Editing Eclipse cycle (section)

===Repetition of lunar eclipses===
For the repetition of a lunar eclipse, the geometric alignment of the Moon, Earth and Sun, as well as some parameters of the lunar orbit should be repeated. The following parameters and criteria must be repeated for the repetition of a lunar eclipse:
# The Moon must be in full phase.
# The longitude of [[perigee]] or [[apogee]] of the Moon must be the same.
# The longitude of the [[Orbital node|ascending node]] or [[Orbital node|descending node]] must be the same.
# The Earth will be nearly the same distance from the Sun, and tilted to it in nearly the same orientation.
These conditions are related with the three periods of the Moon's orbital motion, viz. the [[synodic month]], [[anomalistic month]] and [[draconic month]]. In other words, a particular eclipse will be repeated only if the Moon will complete roughly an integer number of synodic, draconic, and anomalistic periods (223, 242, and 239) and the Earth-Sun-Moon geometry will be nearly identical to that eclipse. The Moon will be at the same node and the same distance from the Earth. [[Gamma (eclipse)|Gamma]] changes monotonically throughout any single [[Saros (astronomy)|Saros]] series. The change in gamma is larger when Earth is near its aphelion (June to July) than when it is near perihelion (December to January). When the Earth is near its average distance (March to April or September to October), the change in gamma is average.