Changes

==Origin==

==Origin==

Medieval Latin ''culminatus'', past participle of ''culminare'', from Late Latin, to crown, from [[Latin]] ''culmin''-, ''culmen'' top

Medieval Latin ''culminatus'', past participle of ''culminare'', from Late Latin, to crown, from [[Latin]] ''culmin''-, ''culmen'' top

*[http://en.wikipedia.org/wiki/17th_century 1647]

*[https://en.wikipedia.org/wiki/17th_century 1647]

==Definitions==

==Definitions==

*1:of a [[celestial]] body : to reach its highest [http://en.wikipedia.org/wiki/Altitude altitude]; also : to be directly overhead

*1:of a [[celestial]] body : to reach its highest [https://en.wikipedia.org/wiki/Altitude altitude]; also : to be directly overhead

*2a : to rise to or form a [[summit]]  

*2a : to rise to or form a [[summit]]  

:b : to reach the highest or a [[climactic]] or decisive [[point]]  

:b : to reach the highest or a [[climactic]] or decisive [[point]]  

<center>For lessons on the [[topic]] of '''''Culmination''''', follow [https://nordan.daynal.org/wiki/index.php?title=Category:Culmination '''''this link'''''].</center>

<center>For lessons on the [[topic]] of '''''Culmination''''', follow [https://nordan.daynal.org/wiki/index.php?title=Category:Culmination '''''this link'''''].</center>

==Description==

==Description==

In [[astronomy]], the '''culmination''' of a [[planet]], [[star]], [http://en.wikipedia.org/wiki/Constellation constellation], etc. is the altitude (or elevation angle) reached when the object transits over an [[observer]]'s [http://en.wikipedia.org/wiki/Meridian_(astronomy) meridian].

In [[astronomy]], the '''culmination''' of a [[planet]], [[star]], [https://en.wikipedia.org/wiki/Constellation constellation], etc. is the altitude (or elevation angle) reached when the object transits over an [[observer]]'s [https://en.wikipedia.org/wiki/Meridian_(astronomy) meridian].

During a [http://en.wikipedia.org/wiki/Sidereal_day sidereal day], an astronomical object will cross the meridian twice: once at its upper culmination, when it is at its highest point as seen from the [[earth]], and once at its lower culmination, its lowest point. Often, culmination is used to mean upper culmination.

During a [https://en.wikipedia.org/wiki/Sidereal_day sidereal day], an astronomical object will cross the meridian twice: once at its upper culmination, when it is at its highest point as seen from the [[earth]], and once at its lower culmination, its lowest point. Often, culmination is used to mean upper culmination.

The altitude of an object in degrees at its upper culmination is equal to (90 − L + D), where L is the [[observer]]'s [[latitude]] and D is the object's [http://en.wikipedia.org/wiki/Declination declination].

The altitude of an object in degrees at its upper culmination is equal to (90 − L + D), where L is the [[observer]]'s [[latitude]] and D is the object's [https://en.wikipedia.org/wiki/Declination declination].

Generally, the [[sun]] is visible at its upper culmination (at noon) and not visible at its lower culmination (at midnight). But during winter near the [http://en.wikipedia.org/wiki/North_Pole North Pole], the sun is below the [[horizon]] at both of its culminations. In most of the northern hemisphere, [http://en.wikipedia.org/wiki/Polaris Polaris], the "North Star", and the rest of the stars of the constellation [http://en.wikipedia.org/wiki/Ursa_Minor Ursa Minor] can be seen to rotate around the [http://en.wikipedia.org/wiki/Celestial_pole celestial pole] and are all visible at both culminations, as long as the sky is [[dark]] enough. Such stars, which never set at the [[observer]]'s location are described as being [http://en.wikipedia.org/wiki/Circumpolar_star circumpolar].

Generally, the [[sun]] is visible at its upper culmination (at noon) and not visible at its lower culmination (at midnight). But during winter near the [https://en.wikipedia.org/wiki/North_Pole North Pole], the sun is below the [[horizon]] at both of its culminations. In most of the northern hemisphere, [https://en.wikipedia.org/wiki/Polaris Polaris], the "North Star", and the rest of the stars of the constellation [https://en.wikipedia.org/wiki/Ursa_Minor Ursa Minor] can be seen to rotate around the [https://en.wikipedia.org/wiki/Celestial_pole celestial pole] and are all visible at both culminations, as long as the sky is [[dark]] enough. Such stars, which never set at the [[observer]]'s location are described as being [https://en.wikipedia.org/wiki/Circumpolar_star circumpolar].

These three examples illustrate all three cases, dependent on the latitude of the observer and the declination of the celestial body.

These three examples illustrate all three cases, dependent on the latitude of the observer and the declination of the celestial body.

*the object is above the horizon even at its lower culmination: it is circumpolar; i.e. if |declination + latitude| > 90° (i.e. if in [http://en.wikipedia.org/wiki/Absolute_value absolute value] the declination is more than the colatitude, in the corresponding hemisphere)

*the object is above the horizon even at its lower culmination: it is circumpolar; i.e. if |declination + latitude| > 90° (i.e. if in [https://en.wikipedia.org/wiki/Absolute_value absolute value] the declination is more than the colatitude, in the corresponding hemisphere)

*the object is below the horizon even at its upper culmination; i.e. if |declination − latitude| > 90° (i.e. if in absolute value the declination is more than the colatitude, in the opposite hemisphere)

*the object is below the horizon even at its upper culmination; i.e. if |declination − latitude| > 90° (i.e. if in absolute value the declination is more than the colatitude, in the opposite hemisphere)

*the upper culmination is above, and the lower below the horizon, so the body is observed to rise and set daily; in the other cases (i.e. if in absolute value the declination is less than the colatitude)

*the upper culmination is above, and the lower below the horizon, so the body is observed to rise and set daily; in the other cases (i.e. if in absolute value the declination is less than the colatitude)

The third case applies for objects in a part of the full sky equal to the cosine of the [[latitude]] (at the [[equator]] it applies for all objects, the [[sky]] turns around the horizontal north-south line; at the poles it applies for none, the sky turns around the vertical line). The first and second case each apply for half of the remaining sky.

The third case applies for objects in a part of the full sky equal to the cosine of the [[latitude]] (at the [[equator]] it applies for all objects, the [[sky]] turns around the horizontal north-south line; at the poles it applies for none, the sky turns around the vertical line). The first and second case each apply for half of the remaining sky.

The time from one upper culmination to the next is approximately 24 hours, and from an upper to a lower culmination is approximately 12 hours. The movement of the [[Earth]] on its [[orbit]] and proper motion of the celestial body affect the time between successive upper culminations of the body. Because of the proper and improper motions of the [[sun]], one solar day (the time between two upper culminations of the sun) is longer than one [http://en.wikipedia.org/wiki/Sidereal_day sidereal day] (the time between two like culminations of any fixed star). The mean difference is 1/365.24219 because the Earth needs 365.24219 days for its orbit around the Sun. (see also sidereal day)

The time from one upper culmination to the next is approximately 24 hours, and from an upper to a lower culmination is approximately 12 hours. The movement of the [[Earth]] on its [[orbit]] and proper motion of the celestial body affect the time between successive upper culminations of the body. Because of the proper and improper motions of the [[sun]], one solar day (the time between two upper culminations of the sun) is longer than one [https://en.wikipedia.org/wiki/Sidereal_day sidereal day] (the time between two like culminations of any fixed star). The mean difference is 1/365.24219 because the Earth needs 365.24219 days for its orbit around the Sun. (see also sidereal day)

[[Category: Astronomy]]

[[Category: Astronomy]]