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Analemmatic Sundial
Analemmatic sundials are a type of horizontal sundial that has a vertical gnomon and hour markers positioned in an elliptical pattern. The gnomon is not fixed and must change position daily to accurately indicate time of day. The time of day is read by the position of the shadow on the ellipse."Analemmatic sundials: How to build one and why they work" C.J. Budd and C.J. Sangwin, maths.org, 1 June 2000 Like most sundials, analemmatic sundials mark rather than clock time. Description An analemmatic sundial is completely defined by: * The size of its ellipse (chosen by the designer). * The |
Calendars
A calendar is a system of organizing days. This is done by giving names to periods of time, typically days, weeks, months and years. A calendar date, date is the designation of a single and specific day within such a system. A calendar is also a physical record (often paper) of such a system. A calendar can also mean a list of planned events, such as a court calendar, or a partly or fully chronological list of documents, such as a calendar of wills. Periods in a calendar (such as years and months) are usually, though not necessarily, synchronized with the cycle of the solar calendar, sun or the lunar calendar, moon. The most common type of pre-modern calendar was the lunisolar calendar, a lunar calendar that occasionally adds one intercalary month to remain synchronized with the solar year over the long term. Etymology The term ''calendar'' is taken from , the term for the first day of the month in the Roman calendar, related to the verb 'to call out', referring to the " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analemma
In astronomy, an analemma (; ) is a diagram showing the position of the Sun in the sky as seen from a fixed location on Earth at the same Solar time#Mean solar time, mean solar time over the course of a year. The change of position is a result of the shifting of the angle in the sky of the path that the Sun takes Celestial sphere, in respect to the stars (the ecliptic). The diagram resembles a lemniscate, figure eight. Globes of the Earth often display an analemma as a two-dimensional figure of equation of time ("sun fast") vs. declination of the Sun. The north–south component of the analemma results from the change in the Sun's declination due to the axial tilt, tilt of Earth's Rotation around a fixed axis, axis of rotation as it orbits around the Sun. The east–west component results from the equation of time, nonuniform rate of change of the Sun's right ascension, governed by the combined effects of Earth's axial tilt and its orbital eccentricity. An analemma can be Phot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solstice
A solstice is the time when the Sun reaches its most northerly or southerly sun path, excursion relative to the celestial equator on the celestial sphere. Two solstices occur annually, around 20–22 June and 20–22 December. In many countries, the seasons of the year are defined by reference to the solstices and the equinoxes. The term ''solstice'' can also be used in a broader sense, as the day when this occurs. For locations not too close to the equator or the poles, the dates with the longest and shortest periods of daylight are the summer and winter solstices, respectively. Terms with no ambiguity as to which hemisphere is the context are "June solstice" and "December solstice", referring to the months in which they take place every year. Etymology The word ''solstice'' is derived from the Latin () and (), because at the solstices, the Sun's declination appears to "stand still"; that is, the seasonal movement of the Sun's sun path, daily path (as seen from Earth) paus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equinox
A solar equinox is a moment in time when the Sun appears directly above the equator, rather than to its north or south. On the day of the equinox, the Sun appears to rise directly east and set directly west. This occurs twice each year, around 20 March and 23 September. An equinox is equivalently defined as the time when the plane of Earth's equator passes through the geometric center of the Sun's disk. This is also the moment when Earth's rotation axis is directly perpendicular to the Sun-Earth line, tilting neither toward nor away from the Sun. In modern times, since the Moon (and to a lesser extent the planets) causes Earth's orbit to vary slightly from a perfect ellipse, the equinox is officially defined by the Sun's more regular ecliptic longitude rather than by its declination. The instants of the equinoxes are currently defined to be when the apparent geocentric longitude of the Sun is 0° and 180°. The word is derived from the Latin ', from ' (equal) and ' ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celestial Equator
The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth. By extension, it is also a plane of reference in the equatorial coordinate system. Due to Earth's axial tilt, the celestial equator is currently inclined by about 23.44° with respect to the ecliptic (the plane of Earth's orbit), but has varied from about 22.0° to 24.5° over the past 5 million years due to Milankovitch cycles and perturbation from other planets. An observer standing on Earth's equator visualizes the celestial equator as a semicircle passing through the zenith, the point directly overhead. As the observer moves north (or south), the celestial equator tilts towards the opposite horizon. The celestial equator is defined to be infinitely distant (since it is on the celestial sphere); thus, the ends of the semicircle always intersect the horizon due east and due west, regardless of the observer's position on Earth. At the poles, the celesti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sine
In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side opposite that angle to the length of the longest side of the triangle (the hypotenuse), and the cosine is the ratio of the length of the adjacent leg to that of the hypotenuse. For an angle \theta, the sine and cosine functions are denoted as \sin(\theta) and \cos(\theta). The definitions of sine and cosine have been extended to any real value in terms of the lengths of certain line segments in a unit circle. More modern definitions express the sine and cosine as infinite series, or as the solutions of certain differential equations, allowing their extension to arbitrary positive and negative values and even to complex numbers. The sine and cosine functions are commonly used to model periodic phenomena such as sound and light waves, the posit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellipse
In mathematics, an ellipse is a plane curve surrounding two focus (geometry), focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. It generalizes a circle, which is the special type of ellipse in which the two focal points are the same. The elongation of an ellipse is measured by its eccentricity (mathematics), eccentricity e, a number ranging from e = 0 (the Limiting case (mathematics), limiting case of a circle) to e = 1 (the limiting case of infinite elongation, no longer an ellipse but a parabola). An ellipse has a simple algebraic solution for its area, but for Perimeter of an ellipse, its perimeter (also known as circumference), Integral, integration is required to obtain an exact solution. The largest and smallest diameters of an ellipse, also known as its width and height, are typically denoted and . An ellipse has four extreme points: two ''Vertex (geometry), vertices'' at the endpoints of the major axis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analemmatic Sundial
Analemmatic sundials are a type of horizontal sundial that has a vertical gnomon and hour markers positioned in an elliptical pattern. The gnomon is not fixed and must change position daily to accurately indicate time of day. The time of day is read by the position of the shadow on the ellipse."Analemmatic sundials: How to build one and why they work" C.J. Budd and C.J. Sangwin, maths.org, 1 June 2000 Like most sundials, analemmatic sundials mark rather than clock time. Description An analemmatic sundial is completely defined by: * The size of its ellipse (chosen by the designer). * The |
Reloj Analemático Faro Barbate - IMG 20230212 151523
"Reloj" () is a song recorded by Puerto Rican singer Rauw Alejandro and Puerto Rican rapper Anuel AA for Alejandro's debut studio album, ''Afrodisíaco'' (2020). It was written by Alejandro, Yampi, Luis Guillermo Marval Camerom, Nesty, Anuel AA, Caleb Calloway, Kenobi, Colla, and Eric Duars, while the production was handled by Calloway and Nesty. The song was released for digital download and streaming by Sony Music Latin and Duars Entertainment on October 22, 2020, as the fourth single from the album. A Spanish language melodic reggaeton song with urban rhythms, it is about the sexual desire the singers feel towards a girl, describing everything they would do to her if the clock had more hours. "Reloj" received positive reviews from music critics, who complimented its rhythms. The track was nominated for Viral Anthem at the 2021 MTV Millennial Awards. It was commercially successful, reaching the top 10 in several Latin American countries, including Colombia and Mexico, and on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analemma
In astronomy, an analemma (; ) is a diagram showing the position of the Sun in the sky as seen from a fixed location on Earth at the same Solar time#Mean solar time, mean solar time over the course of a year. The change of position is a result of the shifting of the angle in the sky of the path that the Sun takes Celestial sphere, in respect to the stars (the ecliptic). The diagram resembles a lemniscate, figure eight. Globes of the Earth often display an analemma as a two-dimensional figure of equation of time ("sun fast") vs. declination of the Sun. The north–south component of the analemma results from the change in the Sun's declination due to the axial tilt, tilt of Earth's Rotation around a fixed axis, axis of rotation as it orbits around the Sun. The east–west component results from the equation of time, nonuniform rate of change of the Sun's right ascension, governed by the combined effects of Earth's axial tilt and its orbital eccentricity. An analemma can be Phot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
