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Noon (also midday or noon time) is the hour of 12:00 (11:59AM plus one minute) in an observer's local time zone, or more loosely, a time near the middle of the day when workers in many countries take a meal break. The scientific term solar noon describes the moment when the sun crosses the meridian in apparent solar time, the time during a day with the highest sun elevation, which depends on longitude, latitude and date .

The opposite
Antonym

In lexical semantics, opposites are words that lie in an inherently incompatible binary relationship as in the opposite pairs male : female, long : short, up : down, and precede : follow....
 of noon is midnight
Midnight

Midnight is, literally, "the middle of the night." In most systems it is when one day ends and the next begins: when the date changes. Originally midnight was halfway between sunset and dawn, varying according to the seasons....
.

Etymology
The word "noon" is derived from Latin nona hora, the ninth hour of the day.






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Noon (also midday or noon time) is the hour of 12:00 (11:59AM plus one minute) in an observer's local time zone, or more loosely, a time near the middle of the day when workers in many countries take a meal break. The scientific term solar noon describes the moment when the sun crosses the meridian in apparent solar time, the time during a day with the highest sun elevation, which depends on longitude, latitude and date .

The opposite
Antonym

In lexical semantics, opposites are words that lie in an inherently incompatible binary relationship as in the opposite pairs male : female, long : short, up : down, and precede : follow....
 of noon is midnight
Midnight

Midnight is, literally, "the middle of the night." In most systems it is when one day ends and the next begins: when the date changes. Originally midnight was halfway between sunset and dawn, varying according to the seasons....
.

Etymology


The word "noon" is derived from Latin nona hora, the ninth hour of the day. The Roman and Western European medieval monastic day began at 6:00 am (0600) by modern timekeeping, so the ninth hour starts at what is now 2:00 pm (1400). In English, the meaning of the word shifted to midday by the year 1100 CE.

Solar noon


Solar noon is the moment when the sun appears the highest in the sky
Sky

The sky is the part of the atmosphere or of outer space visible from the surface of any astronomical object. It is difficult to define precisely for several reasons....
 (nearest zenith
Zenith

In broad terms, the zenith is the direction pointing directly above a particular location . Since the concept of being above is itself somewhat vague, scientists define the zenith in more rigorous terms....
), compared to its positions during the rest of the year. It occurs when the Sun is transitting the celestial
Astronomy

Astronomy is the science of Astronomical object and Phenomenon that originate outside the Earth's atmosphere . It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the physical cosmology....
 meridian
Meridian (astronomy)

This article is about the astronomical concept. For other uses of the word, see meridian .In the sky, a meridian is an imaginary great circle on the celestial sphere....
. This is also the origin of the terms ante meridiem
12-hour clock

The 12-hour clock is a time conversion convention in which the 24 hours of the day are divided into two periods called ante meridiem and post meridiem ....
 and post meridiem
12-hour clock

The 12-hour clock is a time conversion convention in which the 24 hours of the day are divided into two periods called ante meridiem and post meridiem ....
 as noted below. The Sun is directly overhead at solar noon at the equator
Equator

The equator is the intersection of the Earth's surface with the Plane perpendicular to the Earth's rotation and containing the Earth's center of mass....
 on the equinox
Equinox

Equinoxes occur twice a year, when the tilt of the Earth's axis is inclined neither away from nor toward the Sun, causing the Sun to be located vertically above a point on the equator....
es; at Tropic of Cancer
Tropic of Cancer

The Tropic of Cancer, or Northern tropic, is one of five major degree measures or major circle of latitude that mark maps of the Earth. It is the northernmost latitude at which the Sun can appear directly overhead at noon....
 (latitude
Latitude

Latitude, usually denoted symbolically by the Greek letter phi gives the location of a place on Earth north or south of the equator. Lines of Latitude are the horizontal lines shown running east-to-west on maps ....
 23° 26' 22? N) on the June solstice
Solstice

A solstice is an astronomical event that occurs twice each year, when the tilt of the Earth's Rotation is most inclined toward or away from the Sun, causing the Sun's apparent position in the sky to reach its north or south extreme....
; and at Tropic of Capricorn
Tropic of Capricorn

The Tropic of Capricorn, or Southern tropic, is one of the five major circle of latitude that mark maps of the Earth. It lies 23degree 26' 22? south of the Equator, and marks the most southerly latitude at which the sun can appear directly overhead at noon....
 (23° 26' 22? S) on the December solstice.

Due to the different locations within a single time zone, it is largely a coincidence that at your particular longitude the instant of solar noon would occur at the local clock time noon - but it does occur at some location within your time zone every day, at a different precise longitude every day.

Nomenclature


With 12-hour time notation, most authorities recommend avoiding confusion by using "noon", "12 noon", or "12:00 noon".

Digital clocks and computers commonly display 12 p.m. for noon. While that phrase may be used practically, it helps to understand that any particular time is actually an instant. The "p.m." shown on clock displays refers to the 12-hour period following the instant of noon, not to the instant itself. In other words, 11:59 a.m. shows until noon; at the instant of noon it flips to 12:00.

In 24-hour time notation, "12:00" and "12:00:00" refer to noon at the middle of a given date.

While computers and digital clocks display "12:00 a.m." and "12:00 p.m.", those notations provide no clear and unambiguous way to distinguish between midnight and noon. It is actually improper to use "a.m." and "p.m." when referring to 12:00. The abbreviation a.m. stands for ante meridiem or before noon and p.m. stands for post meridiem or after noon. Since noon and midnight are neither after noon nor before noon, neither abbreviation is correct. The length of the error is determined by the smallest unit of time — 12:00:01 p.m. would be correctly notated.

Similarly, midnight is both twelve hours before as well as twelve hours after noon, so both are ambiguous as to the date intended.

The most common ways to represent these times are, (a) to use a 24-hour clock (00:00 and 12:00, 24:00), (b) to use "12 noon" or "12 midnight", although unless the person is referring to a general time and not a specific day, "12 midnight" is still ambiguous, (c) to specify midnight as between two successive days or dates (Midnight Saturday/Sunday or Midnight December 14/15), and (d) to use "12:01 p.m." or "11:59 a.m." This final usage is common in the travel industry, especially train and plane schedules, to avoid confusion as to passengers' schedules.

The U.S. Government Printing Office Style Manual recommends that noon is 12 a.m. and midnight is 12 p.m.

See also


  • 12-hour clock
    12-hour clock

    The 12-hour clock is a time conversion convention in which the 24 hours of the day are divided into two periods called ante meridiem and post meridiem ....
  • Dipleidoscope
    Dipleidoscope

    A dipleidoscope is an instrument used to determine true noon. It consists of a small Optical telescope and a Prism that creates a double image of the sun....
  • Midafternoon
  • Midnight
    Midnight

    Midnight is, literally, "the middle of the night." In most systems it is when one day ends and the next begins: when the date changes. Originally midnight was halfway between sunset and dawn, varying according to the seasons....
  • Hour angle
    Hour angle

    In astronomy, the hour angle is one of the coordinates used in the equatorial coordinate system for describing the position of a point on the celestial sphere....
  • Solar azimuth angle
    Solar azimuth angle

    The solar azimuth angle is the azimuth angle of the sun. It is most often defined as the angle between the line from the observer to the sun projected on the ground and the line from the observer due south....


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