Journal for the History of Astronomy 1–18 © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0021828615589484 jha.sagepub.com JHA Al-Asf ī ’s Description of the Zāwiya Nasiriyya: The Use of Buildings as Astronomical Tools Mònica Rius-Piniés and Roser Puig-Aguilar University of Barcelona, Spain Abstract Early Arabic sources report the existence of giant astronomical devices housed inside buildings which were used for observational and computational purposes. Some of them are known to us, but their chronology and their relationship to other well-oriented devices in the Islamic or even in the Latin milieu are yet to be explored in depth. This paper aims to establish whether the zāwiya Nāṣiriyya in Tamegroute (Tamgrūt, in the Drâa valley) described by al-Asf ī (seventeenth to eighteenth century) can be considered as part of this tradition. Keywords Giant instruments, observatories, mosques, zāwiya, lighting solar effects, Morocco Preliminaries Arabic sources record references to early celestial observations in the Islamic East. These observations were made in observation posts more than in official observatories, which did not emerge in the region until the thirteenth century. 1 Some of these observation posts were set up in the open air, in public, or private locations; others were housed inside buildings and functioned by using the effects of the Sun’s rays. In the ninth century, privately owned posts, like the one belonging to Ahmad al-Nihawandī, who observed the motion of the sun in Jundishāpūr in Persia in 800, over- lapped in time with the early astronomical programme sponsored by al-Ma’mūn in the al-Shammāsiyya quarter in Baghdad and in the outskirts of Damascus, at the Dayr Murrān monastery on Mount Qāsiyūn. Al-Ma’mūn sponsored a programme of observa- tions which does not seem to have been carried out in buildings devoted to this aim, but Corresponding author: Mònica Rius-Piniés, University of Barcelona, Gran Via 585, 08007 Barcelona, Spain. Email: monica_rius@ub.edu 589484JHA 0 0 10.1177/0021828615589484Journal for the History of AstronomyRius-Pinies and Puig research-article 2015 Article