Ibn al‐Ādamī (flourished in

Baghdad Baghdad (; ar, بَغْدَاد , ) is the capital of Iraq and the second-largest city in the Arab world after Cairo. It is located on the Tigris near the ruins of the ancient city of Babylon and the Sassanid Persian capital of Ctesiphon. I ...

, c. 925), was a 10th-century Islamic astronomer who wrote an influential work of

zij A zij ( fa, زيج, zīj) is an Islamic astronomical book that tabulates parameters used for astronomical calculations of the positions of the Sun, Moon, stars, and planets. Etymology The name ''zij'' is derived from the Middle Persian term ' ...

based on Indian sources. The book, now lost, uses the Indian methods found in the ''

Sindhind ''Zīj as-Sindhind'' (, ''Zīj as‐Sindhind al‐kabīr'', lit. "Great astronomical tables of the Sindhind"; from Sanskrit ''siddhānta'', "system" or "treatise") is a work of zij (astronomical handbook with tables used to calculate celestial po ...

''. The 11th-century historian Sa'id al-Andalusi informs us that the theory of

trepidation Trepidation (from Lat. ''trepidus'', "trepidatious"), in now-obsolete medieval theories of astronomy, refers to hypothetical oscillation in the precession of the equinoxes. The theory was popular from the 9th to the 16th centuries. The origin o ...

that became known to Europe and was ascribed to

Thabit ibn Qurra Thabit ( ar, ) is an Arabic name for males that means "the imperturbable one". It is sometimes spelled Thabet. People with the patronymic * Ibn Thabit, Libyan hip-hop musician * Asim ibn Thabit, companion of Muhammad * Hassan ibn Sabit (died 674 ...

can be found instead in the Zij of Ibn al-Adami, who himself may have known of this theory from Thabit's grandon,

Ibrahim ibn Sinan Ibrahim ibn Sinan (Arabic: ''Ibrāhīm ibn Sinān ibn Thābit ibn Qurra'', ; born 295-296 AH/c. 908 AD in Baghdad, died: 334-335 AH/946 AD in Baghdad, aged 38) was a mathematician and astronomer belonging to a family of scholars who originally ha ...

. Ibn al-Adami is also the source for the story of how

Indian astronomy Astronomy has long history in Indian subcontinent stretching from pre-historic to modern times. Some of the earliest roots of Indian astronomy can be dated to the period of Indus Valley civilisation or earlier. Astronomy later developed as a dis ...

reached the court of Caliph

al-Mansur Abū Jaʿfar ʿAbd Allāh ibn Muḥammad al-Manṣūr (; ar, أبو جعفر عبد الله بن محمد المنصور‎; 95 AH – 158 AH/714 CE – 6 October 775 CE) usually known simply as by his laqab Al-Manṣūr (المنصور) w ...

in the early 770s in Baghdad. Presumably, he is the son of Al-Adami.

References

Sources

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10th-century astronomers Astronomers from the Abbasid Caliphate Astronomers of the medieval Islamic world {{Astronomer-stub