Abstract

The date of an equinox, when the Sun crosses the Equator, cannot be determined by direct observation except from the Equator. The date of an Equalnight, which is 12.0 hours long, can be determined by direct observation of the Sun and stars, everywhere except in a four degree band that straddles the Equator. The Equalnights South of the Equator have dates different from those North of the Equator, due to refraction of low angle light by the atmosphere, and the width of the Sun's disk. Between AD 1488 and 1522 several European navigator/explorers sailed around the South tips of Africa and South America. They navigated by the Sun and stars. Evidently they discovered the Equalnight date differences. The date at which to celebrate Easter was in question. Six Popes struggled for 40 years to rectify the calendrical problem. There were two problems: to bring the calendar back into phase with the motions of the Sun and Moon; to fix the date of Easter everywhere on Earth. The subsequent papal bull of Gregory XIII, in 1582, stated, in part: II. . . . concerns the annual recurrence of Easter and other festivals, which depend upon measurement of motions of the sun and moon. IV. This fact (that the date of Easter is out of phase with the annual motions of the sun and moon), that indisputably requires that calendar restoration be fixed by law, . . . up to now couldn't be done, . . . and did not preserve uninjured the ancient rites of the Church (that was the first concern in this restoration). As a result, dictionaries in most European languages contain definitions equivalent to the following from OED and Merriam-Webster: equinox - either of two times of each year (about 21 March and 23 September) when the sun crosses the equator and the day and night are equal in length all over the world. But there is no date on which the day and night are equal in length all over the world. The durations of day/night on an equinox vary from 12h07m/11h53m at the equator to 24h00m/00h00m at the poles. At the SUN TEMPLE near Majorville the day/night durations at an equinox are 12h10m/11h50m. These dates are not marked in the 4500 year old calendar. But the dates of the 12.0h day/12.0h night are marked unambiguously. Two of the several Equalnight Sun Set and Rise lines will be shown, with a series of Sets and Rises passing through them. The 4000 year old calendar in Stonehenge also marks the Equalnights. These discoveries will result in corrections to definitions of 'equinox' in all European languages, and will introduce two new words, Equalday and Equalnight.