"per day is observed and recorded on a rating certificate which accompanies the instrument. This daily rate is used in the field to correct the time indicated by the instrument to get an accurate time reading. Even the best-made chronometer with the finest temperature compensation etc. exhibits two types of error, (1) random and (2) consistent. The quality of design and manufacture of the instrument keeps the random errors small. In principle, the consistent errors should be amenable to elimination by adjustment, but in practice it is not possible to make the adjustment so precisely that this error is completely"
"often confused with the term chronometer. Where ""Chronograph"" refers to the function of a watch, chronometer is a measure of how well a given mechanical timepiece performs: in order to be labeled a chronometer the timepiece must be certified by the COSC, the official Swiss Chronometer testing institute, after undergoing a series of rigorous tests for robustness, accuracy and precision under adverse conditions (though these requirements fall far short of the accuracy achieved by even the cheapest modern quartz watch). A simple mechanical watch, without the stopwatch functionality, can be certified a chronometer, as can a clock, for example a"
"Chronometer watch A chronometer () is a specific type of mechanical timepiece tested and certified to meet certain precision standards. In Switzerland, only timepieces certified by the Contrôle Officiel Suisse des Chronomètres (COSC) may use the word ""chronometer"" on them. Outside Switzerland, equivalent bodies (such as the Japan Chronometer Inspection Institute) have in the past certified timepieces to the same internationally recognised standards, although use of the term has not always been strictly controlled. The term ""chronometer"" was coined by Jeremy Thacker of Beverley, England in 1714, referring to his invention of a clock ensconced in a vacuum chamber. The"
"a chronometer watch is a timepiece that has met an industry standard test for performance under pre-defined conditions: a chronometer is a high quality mechanical or a thermo-compensated movement that has been tested and certified to operate within a certain standard of accuracy by the COSC (Contrôle Officiel Suisse des Chronomètres). The concepts are different but not mutually exclusive; so a watch can be a chronograph, a chronometer, both, or neither. Many computerized wristwatches have been developed, but none have had long-term sales success, because they have awkward user interfaces due to the tiny screens and buttons, and a short"
"precision watch capable of displaying the seconds and housing a movement that has been tested over several days, in different positions, and at different temperatures, by an official, neutral body (COSC). Each movement is individually tested for several consecutive days, in five positions and at three temperatures. Each movement is individually measured. Any watch with the denomination ""chronometer"" contains a certified movement and matches the criteria in ISO 3159. Chronometer watch A chronometer () is a specific type of mechanical timepiece tested and certified to meet certain precision standards. In Switzerland, only timepieces certified by the Contrôle Officiel Suisse des"
"contain a maintaining power which keeps the chronometer going while it is being wound, and a power reserve to indicate how long the chronometer will continue to run without being wound. Marine chronometers are the most accurate portable mechanical clocks ever made, achieving a precision of around a 0.1 second per day or less than one minute per year. This is accurate enough to locate a ship's position within 1–2 miles (2–3 km) after a month's sea voyage. In strictly horological terms, ""rating"" a chronometer means that prior to the instrument entering service, the average rate of gaining or losing"
"personal value, due to an awareness of the limited time in each day and in human life spans. Generally speaking, methods of temporal measurement, or chronometry, take two distinct forms: the calendar, a mathematical tool for organising intervals of time, and the clock, a physical mechanism that counts the passage of time. In day-to-day life, the clock is consulted for periods less than a day whereas the calendar is consulted for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of"
"Chronograph A chronograph is a specific type of watch that is used as a stopwatch combined with a display watch. A basic chronograph has an independent sweep second hand; it can be started, stopped, and returned to zero by successive pressure on the stem. More complex chronographs use additional complications and can have multiple independent hands to measure seconds, minutes, hours and even tenths of a second. In addition, many modern chronographs use moveable bezels as tachymeters for rapid calculations of speed or distance. Louis Moinet invented the chronograph in 1816 for use in tracking astronomical objects. Chronographs were also"
"measure an industrial production process in units per hour. A tachymeter is simply a means of converting ""elapsed time"" (in seconds per unit) to ""speed"" (in units per hour). To use a tachymeter-equipped watch for measuring speed, start the chronograph at a starting marker of a known distance. At the next marker, the point on the scale adjacent to the second hand indicates the speed (in distance between markers per hour) of travel between the two. The typical tachymeter scale on a watch converts between the number of seconds it takes for an event to happen and the number of"
"calculations of distance traveled over time. Metered bezels: Many chronographs have a bezel, that is either fixed or can rotate, around the outside of the dial that is marked to specific scales to allow rapid calculations. While any wristwatch can have a bezel, the chronograph stop start feature, as well as the rotation of the bezel, allows more complex calculations or repeated measurements for a series of calculations. The most popular meter is for Tachymeter readings: a simple scale that allows rapid calculations of speed. Other bezels feature Telemeter scale, for distance. The watchmaking company Breitling offers a model with"
"Tachymeter (watch) A tachymeter (pronounced ) scale is a scale sometimes inscribed around the rim of an analog watch with a chronograph. It can be used to compute a speed based on travel time or measure distance based on speed. The spacings between the marks on the tachymeter dial are therefore proportional to , where ""t"" is the elapsed time. The function performed by a tachymeter is independent of the unit of distance (e.g. statute miles, nautical miles, kilometres, metres etc.) as long as the same unit of length is used for all calculations. It can also be used to"
"the Langley Chronograph, which is used by the US Navy to record, calculate, and analyse data given off by aeroplane launching catapults. Another famous usage of the chronograph was during all of NASA's Apollo missions to the moon, each astronaut was equipped with a fully functioning chronograph, the Omega Speedmaster. You can now find chronographs that are used to record heart beats within hospitals, calculate speed and/or distance on an athletic field, or even as simple as a cooking tool for the kitchen. Chronographs can be extremely complicated devices, but they all have the basic function of telling time, as"
"using minute hand, align index bezel to the second hand and observe passing one unit of distance when position of the second hand will then indicate average speed. Tachymeter (watch) A tachymeter (pronounced ) scale is a scale sometimes inscribed around the rim of an analog watch with a chronograph. It can be used to compute a speed based on travel time or measure distance based on speed. The spacings between the marks on the tachymeter dial are therefore proportional to , where ""t"" is the elapsed time. The function performed by a tachymeter is independent of the unit of"
"Mental chronometry Mental chronometry is the use of response time in perceptual-motor tasks to infer the content, duration, and temporal sequencing of cognitive operations. Mental chronometry is one of the core paradigms of experimental and cognitive psychology, and has found application in various disciplines including cognitive psychophysiology, cognitive neuroscience, and behavioral neuroscience to elucidate mechanisms underlying cognitive processing. Mental chronometry is studied using measurements of reaction time (RT), which is the elapsed time between the presentation of a sensory stimulus and the subsequent behavioral response. In psychometric psychology it is considered to be an index of processing speed. That is,"
"Chronocinematograph Chronocinematograph is an astronomical instrument consisting of a film camera, chronometer and chronograph. The device records images using a more precise timetable for observing an eclipse. It was invented in 1927 by a Polish astronomer, mathematician and geodesist Tadeusz Banachiewicz for observing total solar eclipses. During the same year, Banachiewcz used his device for solar observations in Lapland (Sweden), then in USA (1932) and Greece, Japan and Siberia (1936). The invention enhanced the precision for determining the time of an eclipse, due to more precisely timed photos of Baily's beads, and quantifying the duration of totality. This could not"
"Gun chronograph A gun chronograph or shooting chronograph is an instrument used to measure the velocity of a projectile fired by a gun. Benjamin Robins (1707-1751) invented the ballistic pendulum that measures the momentum of the projectile fired by a gun. Dividing the momentum by the projectile mass gives the velocity. Robbins published his results as ""New Principles of Gunnery"" in 1742. The ballistic pendulum could make only one measurement per firing because the device catches the projectile. The gun's accuracy also limited how far down range a measurement could be made. An early chronograph that measures velocity directly was"
"Horology Horology (""the study of time"", related to Latin ""horologium"" from Greek , ""instrument for telling the hour"", from ""hṓra"" ""hour; time"" and -o- interfix and suffix ""-logy"") is the study of the measurement of time. Clocks, watches, clockwork, sundials, hourglasses, clepsydras, timers, time recorders, marine chronometers and atomic clocks are all examples of instruments used to measure time. In current usage, horology refers mainly to the study of mechanical time-keeping devices, while chronometry more broadly includes electronic devices that have largely supplanted mechanical clocks for the best accuracy and precision in time-keeping. People interested in horology are called ""horologists""."
"are based on ISO 3159 which defines a wrist chronometer with spring-balance oscillator. Only movements which meet the precision criteria established under ISO 3159 are granted an official chronometer certificate. (Compare ISO 3158.) Each uncased movement is individually tested for fifteen days, in five positions, at three different temperatures. The movements are fitted with a seconds hand and the automatic winding mechanisms are disengaged for the tests. Measurements are made daily with the aid of cameras. Based on these measurements, seven eliminatory criteria are calculated, each of which must be met (e.g., for movements of a diameter over 20 mm,"
"from a spring-driven watch principally in that it contains a variable lever device to maintain even pressure on the mainspring, and a special balance designed to compensate for temperature variations. A spring-driven chronometer is set approximately to Greenwich mean time (GMT) and is not reset until the instrument is overhauled and cleaned, usually at three-year intervals. The difference between GMT and chronometer time is carefully determined and applied as a correction to all chronometer readings. Spring-driven chronometers must be wound at about the same time each day. Quartz crystal marine chronometers have replaced spring-driven chronometers aboard many ships because of"
"due to a successful participation in the competition which resulted in the issuance of a ""Bulletin de Marche"". All database entries are submissions to the wristwatch category (""chronometres-bracelet"") at the observatory competition. The term ""chronometer"" is often wrongly applied to timekeeping instruments fitted with an additional mechanism that may be set in motion by pushbuttons to enable measurement of the duration of an event. Such an instrument is in fact a chronograph or chronoscope. It may of course be chronometer-certified, provided it meets the criteria set for the standard. A mechanical chronometer is a spring-driven escapement timekeeper, like a watch,"
"how long it has been since the start button has been activated. Tachymeter bezels are a complication that allows rapid calculations of speed or distance. Rotating bezels allow for more complex calculations or repeated calculations without requiring a reset of the timer. The original chronographs that Rieussec invented were called tape chronographs. They consisted of a tape that was constantly being dragged along at a controlled speed. When activated, a pen would be pushed onto the tape and begin recording until deactivated. Specialized chronographs are used by deep sea and scuba divers. While basic functionality is the same as other"
"can also be used by itself to shoot a succession of lines of position (best done around local noon) to determine a position. In order to accurately measure longitude, the precise time of a sextant sighting (down to the second, if possible) must be recorded. Each second of error is equivalent to 15 seconds of longitude error, which at the equator is a position error of .25 of a nautical mile, about the accuracy limit of manual celestial navigation. The spring-driven marine chronometer is a precision timepiece used aboard ship to provide accurate time for celestial observations. A chronometer differs"
"have been observed as closely as before due to the brightness of the sun. Chronocinematograph Chronocinematograph is an astronomical instrument consisting of a film camera, chronometer and chronograph. The device records images using a more precise timetable for observing an eclipse. It was invented in 1927 by a Polish astronomer, mathematician and geodesist Tadeusz Banachiewicz for observing total solar eclipses. During the same year, Banachiewcz used his device for solar observations in Lapland (Sweden), then in USA (1932) and Greece, Japan and Siberia (1936). The invention enhanced the precision for determining the time of an eclipse, due to more precisely"
"chronograph"" and the ""digital chronograph"". The automatic chronograph depends solely on kinetic energy as its power source, while the digital chronograph is much like the common stopwatch and uses a battery to gain power, as well as quartz for timing. Other, more specific, types of chronographs include split second chronographs, tide chronographs, and asthometer chronographs. Each of these chronographs has an added feature that sets them apart. Chronograph A chronograph is a specific type of watch that is used as a stopwatch combined with a display watch. A basic chronograph has an independent sweep second hand; it can be started,"
"accurately measure the velocity of various projectiles fired at hyper-velocities into a variety of engineered materials in anticipation of manned space flight. His first design was an open rectangular frame of square aluminum tubing with a screen of fine copper wire at both ends. Breaking the first wire started charging a capacitor, breaking the second wire stopped it. Measuring the accumulated voltage and knowing the rate of charge the elapsed time could be accurately calculated. Gun chronograph A gun chronograph or shooting chronograph is an instrument used to measure the velocity of a projectile fired by a gun. Benjamin Robins"
"the Clock of the Long Now. They can be driven by a variety of means, including gravity, springs, and various forms of electrical power, and regulated by a variety of means such as a pendulum. Alarm clocks first appeared in ancient Greece around 250 BC with a water clock that would set off a whistle. This idea was later mechanized by Levi Hutchins and Seth E. Thomas. A chronometer is a portable timekeeper that meets certain precision standards. Initially, the term was used to refer to the marine chronometer, a timepiece used to determine longitude by means of celestial navigation,"
"altitude sight, the navigator can work out his longitude. The considerably more popular method was (and still is) to use an accurate timepiece to directly measure the time of a sextant sight. The need for accurate navigation led to the development of progressively more accurate chronometers in the 18th century (see John Harrison). Today, time is measured with a chronometer, a quartz watch, a shortwave radio time signal broadcast from an atomic clock, or the time displayed on a GPS. A quartz wristwatch normally keeps time within a half-second per day. If it is worn constantly, keeping it near body"
"differences in accuracy garnered by the successive grades, consider the following specifications: The Chronometer grade must meet strict standards prescribed by the COSC. Chronometer grade movements are serial numbered, as that is a requirement of the certification authority. Moreover, it should be noted that the degree of decoration on the movement's parts, generally only an aesthetic improvement, increases as well with the grade. The ETA 2892.A2 is a newer design dating to the 1970s and fitted with top quality components. An automatic winding, twenty-one (21) jewel movement, the 2892 is available in three executions or grades: ""Elaborated"", ""Top"" and ""Chronometer""."
"counter information is supplemented with two time interpolators: one interpolator measures the (short) interval between the start event and a following clock event, and the second interpolator measure the interval between the stop event and a following clock event. The basic idea has some complications: the start and stop events are asynchronous, and one or both might happen close to a clock pulse. The counter and interpolators must agree on matching the start and end clock events. To accomplish that goal, synchronizers are used. The common hybrid approach is the Nutt method. In this example the fine measurement circuit measures"
"Chronomètre of Loulié The chronomètre is a precursor of the metronome. It was invented circa 1694 by Étienne Loulié to record the preferred tempo of pieces of music. Circa 1694 Étienne Loulié, a musician who had recently collaborated with mathematician Joseph Sauveur on the education of Philippe, Duke of Chartres, was asked by Chartres to work with Sauveur on a scientific study of acoustics sponsored by the Royal Academy of Science. To measure scientifically the number of beats per second caused by different dissonances, they used the ""seconds pendulum"" invented by Galileo earlier in the century. It doubtlessly was these"
"manuscript and print. Loulié's own description of the invention follows, translated from pp. 83–86 of his ""Éléments"": Chronomètre of Loulié The chronomètre is a precursor of the metronome. It was invented circa 1694 by Étienne Loulié to record the preferred tempo of pieces of music. Circa 1694 Étienne Loulié, a musician who had recently collaborated with mathematician Joseph Sauveur on the education of Philippe, Duke of Chartres, was asked by Chartres to work with Sauveur on a scientific study of acoustics sponsored by the Royal Academy of Science. To measure scientifically the number of beats per second caused by different"
"minute, and since its circumference is divided into 60 parts, the angular motion of one division corresponds to one second. A small window next to the hanging ring reveals a number, which is replaced by another number with each revolution of the dial and indicates the minutes; the Chronograph can run about three-quarters of an hour without stopping. To use this instrument, when it is mounted and in a resting state, one first sets the divisions marking the time to the starting points by turning a knurled knob with one’s hand. Through the intermediary of a gear train, the knob"
"moved from its weighted position to its unweighted position, and the momentary interruption would be recorded on a paper chart. The modern chronograph consists of two sensing areas called ""chronograph screens"", which contain optical sensors that detect the passage of the bullet. The bullet is fired so it passes through both screens, and the time it takes the bullet to travel the distance between the screens is measured electronically. The first electronic ballistic chronograph was invented by Kiryako (""Jerry"") Arvanetakis in the 1950s. As consulting engineer under contract by NACA (later NASA), he was asked to find a way to"