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Ordinal Date
An ordinal date is a calendar date typically consisting of a ''year'' and an ''ordinal number'', ranging between 1 and 366 (starting on January 1), representing the multiples of a ''day'', called day of the year or ordinal day number (also known as ordinal day or day number). The two parts of the date can be formatted as "YYYY-DDD" to comply with the ISO 8601 ordinal date format. The year may sometimes be omitted, if it is implied by the context; the day may be generalized from integers to include a decimal part representing a fraction of a day. Nomenclature ''Ordinal date'' is the preferred name for what was formerly called the ''" Julian date"'' or , or , which still seen in old programming languages and spreadsheet software. The older names are deprecated because they are easily confused with the earlier dating system called ' Julian day number' or , which was in prior use and which remains ubiquitous in astronomical and some historical calculations. The U.S. military some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordinated Universal Time
Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communication, navigation, scientific research, and commerce. UTC has been widely embraced by most countries and is the effective successor to Greenwich Mean Time (GMT) in everyday usage and common applications. In specialised domains such as scientific research, navigation, and timekeeping, other standards such as Universal Time, UT1 and International Atomic Time (TAI) are also used alongside UTC. UTC is based on TAI (International Atomic Time, abbreviated from its French name, ''temps atomique international''), which is a weighted average of hundreds of atomic clocks worldwide. UTC is within about one second of mean solar time at 0° longitude, the currently used prime meridian, and is not adjusted for daylight saving time. The coordination of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISO 8601
ISO 8601 is an international standard covering the worldwide exchange and communication of date and time-related data. It is maintained by the International Organization for Standardization (ISO) and was first published in 1988, with updates in 1991, 2000, 2004, and 2019, and an amendment in 2022. The standard provides a well-defined, unambiguous method of representing calendar dates and times in worldwide communications, especially to avoid misinterpreting numeric dates and times when such data is transferred between countries with different conventions for writing numeric dates and times. ISO 8601 applies to these representations and formats: ''dates'', in the Gregorian calendar (including the proleptic Gregorian calendar); ''times'', based on the 24-hour timekeeping system, with optional UTC offset; '' time intervals''; and combinations thereof.ISO 8601:2004 section 1 Scope The standard does not assign specific meaning to any element of the dates/times represented: t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus 1 Releasing Seen From Mission Control (cropped) - Clock Board Detail
Cygnus is the Latin word for swan and may refer to: Astronomy * Cygnus (constellation), a northern constellation ** Cygnus A, a radio galaxy within the constellation ** Cygnus X (star complex), a star complex within the constellation ** Cygnus X-1, a binary system within the constellation ** Cygnus X-3, a binary system within the constellation Business & industry * Cygnus 20, a Canadian sailboat design * ''Cygnus'' (spacecraft), a space vehicle developed by Orbital Sciences Corporation and Thales Alenia Space * Cygnus Air or Gestair Cargo, a Spanish cargo airline * Cygnus Business Media, a U.S.-based business-to-business publishing company * Cygnus Solutions, a company that provided commercial support for free software and the original developer of Cygwin Other uses * ''Cygnus'' (genus), the genus of most swans * Cygnus (mythology) or Cycnus, a number of characters in Greek mythology * Cygnus X-1 (song series), a 1977–1978 two-part song series by Rush * Cygnus X (music g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calendar Date
A calendar date is a reference to a particular day, represented within a calendar system, enabling a specific day to be unambiguously identified. Simple math can be performed between dates; commonly, the number of days between two dates may be calculated, e.g., "25 " is ten days after "15 ". The date of a particular event depends on the time zone used to record it. For example, the air attack on Pearl Harbor that began at 7:48 a.m. local Hawaiian time (HST) on 7 December 1941 is recorded equally as having happened on 8 December at 3:18 a.m. Japan Standard Time (JST). A particular day may be assigned a different nominal date according to the calendar used. The de facto standard for recording dates worldwide is the Gregorian calendar, the world's most widely used civil calendar. Many cultures use religious calendars such as the Gregorian ( Western Christendom, AD), the Julian calendar ( Eastern Christendom, AD), Hebrew calendar (Judaism, AM), the Hijri calendars (Is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Year
A year is a unit of time based on how long it takes the Earth to orbit the Sun. In scientific use, the tropical year (approximately 365 Synodic day, solar days, 5 hours, 48 minutes, 45 seconds) and the sidereal year (about 20 minutes longer) are more exact. The modern calendar year, as reckoned according to the Gregorian calendar, approximates the tropical year by using a system of leap years. The term 'year' is also used to indicate other periods of roughly similar duration, such as the lunar year (a roughly 354-day cycle of twelve of the Moon's phasessee lunar calendar), as well as periods loosely associated with the calendar or astronomical year, such as the seasonal year, the fiscal year, the academic year, etc. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar climate, subpolar regions around the planet, four ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordinal Number
In set theory, an ordinal number, or ordinal, is a generalization of ordinal numerals (first, second, th, etc.) aimed to extend enumeration to infinite sets. A finite set can be enumerated by successively labeling each element with the least natural number that has not been previously used. To extend this process to various infinite sets, ordinal numbers are defined more generally using linearly ordered greek letter variables that include the natural numbers and have the property that every set of ordinals has a least or "smallest" element (this is needed for giving a meaning to "the least unused element"). This more general definition allows us to define an ordinal number \omega (omega) to be the least element that is greater than every natural number, along with ordinal numbers , , etc., which are even greater than . A linear order such that every non-empty subset has a least element is called a well-order. The axiom of choice implies that every set can be well-orde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decimal Part
The fractional part or decimal part of a non‐negative real number x is the excess beyond that number's integer part. The latter is defined as the largest integer not greater than , called ''floor'' of or \lfloor x\rfloor. Then, the fractional part can be formulated as a difference: :\operatorname (x)=x - \lfloor x \rfloor,\; x > 0. The fractional part of logarithms, specifically, is also known as the mantissa; by contrast with the mantissa, the integral part of a logarithm is called its ''characteristic''. The word ''mantissa'' was introduced by Henry Briggs. For a positive number written in a conventional positional numeral system (such as binary or decimal), its fractional part hence corresponds to the digits appearing after the radix point, such as the decimal point in English. The result is a real number in the half-open interval x, -\lfloor , x, \rfloor , or by the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julian Date
The Julian day is a continuous count of days from the beginning of the Julian period; it is used primarily by astronomers, and in software for easily calculating elapsed days between two events (e.g., food production date and sell by date). The Julian period is a chronological interval of 7980 years, derived from three multi-year cycles: the Indiction, Solar, and Lunar cycles. The last year that was simultaneously the beginning of all three cycles was , so that is year 1 of the current Julian period, making AD year of that Period. The next Julian Period begins in the year AD 3268. Historians used the period to identify Julian calendar years within which an event occurred when no such year was given in the historical record, or when the year given by previous historians was incorrect. The Julian day number (JDN) has the same epoch as the Julian period, but counts the number of days since the epoch rather than the number of years since then. Specifically, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (reference Date)
In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by congruity, or by following conventions understood from the epoch in question. The epoch moment or date is usually defined from a specific, clear event of change, an ''epoch event''. In a more gradual change, a deciding moment is chosen when the ''epoch criterion'' was reached. Calendar eras Pre-modern eras * The Yoruba calendar (''Kọ́jọ́dá'') uses 8042 BC as the epoch, regarded as the year of the creation of Ile-Ife by the god Obatala, also regarded as the creation of the earth. * '' Anno Mundi'' it. "Year of the World"(years since the creation of the world) is used in ** the Byzantine calendar (5509 BC). ** the Hebrew calendar (3761 BC). * The Mesoamerican Long Count Calendar uses the creation of the fourth world ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calculating The Day Of The Week
The determination of the day of the week for any date may be performed with a variety of algorithms. In addition, perpetual calendars require no calculation by the user, and are essentially lookup tables. A typical application is to calculate the day of the week on which someone was born or a specific event occurred. Concepts In numerical calculation, the days of the week are represented as weekday numbers. If Monday is the first day of the week, the days may be coded 1 to 7, for Monday through Sunday, as is practiced in ISO 8601. The day designated with 7 may also be counted as ''0'', by applying the arithmetic modulo 7, which calculates the remainder of a number after division by 7. Thus, the number 7 is treated as 0, the number 8 as 1, the number 9 as 2, the number 18 as 4, and so on. If Sunday is counted as day 1, then 7 days later (''i.e.''day 8) is also a Sunday, and day 18 is the same as day 4, which is a Wednesday since this falls three days after Sunday (''i.e.''). Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeller's Congruence
Zeller's congruence is an algorithm devised by Christian Zeller in the 19th century to calculate the day of the week for any Julian or Gregorian calendar date. It can be considered to be based on the conversion between Julian day and the calendar date. Formula For the Gregorian calendar, Zeller's congruence is :h = \left(q + \left\lfloor\frac\right\rfloor + K + \left\lfloor\frac\right\rfloor + \left\lfloor\frac\right\rfloor - 2J\right) \bmod 7, for the Julian calendar it is :h = \left(q + \left\lfloor\frac\right\rfloor + K + \left\lfloor\frac\right\rfloor + 5 - J\right) \bmod 7, where * ''h'' is the day of the week (0 = Saturday, 1 = Sunday, 2 = Monday, ..., 6 = Friday) * ''q'' is the day of the month * ''m'' is the month (3 = March, 4 = April, 5 = May, ..., 14 = February) * ''K'' the year of the century ((adjYear) \bmod 100). (The ''adjYear'' (adjusted year) is explained in the Note below.) * ''J'' is the zero-based century (actually \lfloor (adjYear)/100 \rfloor) For exa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
