⦿ Astrology is an observational discipline, yes, but also a physical one. Flora (plant kingdom) and fauna (animal kingdom), including humankind, respond (e.g. basal metabolic rate, diet, agriculture, migrations, hunting, mating) to the twelve stages of light energy that the sun establishes across the face of the Earth month after month. From sunrise and the culmination of the sun at the highest point of the local sky to sunset and the anti-culmination of the sun at the lowest point. The plane of the local horizon will forever mirror or mimic the plane of the Earth’s equator, for the local horizon is to the observer at a given latitude or city what the equator is to the global observer. The macro perspective according to which the sun rises and falls above (00º Aries) and below (00º Libra) the equator throughout the year becomes the micro perspective according to which the sun rises (appears above the horizon) and sets (disappears below the horizon) throughout the day.

⦿ The segments of our ecliptic (i.e. the signs) constitute months or times of the year, not constellations, although from them they have inherited their names, for there was a time when they coincided with the segments of the ecliptic, that is, the arrival of the sun at each constellation would coincide with its arrival at a segment of the ecliptic (i.e. sign). Due, however, to Earth’s third motion, precession, the constellations no longer coincide with the signs or ecliptic segments.

⦿ The Gregorian calendar, which in 1582 replaced the Julian calendar, recognised this phenomenon, that is to say, the effect of the precession of the equinoxes (spring/autumn), also described as ‘the retrogradation of the vernal point’ (00° Aries, 20 March) or of Easter (religious event) towards an earlier season of the year, winter. While the correction was initially driven by religious considerations, it made the appearance of spring coincide with the last week of March, producing thereby a fundamentally ecliptic, seasonal, or tropical calendar which, by virtue of a more precise rule of leap years, recognises or accounts for the precession of the equinoxes with the utmost accuracy. [1]

⦿ The necessity of or interest in honouring the solar year as seen by an observer upon the Earth does not go back to the Julian and/or Gregorian calendars, but to the Egyptian civilisation.

_________

[1] The current difference between the average Gregorian year (365.2425 days) and the current length of the tropical year (approximately 365.2422 days) is about 0.0003 days per year, or about 26 seconds per year. Over long periods, therefore, this small discrepancy will accumulate and it is estimated that the Gregorian calendar would gain about one day only every 3,236 years relative to the tropical year. The Gregorian calendar is remarkably accurate and will remain closely synchronised with the seasons for many millennia.