Full moon 29 or 30 days long. A full moon is often thought of as an event of a full night's duration. This is somewhat misleading because its phase seen from Earth continuously waxes or wanes (though much too slowly to notice in real time with the naked eye). Its maximum illumination occurs at the moment waxing has stopped. For any given location, about half of these maximum full moons may be visible, while the other half occurs during the day, when the full moon is below the horizon. Many almanacs list full moons not only by date, but also by their
September equinox end of summer and the beginning of autumn (autumnal equinox) in the Northern Hemisphere, while marking the end of winter and the start of spring (vernal equinox) in the Southern Hemisphere. The September equinox is one point in time commonly used to determine the length of the tropical year. Date and time of the September equinox that occurred from the year 2010 to 2018 (UT) are listed as follows: The point where the Sun crosses the celestial equator southwards is called the first point of Libra. However, due to the precession of the equinoxes, this point is no longer in