Sidereal vs. Synodic Motions. Astronomy Education at the University of Nebraska-Lincoln. The University of Nebraska-Lincoln. [22 September 2020]. (原始内容存档于2006-07-11).
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Sidereal vs. Synodic Motions. Astronomy Education at the University of Nebraska-Lincoln. The University of Nebraska-Lincoln. [22 September 2020]. (原始内容存档于2006-07-11).
Equation Of Time. In-The-Sky.org. Dominic Ford. [22 September 2020]. (原始内容存档于2020-05-13).