<Tr> <Th> 2019 </Th> <Td> 20 </Td> <Td> 21: 58 </Td> <Td> 21 </Td> <Td> 15: 54 </Td> <Td> 23 </Td> <Td> 07: 50 </Td> <Td> 22 </Td> <Td> 04: 19 </Td> </Tr> <Tr> <Th> 2020 </Th> <Td> 20 </Td> <Td> 03: 50 </Td> <Td> 20 </Td> <Td> 21: 44 </Td> <Td> 22 </Td> <Td> 13: 31 </Td> <Td> 21 </Td> <Td> 10: 02 </Td> </Tr> <P> An equinox is commonly regarded as the moment in which the plane of Earth's equator passes through the center of the Sun's disk, which occurs twice each year, around 20 March and 23 September . This simplified, but incorrect, understanding of Earth's orbital motion can lead to errors of up to 69 seconds from the actual time of equinox . </P> <P> The instants of the equinoxes are currently defined to occur when the apparent ecliptic longitude of the Sun is either 0 ° or 180 ° . As the true motion of the Earth in its orbit oscillates around the center of mass of the Terra - Luna binary, there are tiny (up to 11⁄4 arcsecond) variations of the Sun's apparent ecliptic latitude, which are discussed in section 1.6, that may mean the Sun's centre is not precisely over the equator at the moment of equinox . </P>

What is the date of the autumnal equinox