Abū Isḥāq Ibrāhīm b. Ḥabīb b. Samura b. Jundab al-Fazārī (Ibn al-Nadīm, 2:273; Ibn al-Qifṭī, 77) or Muḥammad b. Ibrāhīm (Ibn al-Qifṭī, 270) (fl. second half of the second/eighth century), was an astronomer and representative of the earliest stage in the history of Arab astronomy. There is no scholarly agreement about whether the two names correspond to two different persons (father and son?) or only one (Muḥammad b. Ibrāhīm). The latter is the hypothesis assumed in this article, following the opinion of Nallino ( ʿIlm