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Noon
Noon (or midday) is 12 o'clock in the daytime. It is written as 12 noon, 12:00 m. (for meridiem, literally 12:00 noon), 12 p.m. (for post meridiem, literally "after noon"), 12 pm, or 12:00 (using a 24-hour clock) or 1200 ( military time). Solar noon is the time when the Sun appears to contact the local celestial meridian. This is when the Sun reaches its apparent highest point in the sky, at 12 noon apparent solar time and can be observed using a sundial. The local or clock time of solar noon depends on the longitude and date, with Daylight Savings Time tending to place solar noon closer to 1:00pm. Etymology The word ''noon'' is derived from Latin ''nona hora'', the ninth canonical hour of the day, in reference to the Western Christian liturgical term none, one of the seven fixed prayer times in traditional Christian denominations. The Roman and Western European medieval monastic day began at 6:00 a.m. (06:00) at the equinox by modern timekeeping, so the ninth hour ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sundial
A sundial is a horological device that tells the time of day (referred to as civil time in modern usage) when direct sunlight shines by the apparent position of the Sun in the sky. In the narrowest sense of the word, it consists of a flat plate (the ''dial'') and a gnomon, which casts a shadow onto the dial. As the Sun appears to move through the sky, the shadow aligns with different hour-lines, which are marked on the dial to indicate the time of day. The ''style'' is the time-telling edge of the gnomon, though a single point or ''nodus'' may be used. The gnomon casts a broad shadow; the shadow of the style shows the time. The gnomon may be a rod, wire, or elaborately decorated metal casting. The style must be parallel to the axis of the Earth's rotation for the sundial to be accurate throughout the year. The style's angle from horizontal is equal to the sundial's geographical latitude. The term ''sundial'' can refer to any device that uses the Sun's altitude or azi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
12-hour Clock
The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. (from Latin , translating to "before midday") and p.m. (from Latin , translating to "after midday"). For different opinions on representation of midday and midnight, see #Confusion at noon and midnight Each period consists of 12 hours numbered: 12 (acting as 0), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11. The daily cycle starts at 12 midnight, runs through 12 noon, and continues until just before midnight at the end of the day. There is no widely accepted convention for how midday and midnight should be represented. The 12-hour clock was developed from the second millennium BC and reached its modern form in the 16th century AD. The 12-hour time convention is common in several English-speaking nations and former British colonies, as well as a few other countries. History and use The natural day-and-night division of a calendar day forms the fundamental basis as to why ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun Transit Time
Noon (or midday) is 12 o'clock in the daytime. It is written as 12 noon, 12:00 m. (for meridiem, literally 12:00 noon), 12 p.m. (for post meridiem, literally "after noon"), 12 pm, or 12:00 (using a 24-hour clock) or 1200 (military time). Solar noon is the time when the Sun appears to contact the local celestial meridian. This is when the Sun reaches its apparent highest point in the sky, at 12 noon apparent solar time and can be observed using a sundial. The local or clock time of solar noon depends on the longitude and date, with Daylight Savings Time tending to place solar noon closer to 1:00pm. Etymology The word ''noon'' is derived from Latin ''nona hora'', the ninth canonical hour of the day, in reference to the Western Christian liturgical term none, one of the seven fixed prayer times in traditional Christian denominations. The Roman and Western European medieval monastic day began at 6:00 a.m. (06:00) at the equinox by modern timekeeping, so the ninth hour s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liturgy Of The Hours
The Liturgy of the Hours (Latin: ''Liturgia Horarum'') or Divine Office (Latin: ''Officium Divinum'') or ''Opus Dei'' ("Work of God") are a set of Catholic prayers comprising the canonical hours, often also referred to as the breviary, of the Latin Church. The Liturgy of the Hours forms the official set of prayers "marking the hours of each day and sanctifying the day with prayer." The term "Liturgy of the Hours" has been retroactively applied to the practices of saying the canonical hours in both the Christian East and West–particularly within the Latin liturgical rites–prior to the Second Vatican Council, and is the official term for the canonical hours promulgated for usage by the Latin Church in 1971. Before 1971, the official form for the Latin Church was the ''Breviarium Romanum'', first published in 1568 with major editions through 1962. The Liturgy of the Hours, like many other forms of the canonical hours, consists primarily of psalms supplemented by hymns, re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fixed Prayer Times
Fixed prayer times, praying at dedicated times during the day, are common practice in major world religions such as Judaism, Christianity, and Islam. Judaism Jewish law requires Jews to pray thrice a day; the morning prayer is known as Shacharit, the afternoon prayer is known as Mincha, and the evening prayer is known as Maariv. According to Jewish tradition, the prophet Abraham introduced Shacharit, the prophet Isaac introduced Mincha, and the prophet Jacob introduced Maariv. Jews historically prayed in the direction of the Temple of Solomon in Jerusalem, where the "presence of the transcendent God (''shekinah'') esidedin the Holy of Holies of the Temple". In the Bible, it is written that when the prophet Daniel was in Babylon, he "went to his house where he had windows in his upper chamber open to Jerusalem; and he got down upon his knees three times a day and prayed and gave thanks before his God, as he had done previously" (cf. ). After its destruction, Jews continue to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roman Timekeeping
In Roman timekeeping, a day was divided into periods according to the available technology. Initially the day was divided into two parts: the ''ante meridiem'' (before noon) and the ''post meridiem'' (after noon). With the advent of the sundial circa 263 BC, the period of the natural day from sunrise to sunset was divided into twelve hours. Variation An hour was defined as one twelfth of the daytime, or the time elapsed between sunset and sunrise. Since the duration varied with the seasons, this also meant that the length of the hour changed. Winter days being shorter, the hours were correspondingly shorter and vice versa in summer. At Mediterranean latitude, one hour was about 45 minutes at the winter solstice, and 75 minutes at summer solstice. The Romans understood that as well as varying by season, the length of daytime depended on latitude. Subdivision of the day and night Civil day The civil day (''dies civilis'') ran from midnight (''media nox'') to midnight. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
24-hour Clock
The modern 24-hour clock, popularly referred to in the United States as military time, is the convention of timekeeping in which the day runs from midnight to midnight and is divided into 24 hours. This is indicated by the hours (and minutes) passed since midnight, from 0(:00) to 23(:59). This system, as opposed to the 12-hour clock, is the most commonly used time notation in the world today,See the Common Locale Data Repository for detailed data about the preferred date and time notations used across the world, as well the locale settings of major computer operating systems, and the article Date and time representation by country. and is used by the international standard ISO 8601.International Standard ISO 8601: Data elements and interchange formats – Information interchange – Representation of dates and times. International Organization for Standardization, 3rd ed., 2004. A number of countries, particularly English-speaking, use the 12-hour clock, or a mixture of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (astronomy)
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Zone
A time zone is an area which observes a uniform standard time for legal, commercial and social purposes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because it is convenient for areas in frequent communication to keep the same time. All time zones are defined as offsets from Coordinated Universal Time (UTC), ranging from UTC−12:00 to UTC+14:00. The offsets are usually a whole number of hours, but a few zones are offset by an additional 30 or 45 minutes, such as in India, South Australia and Nepal. Some areas of higher latitude use daylight saving time for about half of the year, typically by adding one hour to local time during spring and summer. List of UTC offsets In the table below, the locations that use daylight saving time (DST) are listed in their UTC offset when DST is ''not'' in effect. When DST is in effect, approximately during spring and summer, their UTC offset is inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daytime
Daytime as observed on Earth is the period of the day during which a given location experiences natural illumination from direct sunlight. Daytime occurs when the Sun appears above the local horizon, that is, anywhere on the globe's hemisphere facing the Sun. In direct sunlight the movement of the sun can be recorded and observed using a sundial that casts a shadow that slowly moves during the day. Other planets and natural satellites that rotate relative to a luminous primary body, such as a local star, also experience daytime, but this article primarily discusses daytime on Earth. Characteristics Approximately half of Earth is illuminated at any time by the Sun. The area subjected to direct illumination is almost exactly half the planet; but because of atmospheric and other effects that extend the reach of indirect illumination, the area of the planet covered by either direct or indirect illumination amounts to slightly more than half the surface. The hemisphere of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Solar Time
Solar time is a calculation of the passage of time based on the position of the Sun in the sky. The fundamental unit of solar time is the day, based on the synodic rotation period. Two types of solar time are apparent solar time (sundial time) and mean solar time (clock time). Introduction A tall pole vertically fixed in the ground casts a shadow on any sunny day. At one moment during the day, the shadow will point exactly north or south (or disappear when and if the Sun moves directly overhead). That instant is local apparent noon, or 12:00 local apparent time. About 24 hours later the shadow will again point north–south, the Sun seeming to have covered a 360-degree arc around Earth's axis. When the Sun has covered exactly 15 degrees (1/24 of a circle, both angles being measured in a plane perpendicular to Earth's axis), local apparent time is 13:00 exactly; after 15 more degrees it will be 14:00 exactly. The problem is that in September the Sun takes less time (as m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can also be used for any other celestial body that is roughly spherical. In spatial (3D) geometry, as applied in astronomy, the equator of a rotating spheroid (such as a planet) is the parallel (circle of latitude) at which latitude is defined to be 0°. It is an imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane perpendicular to its axis of rotation and midway between its geographical poles. On and near the equator (on Earth), noontime sunlight appears almost directly overhead (no more than about 23° from the zenith) every day, year-round. Consequently, the equator has a rather stable daytime temperature throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
