Heliocentric coordinates

Japanese: 日心座標 - にっしんざひょう（英語表記）heliocentric coordinates

Coordinates with the center of the sun as the origin. To find the position of a celestial body such as a planet or star as seen from the Earth, first calculate the heliocentric coordinate according to mechanical theory, then subtract the Earth's coordinates to get the geocentric coordinate. Heliocentric coordinates are expressed in two ways: Cartesian and polar. In Cartesian coordinates, the equatorial plane is used as the base, with the direction of the vernal equinox on the X- axis, the direction of 6 o'clock (90°) on the equatorial plane on the Y- axis, and the direction of the North Pole on the Z- axis. In polar coordinates, the ecliptic plane is used as the base, and the longitude is expressed as the ecliptic longitude, with the great circle passing through the vernal equinox and the North Pole of the ecliptic as the origin of longitude, and the latitude is expressed as the ecliptic latitude, with the ecliptic plane as the latitude 0° and the direction of the North Pole as the positive and the direction of the South Pole as the negative, respectively, and the distance from the Sun is expressed as a radius.

Source: Heibonsha World Encyclopedia, 2nd Edition Information

Japanese:

太陽の中心を原点にとった座標。惑星やすい星などの天体の地球から見た位置を求めるには，まず力学理論に従って日心座標を計算し，地球の座標を引いて地心座標にする。日心座標の表現は直交座標と極座標の二つが用いられ，直交座標の場合は春分点の方向をX軸に，赤道面で6時，すなわち90゜の方向をY軸，北極方向をZ軸にとった赤道面基準のものが使用される。極座標では黄道面を基準にとって，春分点と黄道の北極を通る大円を経度の原点にとった経度すなわち黄経と，黄道面を緯度0゜として北極の方向へ＋にとり，南極の方向に－にとった緯度すなわち黄緯と，太陽からの距離を動径と呼んだもので示す。

出典　株式会社平凡社世界大百科事典第２版について　情報

<<: Treaty of Amity between Japan and China

>>: Nisshin Kisen Kaisha