This is the earliest dated Islamic astrolabe, for whilst several earlier Abbasid instruments survive all are undated. The maker's full name is Muhammad ibn 'Abdallah known as Nastulus, this is found in the manuscript sources. Nastulus is also known to have devised several varieties of astrolabes and eclipse calculators. The 10th century bibliographer Ibn al-Nadim mentions him as one of the leading astrolabists of his time, and it is clear that he worked in Baghdad. Other early Islamic astrolabes had several plates, in an attempt to make the instrument "universal". On this astrolabe there is, however, no room for more than the one plate. The throne and rim are cast in one and has three shallow lobes and a small hole on each of the suspensory apparatus, the latter, a neat shackle with trowel-shaped arms and a circular ring.