Observers witness the brilliant supernova SN 1006

His trigonometric methods enabled quantitative work on arcs, shadows, eclipses and celestial coordinates.

Naubakht and Masha'allah calculated an auspicious horoscope for construction of the Abbasid capital on 30 July 762.

Celestial calculation helped legitimize an imperial city and demonstrates the close historical relationship between astronomy and astrology.

The planners' backgrounds reflect the multilingual and multireligious networks that later supported scholarship in Baghdad.

The city developed institutions where Indian, Persian and Greek materials were translated, criticized and extended in Arabic.

His description included brightness, position and atmospheric effects, providing important evidence from Arabic astronomy.

Modern astronomers identify the expanding remnant of a white-dwarf explosion thousands of light-years away.

Chinese, Japanese, Arabic and European texts show the value of comparing records written for different purposes and audiences.

A modern study identifies his description as the earliest surviving report of Venus passing across the Sun on 24 May 1032.

A Venus transit bears on whether the planet can pass between Earth and the Sun, an issue in medieval planetary ordering.