An In-Depth Guide to the Zodiac Signs

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From Earth, the sky appears as a vast sphere, with all visible celestial objects projected onto its inner surface—this is the celestial sphere. Like Earth, it has a celestial equator and celestial poles. When observed from Earth’s center, objects on the celestial sphere seem to circle the celestial poles every 24 hours, so the sun, planets, and moons (natural satellites) rise in the east and set in the west.

The celestial equator divides the celestial sphere into two halves: the northern and southern celestial hemispheres. All the celestial objects we can see are arranged across these two hemispheres in 88 constellations. Depending on where most of a constellation’s area lies, it is classified as a northern or southern constellation. By this convention, there are 28 northern constellations, 48 southern constellations, and 12 zodiac constellations.

1. What is the Ecliptic?

Earth orbits the sun once a year. From our perspective, the sun slowly moves eastward among the stars on the celestial sphere, completing a full circle annually—its apparent annual motion. The path of this motion is called the ecliptic. In other words, the plane of Earth’s orbit, extended until it intersects the celestial sphere, traces a great circle known as the ecliptic.

2. What are the Zodiac Signs?

The sun travels along the ecliptic, and the orbital planes of the other planets are tilted only slightly relative to Earth’s orbital plane. This small tilt, called orbital inclination, means the planets’ paths intersect the ecliptic at small angles. Among the nine major planets, except for Pluto, the largest inclination belongs to Mercury at about 7°. Most of the others range between 1° and 3°, while Pluto’s exceeds 17°.

Thus, with the exception of Pluto, the planets always appear close to the ecliptic—generally within about 8° on either side, for a total band some 16° wide. This region is called the zodiacal belt, also known as the belt of the animals. It is the corridor along which the planets of the solar system are seen to move.

From Earth’s viewpoint on the celestial sphere, 13 constellations lie along this zodiacal belt. Starting at the vernal equinox in Pisces, they are Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo (Virgo), Libra, Scorpio, Sagittarius, Capricorn, and Aquarius, collectively known as the twelve zodiac signs. The major planets frequently appear in or pass through these signs and rarely venture into other constellations. Astrologers observe the planets’ positions in these constellations to perform divination and make predictions.

The sizes of the zodiac constellations vary. The largest is Virgo, covering about 1,294 square degrees—more than 1/32 of the total 41,253 square-degree area of the celestial sphere. Leo is also relatively large at about 947 square degrees. The two smallest are Aries and Capricorn, at roughly 441 and 414 square degrees, respectively—less than one-third the size of Virgo.

3. The Twelve Houses of the Zodiac

The ecliptic can be described similarly to Earth’s equator, which uses longitude measured east and west from the Greenwich Observatory in England, set at 0°. Eastward longitudes run from 0° to 180°; westward longitudes run from 0° to 180°, meeting at 180°. Along the ecliptic, we use “ecliptic longitude,” measured from 0° to 360° around the full circle, with 0° set at the vernal equinox—the intersection of the ecliptic and the celestial equator. Although the ecliptic is a perfect 360° circle, the twelve zodiac constellations do not occupy equal spans along it; some are longer, some shorter. The longest is Virgo at about 44°—nearly 1/8 of the ecliptic—while the shortest is Cancer at only about 20°.

The sun moves eastward along the ecliptic at a little under 1° per day. Because the constellations differ in length, the time the sun spends in each also differs, which complicates date-keeping based solely on the sun’s position. To address this, ancient Babylonian astrologers divided the ecliptic into 12 equal segments of 30° each, starting at the vernal equinox. In antiquity, the sun was associated with the god Apollo and imagined to rest in a splendid palace, so each 30° segment was called a “house.” These became the “Twelve Houses of the Zodiac,” with the sun moving through one house per month and completing the 360° circuit each year before returning to the vernal equinox.

When the twelve houses were defined, each corresponded to a zodiac constellation and took its name from it. Due to the precession of the equinoxes, however, the star patterns have gradually shifted westward, significantly changing their ecliptic longitudes. For example, the present-day vernal equinox no longer lies in Aries (though the symbol remains in use) but has shifted into Pisces.

We present the twelve houses of the zodiac below, with their starting and ending ecliptic longitudes, the dates when the sun enters each house (noting that leap years can shift dates by about one day), and the corresponding solar terms:

The Twelve Houses of the Zodiac

House Name Ecliptic Longitude Date of Sun's Entry Solar Term Remarks

Aries 0°～30° March 21 Vernal Equinox First Point of Aries

Taurus 30°～60° April 20 Grain Rain

Gemini 60°～90° May 21 Lesser Grain

Cancer 90°～120° June 22 Summer Solstice First Point of Cancer

Leo 120°～150° July 23 Major Heat

Virgo 150°～180° August 23 End of Heat

Libra 180°～210° September 23 Autumn Equinox First Point of Libra

Scorpio 210°～240° October 23 Frost's Descent

Sagittarius 240°～270° November 22 Light Snow

Capricorn 270°～300° December 22 Winter Solstice First Point of Capricorn

Aquarius 300°～330° January 20 Major Cold

Pisces 330°～0° February 19 Rain Water

4. The Significance of the Twelve Houses in Astrology

First House: Ascendant

Also called the “Rising Sign.” The first house signifies the emergence of self—“I am”—reflecting personality, behavior, health, appearance, physique, and the first impression one makes. In mundane astrology, it represents the “People’s House.”

Second House: House of Wealth

Signifies material possessions and resources—“I have”—including personal finances, attitudes toward money, money management, and owned resources. In mundane astrology, it represents the “Economic House.”

Third House: House of Siblings

Describes one’s immediate environment and basic learning (especially before college), communication skills, short trips, and close-knit relationships with siblings, relatives, and neighbors.

Fourth House: House of Home

Concerns one’s inner emotions and family life, including ancestry, the subconscious, later years, burial matters, and property such as inheritance and real estate. In mundane astrology, it is the “Real Estate House.”

Fifth House: House of Children

Shows one’s approach to love and romance, children, luck in games of chance, leisure activities, and artistic/literary talent and creativity. Because it relates to pure enjoyment, in mundane astrology it is the “House of Entertainment.”

Sixth House: House of Service

Historically connected with servants, it now reflects attitudes toward employees, daily work, involuntary labor and service, subordinates, health, and diet. In mundane astrology, it is the “House of Labor.”

Seventh House: House of Marriage

Addresses one-on-one relationships, including marriage, partnerships, trade, social dealings, contracts, and lawsuits. In mundane astrology, it is the “House of Diplomacy.”

Eighth House: House of Transformation

Relates to “regenerative” matters and what one receives from others, whether tangible or intangible—such as inheritance, insurance, trusts, taxes, and dowries. Because Scorpio’s modern ruler is Pluto, the eighth house also concerns attitudes toward death and mysteries. In mundane astrology, it is the “House of Debt.”

Ninth House: House of Travel

Represents the pursuit of higher understanding, including views on religion, law, and philosophy, as well as long-distance travel, study abroad, and international trade. In mundane astrology, it is the “House of Navigation.”

Tenth House: House of Career

Represents self-actualization and public standing: profession, reputation, entrepreneurship, promotion, authority, and credibility. In mundane astrology, it is the “House of Government and Business.”

Eleventh House: House of Fortune

Concerns one’s approach to groups and communities, social connections, ideals, dreams, and public-welfare activities. In mundane astrology, it is the “House of Parliament.”

Twelfth House: House of Secrets

Represents hidden strengths and vulnerabilities, limitations, secrets, the subconscious, sacrifice, unpaid service, and concealed enemies. In mundane astrology, it is the “House of Welfare.”

5. Four Special Houses

First House (Asc) is the Ascendant or Rising Sign, located at the eastern horizon where the sun rises.
Seventh House (Des) is the Descendant, located at the western horizon where the sun sets.
Tenth House (MC) is the Midheaven or Zenith, located at the top or southern end of the natal chart.
Fourth House (IC), opposite the tenth, is the Nadir, located at the bottom or northern end of the natal chart.

Lingxi Network edited and compiled