The Autumn Equinox

Autumnal equinox occurs in September every year, this date in the northern hemisphere marks the official end of summer and beginning of autumn season. It is also called ‘The September equinox’ or ‘Southward equinox’. The word “equinox” originates from Latin ‘aequus’, meaning “equal,” and ‘nox’ meaning “night.” On the day of equinox, both day and night are of roughly equal lengths.

The Autumn Equinox 2023

Sat , 23rd Sep 2023

Astronomically, as the Earth orbits the Sun and is tilted on its axis, the Sun illuminates the northern or southern hemisphere based on where the Earth actually is along its orbital path. However, there are two periods along the year the Sun illuminates both the southern and southern hemispheres in equal durations. These moments or days are called the equinoxes. The Autumnal equinox mark the day or the time in the solar calendar where daylight and night are of equal lengths or almost exactly equal.

The Autumn or the September equinox can occur any day between September 21 and 24. At the equinox, when the Sun viewed from the equator it looks like it rises directly in the east and sets right on in the west. However, because of refraction the Sunset and Sunrise usually appear slightly above the horizon though its "true" midpoint is rising or setting. When viewed at the north or south poles, it moves virtually horizontally on the line or above the horizon, not rising or moving apart from the movement in "declination" of a little under a half i.e -0.39 degree per day. Autumn equinox marks the end of astronomical summertime and the beginning of astronomical autumn season in the Northern Hemisphere. In the Southern Hemisphere this equinox marks the end of astronomical winter and the beginning of astronomical spring called vernal equinox.

The Harvest Moon

The Harvest Moon is the full moon that occurs nearest to the day of autumnal equinox. Historically, the bright moon light of the Harvest Moon was a guiding light for the farmers to work late into the night. This is one of the reasons why this full moon is called The Harvest Moon.