|Died||23 October 1134
|Era||Islamic Golden Age|
|Region||Al-Andalus, Tunisia, Egypt, Palermo|
|Main interests||Quadrivium, Astronomy, Music|
Abū al‐Ṣalt, Umayya ibn ʿAbd al‐ʿAzīz ibn Abī al‐Ṣalt al‐Dānī al‐Andalusī (c. 1068 – 23 October 1134) was an Andalusian polymath whose works on astronomical instruments were read both in the Islamic world and Europe. He also worked as a physician, a teacher of alchemy, and wrote treatises on medicine, philosophy, music, and history. He became well known in Europe through translations of his works made in the Iberian Peninsula and in southern France. He is also credited with introducing Andalusian music to Tunis, which later led to the development of the Tunisian ma'luf.
Abu al-Salt was born in Denia, al-Andalus. After the death of his father while he was a child, he became a student of al‐Waqqashi (1017–1095) of Toledo (a colleague of Al-Zarqali). Upon completing his mathematical education in Seville, and because of the continuing conflicts during the reconquista, he set out with his family to Alexandria and then Cairo in 1096.
In Cairo, he entered the service of the Fatimid ruler Abū Tamīm Ma'add al-Mustanṣir bi-llāh and the Vizier Al-Afdal Shahanshah. His service continued until 1108, when, according to Ibn Abī Uṣaybiʿa, his attempt to retrieve a very large Felucca laden with copper, that had capsized in the Nile River, ended in failure. Abu al-Salt had built a mechanical tool to retrieve the Felucca, and was close to success when the machine's silk ropes fractured. The Vizier Al-Afdal ordered Abu al-Salt's arrest, and he was imprisoned for more than three years, only to be released in 1112.
Abu al-Salt then left Egypt for Kairouan in Tunisia, where he entered the service of the Zirids in Ifriqiya. He also occasionally traveled to Palermo and worked in the court of Roger I of Sicily as a visiting physician. He died in Bejaia, Algeria.
Abu al-Salt wrote an encyclopedic work of many treatises on the scientific disciplines known as quadrivium. This work was probably known in Arabic as Kitāb al‐kāfī fī al‐ʿulūm. His interests also included alchemy as well as the study of medicinal plants. He was keen to discover an elixir able to transmute copper into gold and tin into silver.
- Risāla fī al-amal bi‐l‐astrulab ("On the construction and use of the astrolabe")
- A description of the three instruments known as the Andalusian equatoria.
- Ṣifat ʿamal ṣafīḥa jāmiʿa taqawwama bi‐hā jamīʿ al‐kawākib al‐sabʿa ("Description of the construction and Use of a Single Plate with which the totality of the motions of the seven planets"), where the seven planets refer to Mercury, Venus, earth, Moon, Mars, Jupiter, and Saturn.
- Kitāb al‐wajīz fī ʿilm al‐hayʾa ("Brief treatise on cosmology")
- Ajwiba ʿan masāʾil suʾila ʿan‐ha fa‐ajāba or Ajwiba ʿan masāʾil fī al‐kawn wa‐ʾl‐ḥabīʿa wa‐ʾl‐ḥisāb ("Solution to questions on cosmology, physics, and arithmetic").
- An introduction to astronomy.
See also 
- Comes, Mercè (2007). "Abū al‐Ṣalt: Umayya ibn ʿAbd al‐ʿAzīz ibn Abī al‐Ṣalt al‐Dānī al‐Andalusī". In Thomas Hockey et al. The Biographical Encyclopedia of Astronomers. New York: Springer. pp. 9–10. ISBN 978-0-387-31022-0. (PDF version)