Lunation Calendar · — Deep Dives · — Solar Year

A tilted journey

Earth’s axis is tilted by about 23.4 degrees and continues to point in nearly the same direction as Earth travels around the Sun. For part of the orbit, the Northern Hemisphere leans toward the Sun while the Southern Hemisphere leans away; half a year later, their positions reverse. The hemisphere tilted sunward receives longer days and more direct sunlight. This changing angle—not our changing distance from the Sun—is the principal cause of the seasons.

From Earth, the effect appears as a yearly north-and-south migration of the Sun. Its angular position north or south of the celestial equator is called declination. As solar declination changes, so do the height of the Sun’s daily arc and the time it spends above the horizon. The Year Chart’s Seasons Band places those changes within the lunations through which the solar year unfolds.

Four turns of the year

At a solstice, the Sun reaches its northernmost or southernmost declination and reverses direction. These two extremes bring the longest and shortest daylight periods of the year. At an equinox, the Sun crosses the celestial equator, and day and night are nearly equal in length. The two solstices and two equinoxes divide the tropical year into four seasons, with opposite seasons in the two hemispheres.

These are exact astronomical moments, not whole days. They appear as Solstice and Equinox Rare Events and as the boundaries of the Seasons Band. Because a Year Chart follows whole lunations rather than beginning on January 1, those four turns fall wherever their actual times place them within the surrounding Moon cycles.

Twelve stations on the celestial ruler

The tropical zodiac divides the ecliptic into twelve equal signs. As Earth advances in its orbit, the Sun appears to move through this celestial ruler, entering a new sign at each thirty-degree boundary. Each crossing is a solar ingress. The four ingresses into Aries, Cancer, Libra, and Capricorn coincide with the equinoxes and solstices; the other eight divide each season into thirds.

A Sun Ingress Rare Event names the new sign. When that crossing also begins a season, the chart adds its season symbol: spring ❀, summer ☼, fall 🍂︎, or winter ❄︎. The same annual passage appears continuously in the Year Chart’s Sun Zodiac Band. The Astrology Deep Dive explains the zodiac as a coordinate system.

Distance is another rhythm

Earth’s orbit is slightly elliptical, so its distance from the Sun changes. Perihelion is the nearest point and aphelion is the farthest. The Earth Perihelion and Aphelion reference explains how the chart marks these extremes. Distance modestly affects the sunlight Earth receives, but it does not set the seasonal rhythm.

Eight festivals around the wheel

The modern Wheel of the Year places eight festivals around the same solar cycle. Four quarter festivals align with the solstices and equinoxes: Yule, Ostara, Litha, and Mabon. Between them, the cross-quarter festivals Imbolc, Beltane, Lughnasadh, and Samhain mark the intervening forty-five-degree points in the Sun’s annual path. Names and customs vary among traditions; the calendar uses a set common to many modern forms of observance.

The astronomical position locates each festival within the year, but the chart gives it a local, sunset-to-sunset span. The observance begins at the sunset preceding its solar-longitude moment and continues to the following local sunset. The Year Chart’s Wheel of the Year Band shows all eight around the cycle; individual Wheel-of-the-Year Festival Rare Events mark them within a lunation. Because sunset belongs to a place, this cultural boundary also depends on the chart location.