multiple interruptions.
|
|
Hemispheres on the Nicolosi globular projection. 15° graticule, 115°W and 65°E central meridians. Imagery is a derivative of NASA’s Blue Marble summer month composite with oceans lightened to enhance legibility and contrast. Image created with the Geocart map projection software.
|
|
Stereographic projection of the world north of 30°S. 15° graticule. The stereographic projection with Tissot's indicatrix of deformation. The stereographic projection, also known as the planisphere projection or the azimuthal conformal projection, is a conformal map projection whose use dates back to antiquity.
|
|
Vertical perspective from an altitude of 35,786 km over (0°, 90°W), corresponding to a view from geostationary orbit. 10° graticule. The vertical perspective projection showing exactly one third of the Earth's surface, with Tissot's indicatrix of deformation. The General Perspective projection is a map projection.
|
|
The total length of each side is 10,043 km. The inner meridians converge towards the pole. Each 1° and 5° "tile" are proportional to each other. The specific process for constructing the graticule divides each half-octant into twelve zones, each of which has different formulae for coordinate calculations.
|
|
A third model is the geoid, a more complex and accurate representation of Earth's shape coincident with what mean sea level would be if there were no winds, tides, or land. Compared to the best fitting ellipsoid, a geoidal model would change the characterization of important properties such as distance, conformality and equivalence. Therefore, in geoidal projections that preserve such properties, the mapped graticule would deviate from a mapped ellipsoid's graticule. Normally the geoid is not used as an Earth model for projections, however, because Earth's shape is very regular, with the undulation of the geoid amounting to less than 100 m from the ellipsoidal model out of the 6.3 million m Earth radius.
|
|
There is also a last round indicator. The day sight has a wide field of view (22°) with 1x magnification and a collimated aiming circle, and a narrow field of view (8°) with 8x magnification and a ballistic graticule. The night sight has a wide field of view (22°) with 1x magnification and collimated aiming circle, and a narrow field of view (7°) with 7x magnification, a 25 mm image intensifier tube, and a ballistic graticule. Standard equipment includes an air conditioning system, a heater and defogger, an infrared driving headlamp, a blackout lighting system, a smoke extraction fan mounted on the roof, thick polyurethane roof and body interior lining for thermal and noise insulation, an explosion-suppressed fuel tank, and Hutchinson run-flat tires.
|
|
The central cylindrical projection with a 15° graticule, approximately to latitude ±72°. Distortion is noticeably worse than that of the Mercator projection. The central cylindrical projection is a perspective cylindrical map projection. It corresponds to projecting the Earth's surface onto a cylinder tangent to the equator as if from a light source at Earth's center.
|
|
An analog oscilloscope, as shown in the illustration, is typically divided into four sections: the display, vertical controls, horizontal controls and trigger controls. The display is usually a CRT with horizontal and vertical reference lines called the graticule. CRT displays also have controls for focus, intensity, and beam finder. The vertical section controls the amplitude of the displayed signal.
|
|
A computer model of the sweep of the oscilloscopeSome oscilloscopes have cursors. These are lines that can be moved about the screen to measure the time interval between two points, or the difference between two voltages. A few older oscilloscopes simply brightened the trace at movable locations. These cursors are more accurate than visual estimates referring to graticule lines.
|
|
Cahill butterfly, conformal version of the projection. 15° graticule, 157°30′E central meridian. From cover of 1919 pamphlet by Cahill, "The Butterfly Map", 8 p. Bernard Joseph Stanislaus Cahill (London, January 30, 1866 - Alameda County, October 4, 1944), American cartographer and architect, was the inventor of the octahedral "Butterfly Map" (published in 1909 and patented in 1913).
|
|
The combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a "graticule". The origin/zero point of this system is located in the Gulf of Guinea about south of Tema, Ghana.
|
|
Hahn, p. 148. The EZ 42 was compared with the Allied G.G.S. captured from in a P-47 Thunderbolt in September 1944 in Germany. Both sights were tested in the same Fw 190, and by the same pilot. The conclusion was critical of the moving graticule of the G.G.S., which could be obscured by the target.
|
|
The gunner has a Barr & Stroud TLS (Tank Laser Sight) with a magnification of ×1 and ×10, which is also provided with a ballistic graticule. Mk. 3s for the Nigerian Army, for which production began in 1981, are also fitted with a Vickers Instruments L23Jane's Armour and Artillery 2003–2004 gunner's laser rangefinder incorporating a Simrad LV352 laser.
|
|
PSDs can be measured microscopically by sizing against a graticule and counting, but for a statistically valid analysis, millions of particles must be measured. This is impossibly arduous when done manually, but automated analysis of electron micrographs is now commercially available. It is used to determine the particle size within the range of 0.2 to 100 micrometers.
|
|
The flag is set against a royal blue field. It features a royal blue Wright Flyer superimposed on a gray globe with white graticule lines, representing the aviation industry's global reach. The globe is surrounded by a white cogwheel, representing Dayton as a manufacturing hub. The name "DAYTON" is inscribed along the mast in white, slab serif lettering.
|
|
However, in publications, the projection often develops a "pigtail" which shows the rest of Australia as well as New Zealand. Raisz coined the term orthoapsidal as a combination of orthographic and apsidal. He used it to mean drawing a parallel-meridian network, or graticule, on any suitable solid other than a sphere, and then making an orthographic projection of that.
|
|
The graticule is also embellished with several elements corresponding to the various components of the standard color bars video test signal, including boxes around the circles for the colors in the main bars, and perpendicular lines corresponding to the U and V components of the chrominance signal (and additionally on an NTSC vectorscope, the I and Q components). NTSC vectorscopes have one set of boxes for the color bars, while their PAL counterparts have two sets of boxes, because the R-Y chrominance component in PAL reverses in phase on alternating lines. Another element in the graticule is a fine grid at the nine-o'clock, or -U position, used for measuring differential gain and phase. Often two sets of bar targets are provided: one for color bars at 75% amplitude and one for color bars at 100% amplitude.
|
|
Computer model of vertical position y offset varying in a sine way The vertical position control moves the whole displayed trace up and down. It is used to set the no-input trace exactly on the center line of the graticule, but also permits offsetting vertically by a limited amount. With direct coupling, adjustment of this control can compensate for a limited DC component of an input.
|
|
Author and publisher of Free City of Kraków maps from 1833, city map of Kraków from 1834 and health resorts map of Galicia and Bukowina. Żebrawski derived the chain curve formula and applied it to the bridge arc calculations. He published a paper on the main causes of train derailment and its present methods. He introduced his own method of maps and map graticule classification.
|
|
The ruler the simplest kind of length measurement tool: lengths are defined by printed marks or engravings on a stick. The meter was initially defined using a ruler before more accurate methods became available. Gauge blocks are a common method for precise measurement or calibration of measurement tools. For small or microscopic objects, microphotography where the length is calibrated using a graticule can be used.
|
|
The medal is 1 3/8 inches in diameter, made of gold plated red brass. The obverse depicts a triskelion superimposed over a graticule surrounded by a laurel wreath. The reverse bears the words, in relief, DEPARTMENT OF TRANSPORTATION arched above with the incuse inscription OUTSTANDING ACHIEVEMENT on a scroll below. In the middle are the words AWARDED TO with a space to engrave the recipient's name.
|
|
Computer model of horizontal position control from x offset increasing The horizontal position control moves the display sidewise. It usually sets the left end of the trace at the left edge of the graticule, but it can displace the whole trace when desired. This control also moves the X-Y mode traces sidewise in some instruments, and can compensate for a limited DC component as for vertical position.
|
|
This series is used to define the scales for graphs and for instruments that display in a two-dimensional form with a graticule, such as oscilloscopes. The denominations of most modern currencies, notably the euro and British pound, follow a 1–2–5 series. The United States and Canada follow the approximate 1–2–5 series 1, 5, 10, 25, 50, 100 (cents), $1, $2, $5, $10, $20, $50, $100.
|
|
Valcamonica rock art (I), Paspardo r. 29, topographic composition, 4th millennium BCE The Bedolina Map and its tracing, 6th–4th century BCE A 14th- century Byzantine map of the British Isles from a manuscript of Ptolemy's Geography, using Greek numerals for its graticule: 52–63°N of the equator and 6–33°E from Ptolemy's Prime Meridian at the Fortunate Isles. St. Isidore's TO map of the world.
|
|
In some eyepiece types, such as Ramsden eyepieces (described in more detail below), the eyepiece behaves as a magnifier, and its focal plane is located outside of the eyepiece in front of the field lens. This plane is therefore accessible as a location for a graticule or micrometer crosswires. In the Huygenian eyepiece, the focal plane is located between the eye and field lenses, inside the eyepiece, and is hence not accessible.
|
|
The exposed papers were returned underground for assessment. The pre-exposed papers had a graticule grid exposed on the papers that showed degrees of bearing. The fireball from any nuclear burst within range would have burned a mark on the paper. The spot size and bearing would be reported to the group control together with an indication that the spot is touching or clear of the horizon, essential for indicating an air or ground burst.
|
|
In an analog oscilloscope, the vertical amplifier acquires the signal[s] to be displayed and provides a signal large enough to deflect the CRT's beam. In better oscilloscopes, it delays the signal by a fraction of a microsecond. The maximum deflection is at least somewhat beyond the edges of the graticule, and more typically some distance off-screen. The amplifier has to have low distortion to display its input accurately (it must be linear), and it has to recover quickly from overloads.
|
|
GS50 projection with 15° graticule GS50 projection, with lines of constant scale factor superimposed. All 50 states, including islands and passages between Alaska, Hawaii, and the conterminous 48 states are shown with scale factors ranging only from 1.02 to 0.98 GS50 is a map projection that was developed by John Parr Snyder of the USGS in 1982. The GS50 projection provides a conformal projection suitable only for maps of the 50 United States. Scale varies less than 2% throughout the area covered.
|
|
Winkel tripel projection of the world, 15° graticule The Winkel tripel projection with Tissot's indicatrix of deformation The Winkel tripel projection (Winkel III), a modified azimuthal map projection of the world, is one of three projections proposed by German cartographer Oswald Winkel (7 January 1874 – 18 July 1953) in 1921. The projection is the arithmetic mean of the equirectangular projection and the Aitoff projection: The name tripel (German for "triple") refers to Winkel's goal of minimizing three kinds of distortion: area, direction, and distance.
|
|
The focal plane is thus located outside of the eyepiece and is hence accessible as a location where a graticule, or micrometer crosshairs may be placed. Because a separation of exactly one focal length would be required to correct transverse chromatic aberration, it is not possible to correct the Ramsden design completely for transverse chromatic aberration. The design is slightly better than Huygens but still not up to today’s standards. It remains highly suitable for use with instruments operating using near-monochromatic light sources e.g. polarimeters.
|
|
Peak-to-peak amplitude (abbreviated p–p) is the change between peak (highest amplitude value) and trough (lowest amplitude value, which can be negative). With appropriate circuitry, peak-to-peak amplitudes of electric oscillations can be measured by meters or by viewing the waveform on an oscilloscope. Peak-to-peak is a straightforward measurement on an oscilloscope, the peaks of the waveform being easily identified and measured against the graticule. This remains a common way of specifying amplitude, but sometimes other measures of amplitude are more appropriate.
|
|
The graticule is a grid of lines that serve as reference marks for measuring the displayed trace. These markings, whether located directly on the screen or on a removable plastic filter, usually consist of a 1 cm grid with closer tick marks (often at 2 mm) on the centre vertical and horizontal axis. One expects to see ten major divisions across the screen; the number of vertical major divisions varies. Comparing the grid markings with the waveform permits one to measure both voltage (vertical axis) and time (horizontal axis).
|
|
The Atlas Coeli covers both hemispheres with 16 charts. The coordinate system is referred to equinox 1950.0 and the scale is 1° = 0.75 cm. There are six charts of the equatorial regions on a rectangular graticule, covering declinations from +25° to -25°; four charts for each hemisphere with straight, converging hour circles and concentric, equally-spaced declination circles covering declinations 20° - 65°; and, for each hemisphere, a circumpolar chart covering declination 65° to the pole. All stars brighter than 7.75 magnitude are included, for a total of 32,571.
|
|
The definitions of latitude and longitude on such reference surfaces are detailed in the following sections. Lines of constant latitude and longitude together constitute a graticule on the reference surface. The latitude of a point on the actual surface is that of the corresponding point on the reference surface, the correspondence being along the normal to the reference surface which passes through the point on the physical surface. Latitude and longitude together with some specification of height constitute a geographic coordinate system as defined in the specification of the ISO 19111 standard.
|
|
A focus finder is a simple optical tool used to examine a virtual image in an optical device to achieve a precise point of focus. They are most commonly used in photographic enlarging to ensure that the negative image is accurately focussed on the easel. Focus finders are designed so that their optical path is exactly equal to the optical path of the uninterrupted light. In enlarging, this is achieved by mounting an angled front-silvered mirror on a small plinth and using a strong magnifying eyepiece and graticule to examine the reflected virtual image.
|
|
Loximuthal projection of the world, central point = 0°E, 30°N. 15° graticule. In cartography, the loximuthal projection is a map projection introduced by Karl Siemon in 1935, and independently in 1966 by Waldo R. Tobler, who named it. It is characterized by the fact that loxodromes (rhumb lines) from one chosen central point (the intersection of the central meridian and central latitude) are shown straight lines, correct in azimuth from the center, and are "true to scale" in the sense that distances measured along such lines are proportional to lengths of the corresponding rhumb lines on the surface of the earth.
|
|
Computer model of the impact of increasing the timebase time/division These select the horizontal speed of the CRT's spot as it creates the trace; this process is commonly referred to as the sweep. In all but the least-costly modern oscilloscopes, the sweep speed is selectable and calibrated in units of time per major graticule division. Quite a wide range of sweep speeds is generally provided, from seconds to as fast as picoseconds (in the fastest) per division. Usually, a continuously-variable control (often a knob in front of the calibrated selector knob) offers uncalibrated speeds, typically slower than calibrated.
|
|
The isometric latitude, , is used in the development of the ellipsoidal versions of the normal Mercator projection and the Transverse Mercator projection. The name "isometric" arises from the fact that at any point on the ellipsoid equal increments of and longitude give rise to equal distance displacements along the meridians and parallels respectively. The graticule defined by the lines of constant and constant , divides the surface of the ellipsoid into a mesh of squares (of varying size). The isometric latitude is zero at the equator but rapidly diverges from the geodetic latitude, tending to infinity at the poles.
|
|
The safety catch is in front of the trigger guard and when activated physically blocks insertion of a finger into the trigger-guard. The rifle features a quick change lever for swapping optics, and was provided with a recommended 4x optical sight with a tritium powered graticule. Iron sights were also available and the mounting did accept other optics. As with the Steyr ACR, the sabots left the barrel at high speed, this was noted as presenting a potential danger to other soldiers, as well as to the shooter if they bounced off the ground when firing prone.
|
|
A comparison of different reticles used in telescopic sights. The lower right represents a reticle found in the PSO-1 scope of a Russian SVD designated marksman rifle. Reticle of Bell & Howell Pocket Comparator A reticle, or reticuleA Christopher Gorse, David Johnston, Martin Pritchard, Dictionary of Construction, Surveying and Civil Engineering (2 ed.), Oxford University Press, 2020 - reticuledictionary.com - reticule (), also known as a graticule (), is a pattern of fine lines or markings built into the eyepiece of a sighting device, such as a telescopic sight in a telescope, a microscope, or the screen of an oscilloscope, to provide measurement references during visual examination.
|
|
The graticule is formed by the lines of constant latitude and constant longitude, which are constructed with reference to the rotation axis of the Earth. The primary reference points are the poles where the axis of rotation of the Earth intersects the reference surface. Planes which contain the rotation axis intersect the surface at the meridians; and the angle between any one meridian plane and that through Greenwich (the Prime Meridian) defines the longitude: meridians are lines of constant longitude. The plane through the centre of the Earth and perpendicular to the rotation axis intersects the surface at a great circle called the Equator.
|
|
If the collimated beam falls perpendicularly onto a plane reflecting surface, the light is reflected back along its original path and is brought to a focus at a point coincident with the origin point. If the reflector is tilted through an angle θ, the reflected beam is deflected through an angle 2θ, and the image I is displaced laterally from the origin 0.The amount of displacement is given by d=2θf where f is the focal length of the lens, and θ is in radians. Light from an illuminated target graticule at the focus of an objective lens is directed towards the lens by a beam splitter.
|
|
In digital (and component analog) vectorscopes, colorburst doesn't exist; hence the phase relationship between the colorburst signal and the chroma subcarrier is simply not an issue. A vectorscope for SECAM uses a demodulator similar to the one found in a SECAM receiver to retrieve the U and V colour signals since they are transmitted one at a time (Thomson 8300 Vecamscope). On older vectorscopes that use cathode ray tubes (CRTs), the graticule was often a silk-screened overlay superimposed over the front surface of the screen. One notable exception was the Tektronix WFM601 series of instruments, which are combined waveform monitors and vectorscopes used to measure CCIR 601 television signals.
|
|
Hawaii is mapped at this scale in quadrangles measuring 1° by 1°. USGS topographic quadrangle maps are marked with grid lines and tics around the map collar which make it possible to identify locations on the map by several methods, including the graticule measurements of longitude and latitude, the township and section method within the Public Land Survey System, and cartesian coordinates in both the State Plane Coordinate System and the Universal Transverse Mercator coordinate system. Other specialty maps have been produced by the USGS at a variety of scales. These include county maps, maps of special interest areas, such as the national parks, and areas of scientific interest.
|
|
The World Geodetic System WGS84 ellipsoid is now generally used to model the Earth in the UTM coordinate system, which means current UTM northing at a given point can differ up to 200 meters from the old. For different geographic regions, other datum systems can be used. Prior to the development of the Universal Transverse Mercator coordinate system, several European nations demonstrated the utility of grid-based conformal maps by mapping their territory during the interwar period. Calculating the distance between two points on these maps could be performed more easily in the field (using the Pythagorean theorem) than was possible using the trigonometric formulas required under the graticule-based system of latitude and longitude.
|
|
A similar error occurs when reading the position of a pointer against a scale in an instrument such as an analog multimeter. To help the user avoid this problem, the scale is sometimes printed above a narrow strip of mirror, and the user's eye is positioned so that the pointer obscures its own reflection, guaranteeing that the user's line of sight is perpendicular to the mirror and therefore to the scale. The same effect alters the speed read on a car's speedometer by a driver in front of it and a passenger off to the side, values read from a graticule not in actual contact with the display on an oscilloscope, etc.
|
|
Today, engraved lines or embedded fibers may be replaced by a computer-generated image superimposed on a screen or eyepiece. Both terms may be used to describe any set of lines used for optical measurement, but in modern use reticle is most commonly used for gunsights and such, while graticule is more widely used for the oscilloscope display, microscope slides, and similar roles. Reticle accessory (PD-8) used in sniper rifles There are many variations of reticles; this article concerns itself mainly with a simple reticle: crosshairs. Crosshairs are most commonly represented as intersecting lines in the shape of a cross, "+", though many variations exist, including dots, posts, circles, scales, chevrons, or a combination of these.
|
|
Byzantine manuscript of Hero of Alexandria's Metrika. The first line contains the number "", i.e. "". It features each of the special numeral symbols sampi (ϡ), koppa (ϟ), and stigma (ϛ) in their minuscule forms. Ptolemy's Geography, using Greek numerals for its graticule: 52–63°N of the equator and 6–33°E from Ptolemy's Prime Meridian at the Fortunate Isles. Greek numerals are decimal, based on powers of 10. The units from 1 to 9 are assigned to the first nine letters of the old Ionic alphabet from alpha to theta. Instead of reusing these numbers to form multiples of the higher powers of ten, however, each multiple of ten from 10 to 90 was assigned its own separate letter from the next nine letters of the Ionic alphabet from iota to koppa. Each multiple of one hundred from 100 to 900 was then assigned its own separate letter as well, from rho to sampi.
|
|
Weapon Control in the Royal Navy 1935-45, PoutBritish Mechanical Gunnery Computers of World War II, Bromley, p22 The HACS also displayed the predicted bearing and elevation of the target on indicators in the Director tower, or on later variants,Naval Weapons of World War Two, Campbell, P.30 the HACS could move the entire Director through Remote Power Control so that it could continue to track the target if the target became obscured.HACS III Operating Manual Part 2, paragraph 174 (a) The angle measured by the graticule also caused a metal wire to rotate around the face of a large circular display on one side of the HACS, known as the Deflection Display. The measured value of altitude and range, and estimated value of target speed, caused optics to focus a lamp onto a ground glass screen behind the wire, displaying an ellipse who's shape changed based on these measures. The deflection operator used two controls to move additional wire indicators so they lay on top of the intersection of the outer edge of the ellipse where it was crossed by the rotating metal wire.
|
|