Cheonmun (천문)
Reading Korea’s Ancient Star Maps
Overview
Cheonmun (天文, heavenly patterns) is the Korean tradition of astronomy-astrology, in which the night sky is mapped into the twenty-eight lunar mansions (이십팔수) grouped under the Azure Dragon, Vermilion Bird, White Tiger, and Black Tortoise of the four directions. Royal astronomers tracked the Moon, planets, comets, and eclipses as omens bearing on the king and the harvest. A Cheonmun reading locates your birth against these mansions and the four celestial palaces, drawing meaning from the constellation the Moon was traversing and the symbolism of its guardian quadrant.
Origin & history
Korean sky-watching reaches back to antiquity: Cheomseongdae, the stone observatory in Gyeongju, was built circa 632–647 CE under Queen Seondeok of Silla and is among the oldest surviving observatories in East Asia. The twenty-eight-mansion (이십팔수) framework, shared across the Sinosphere, was inherited and refined by Korean court astronomers as the backbone of celestial divination.
Goguryeo tomb murals from the 5th–6th centuries depict constellations, and in 1395 the Joseon court carved the Cheonsang Yeolcha Bunyajido, a planispheric star map of some 1,467 stars, into stone for King Taejo. The royal Seowun-gwan observatory bureau logged eclipses, comets, and sunspots for centuries, treating heavenly patterns as guidance for statecraft as much as science.
How it works
Cheonmun divides the ecliptic belt into twenty-eight lunar mansions, each a constellation the Moon lodges in for roughly a night, and assigns them to the four guardian quadrants of the sky. A reading identifies the mansion and palace tied to your birth moment, then interprets the omen-lore attached to that asterism and its directional guardian. The askTIAN API computes the lunar mansion for a given birth date and returns its name (Korean and Hanja), its guardian quadrant, the associated symbolism, and a 0–100 fortune score.
Good for
- Birth-sky readings
- Seasonal timing
- Auspicious-day selection
- Life-direction insight
- Cultural-heritage exploration
- Annual outlooks
Use cases
Natal Mansion Reading
Discover which of the twenty-eight lunar mansions the Moon occupied at your birth and what its omen-lore reveals about your temperament and path.
Date Selection
Identify celestially favourable days for weddings, openings, or travel by matching the mansion governing a chosen date.
Seasonal Forecast
Read the quadrant guardian — Azure Dragon, Vermilion Bird, White Tiger, or Black Tortoise — ruling a coming season for its prevailing influence.
Heritage Discovery
Explore the constellation symbolism preserved by Korea’s royal observatories as a window into traditional cosmology.
Key terms
- Isippalsu (이십팔수)
- The twenty-eight lunar mansions — constellations along the ecliptic that the Moon successively lodges in across a sidereal month.
- Four Symbols (사신)
- The Azure Dragon, Vermilion Bird, White Tiger, and Black Tortoise guarding the eastern, southern, western, and northern quadrants of the sky.
- Cheonsang (천상)
- The celestial image — the configuration of stars and planets read as an omen bearing on human and royal affairs.
- Seongsuk (성수)
- An asterism or lodging-star; the specific constellation whose symbolism anchors a Cheonmun interpretation.
API
The askTIAN Cheonmun API maps a birth date to its lunar mansion and guardian quadrant, returning the mansion name in Korean and Hanja, its symbolism, and a 0–100 fortune score.
Endpoint: POST /trpc/korean.cheonmun — 3 TIAN Points. See the API documentation and Playground.