Full moon (this usage has been noted as "erroneous" by "Sky & Telescope" in 1999). According to either definition, "blue moons" occur with the average frequency of intercalary months, seven times in 19 years, the "Farmers' Almanac" system of "full moon names" effectively defining a lunisolar calendar. Full moon The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon (more exactly, when the ecliptic longitudes of the Sun and Moon differ by 180°). This means that the lunar hemisphere facing Earth – the near
Equinox equinoxes shift through the constellations as follows (expressed in astronomical year numbering when the year 0 = 1 BC, −1 = 2 BC, etc.): The equinoxes are sometimes regarded as the start of spring and autumn. A number of traditional harvest festivals are celebrated on the date of the equinoxes. Observations of the equinox are frequently used in online debates between flat-earth conspiracy proponents and those who support the generally accepted heliocentric globe model. Wolfie6020, a well-known flat-earth debunker on YouTube, has a semi-annual Equinox Challenge with prizes available to any flat-earther who can show a functioning flat-earth model that