From Babylon to the IAU

The MUL.APIN tablets catalogue the stars; the zodiac is born as farming-calendar bookkeeping along the Sun's path. The Bull, Lion, Scorpion and goat-fish are already there.

The earliest Greek literature already names Orion, the Bears, the Pleiades and Sirius — and ties planting and sailing seasons to their risings.

48 constellations, 1,022 stars, positions and brightnesses — the sky's standard reference for 1,500 years.

In Isfahan, ʿAbd al-Rahman al-Sufi merges Ptolemy with Arab star lore, corrects the data, draws every figure twice (as seen in sky and on globe) — and records a “little cloud” in Andromeda: the first written record of another galaxy. Through Latin translations of his work, Arabic star names spread across Europe's atlases.

The first atlas of the entire sky. Bayer labels each constellation's stars with Greek letters by brightness — Alpha, Beta, Gamma — the system still in use.

The card set illustrated throughout this guide: 32 plates with holes punched at the stars — hold one to a candle and the constellation lights up.

The International Astronomical Union adopts 88 constellations and draws precise boundaries covering every point of sky. Argo is dismantled; the extinct figures (the owl, the balloon, Antinous) are retired.