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At one date in the year, the Sun would be directly overhead at the North Pole, so its declination would be +90°. For the next few months, the subsolar point would move toward the South Pole at constant speed, crossing the circles of latitude at a constant rate, so that the solar declination would decrease linearly with time. Eventually, the ...
In astronomy, declination (abbreviated dec; symbol δ) is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination angle is measured north (positive) or south (negative) of the celestial equator , along the hour circle passing through the point in question.
It is the complement to the solar altitude or solar elevation, which is the altitude angle or elevation angle between the sun’s rays and a horizontal plane. [4] [5] At solar noon, the zenith angle is at a minimum and is equal to latitude minus solar declination angle. This is the basis by which ancient mariners navigated the oceans. [6]
Analemma: Equation of time vs. declination of the Sun. Calculated for the year 2020 using the formulas from The Astronomical Almanac for the Year 2019. As often seen on a globe, the analemma is also often plotted as a two-dimensional figure of equation of time vs. declination of the Sun.
The Earth is tilted approximately 23.5 degrees on its axis, and each solstice is dictated by the amount of solar declination, or "the latitude of Earth where the sun is directly overhead at noon ...
The solar azimuth angle is the azimuth (horizontal angle with respect to north) of the Sun's position. [1] [2] [3] This horizontal coordinate defines the Sun's relative direction along the local horizon, whereas the solar zenith angle (or its complementary angle solar elevation) defines the Sun's apparent altitude.
Solar longitude, commonly abbreviated as Ls, is the ecliptic longitude of the Sun, i.e. the position of the Sun on the celestial sphere along the ecliptic. It is also an effective measure of the position of the Earth (or any other Sun-orbiting body) in its orbit around the Sun, [ 1 ] usually taken as zero at the moment of the vernal equinox . [ 2 ]
William Austin Burt's solar compass. Burt's solar compass or astronomical compass/sun compass is a surveying instrument that makes use of the Sun's direction instead of magnetism. William Austin Burt invented his solar compass in 1835. The solar compass works on the principle that the direction to the Sun at a specified time can be calculated ...