Abd al-A'imma astrolabe, Oxford inventory 37321

Historical significance

• Oxford's historical astrolabe catalogue attributes inventory 37321 to ‘Abd al-A’imma, gives Isfahan as its place and dates it approximately to 1715. It transcribes the signature on the back as ‘Made by ʿAbd al-Aʾimmah’. This is a different object from Saint Louis 41:1926, whose record assigns that name to the decoration rather than manufacture.
• The mater and limb are described as one-piece brass construction. A tab at the bottom prevents the latitude plates from rotating with the rete. The catalogue lists four plates with latitudes ranging from 22° to 38°. Those are this instrument’s listed plate latitudes, not a universal operating range for all Persian astrolabes.
• The back carries altitude, trigonometric, zodiacal and other scales, including a shadow square. Their engraved geometry allows calculations using a sighting or a selected angle; the instrument is not a continuously running watch. The front and back views are retained together because an exterior portrait alone cannot demonstrate the sighting assembly or catalogue signature.
• The historical catalogue lists a declination scale on the limb and thirteen scales on the back. Its summary also states that the rete contains zero stars, while the separately photographed rete has elaborate pierced forms and a labelled zodiac. Retain that as the catalogue’s recorded count, not a new assertion that every apparent projection has no astronomical function. A closer component study is needed to reconcile the count and visual details; the forty-seven-star count of Oxford 45747 must not be transferred to this accession.
• The catalogue explicitly states that the rule is not original and that the double-ended alidade does not appear original, noting a different sheen and construction. Keep that reservation attached to this accession. A replacement sighting component does not negate the whole instrument’s historical value, but it prevents describing every visible part as original.
• Lewis Evans presented the instrument in 1924 according to the catalogue. Oxford explains that this systematic online catalogue was completed in 2005 and that its general collection database may contain subsequent updates. The historical record establishes holdings, not current display or an independent conservation assessment.

Sources & references

1. https://www.mhs.ox.ac.uk/astrolabe/catalogue/browseReport/Astrolabe_ID%3D168.html
2. https://www.mhs.ox.ac.uk/astrolabe/

Where sources disagree, the disagreement is stated rather than resolved silently.