A unit used in the measurement of angles, heavily used particularly in astronomy. Due to ancient Babylonian mathematics, we still divide a circle into 360 even units of arc and ...
A table listing specific data of a moving object, as a function of time. Ephemerides usually contain right ascension ("R. A. " in these web pages) and declination ("Decl. " in ...
Determined in principle from the sun's apparent annual motion, ET is the numerical measure of uniform time, which is the independent variable in the gravitational theory of the ...