Sky Cultures 03

The Moon's Houses

India, China and Arabia each split the Moon's road into 27 or 28 nightly stations — and all three start their stories in the same corner of Taurus.

Working out when this is best placed from where you are…

Latitude

Longitude

Which night

Date

Hour

Used for this lesson only — your map settings, and every other lesson, stay as they are.

Sources

HYG stellar database v4.2 — star positions, magnitudes and every separation quoted here
Plofker, Mathematics in India (Princeton, 2009), ch. 2 — the nakshatras and the Vedic calendar
Taittiriya Samhita 2.3.5 — Soma, the daughters of Prajapati, and Rohini
Mahabharata, Vana Parva, the birth of Skanda — the Seven Sages, their wives and the Krittikas
Shijing, Minor Odes, "Jian jian zhi shi" — the Moon in the Net brings rain
Varisco, "The Origin of the anwāʾ in Arab Tradition", Studia Islamica 74, 5 (1991)
Kunitzsch & Smart, A Dictionary of Modern Star Names (Sky Publishing, 2006) — the Arabic mansions behind our star names
IAU Working Group on Star Names — the catalogue of approved names, with their cultures of origin

← GUIDES

Along the line drawn here the Moon moves about 13° a night, and it comes back to the same star in 27.3 days. So wherever people watched it closely, they counted its nights: 27 or 28 stations on its road, one a night — in India the nakshatras, in China the xiu, to the Arabs the manāzil al-qamar, the Moon's houses. Whether they grew up apart or borrowed is still argued.

The oldest Indian lists, in the Vedas, begin here: the Pleiades are Krittika, the first nakshatra. That start fits the sky of about 2300 BCE, when the spring equinox lay near this cluster; precession has since carried the equinox two whole signs west. The Krittikas are six mothers who nursed the war god Kartikeya, who grew six heads so that none of them would be left out.

Next is Rohini, the red one — Aldebaran and the V of the Hyades. In the Taittiriya Samhita the creator gives his daughters to Soma, the Moon, and Soma lives only with Rohini. The others go home, and the Moon is struck with a wasting sickness, lifted when he promises to visit each wife in turn. Later tellings make the wives the nakshatras, and the sickness his monthly waning.

Later lists start two stations earlier, at Ashvini — the horse-headed twin physicians, in the horns of Aries at Sheratan and Mesarthim — and run round to Revati, the "wealthy", in Pisces, which is still the zero point of the Indian sidereal zodiac. In 2017 the IAU adopted Revati and Bharani, the second station, as the official names of those stars.

China counts 28 lodges, and names these two Mǎo, the Pleiades, and Bì, the Net — the Hyades as a long-handled hunting net, with Aldebaran on its rim. An ode in the Book of Songs says that when the Moon lodges in the Net there will be downpours. Half of Asia's farming calendar is hiding in these few degrees of sky.

The Arabs called the Pleiades al-Thurayyā, "the little crowd", and the star behind them al-Dabarān, "the follower" — our Aldebaran. Every 13 days one house set in the west at dawn as its opposite rose in the east, and each pair, the anwāʾ, was credited with that season's rain, wind or heat. Sheratan and Botein in Aries began the list.

Run an hour and watch the Big Dipper's handle climb in the north-east. In India the Dipper is the Saptarishi, the Seven Sages. In the Mahabharata six of their wives, sent away, became the Krittikas; the seventh stayed. She is Alcor — Arundhati — beside Mizar, the sage Vasishtha; Hindu couples are shown her at their wedding.