Our two luminaries, the sun and moon, share a similar form-in-time, as the seasonal year and the monthly phases of the moon. The form they share is of two extremes of opposite character, and two midpoints between these.
The Solar Extremes: At the solar extremes, the sun rises high in midsummer day and rises to a much lower point in midwinter day, extreme points at which the sun moves very slowly day-by-day these hence called solstices from the Latin, “sun stands still”.
The Lunar Extremes: These are the full moon, meaning its face is completely illuminated by the sun, and the dark moon, when the moon stands by and in front of the sun and so its face is not illuminated but during a rare solar eclipse, the dark disk of the moon can be seen slowly crossing the sun’s face since the moon moves 12.368 times faster than the sun that defines each day.
The Solar Midpoints: These occur when the sun rises exactly east and sets directly west, everywhere on the earth. These moments are called Equinox because the length of the day then equals (in Latin: “equi”) and the length of the night (in Latin, “nox”). In the year these two equinoxes are called Spring, when light and heat from the sun are growing (waxing), and Autumn, when light and heat are diminishing (waning).
The Lunar Midpoints: Like the sun, these are exactly between its extremes, when exactly half the moon’s face is illuminated. In the morning, as the full moon approaches the sun, its gibbous (less-than-circular) face is waning until it reaches the point of half illumination by the sun. In contrast, the dark moon reappears as a crescent moon, pulling away from the sun setting in the evening.
The common factor between the midpoints of both sun and moon is that this is when time begins, in the sense that, at two equinoxes and at the two half-moons, (a) the sun’s daily sunrise on the horizon is moving fastest and (b) The sun’s illumination of the moon is changing most quickly. In both cases, this allowed the megalithic to accurately start and finish their counting of these time cycles of the year and the month. In both cases, midpoints could most accurately define the day on which an event occurred.
The following post takes this further.