{
  "author": "ChronologiaOS editorial guides",
  "date": "2026-10-09",
  "department": "Technology & Instruments",
  "department_id": "TECHNOLOGY",
  "epistemic_label": "Source guide",
  "epistemic_status": "SOURCE_GUIDE",
  "period": "1235\u20131291 CE",
  "place": "Jazira and Yemen",
  "public_sources": [
    {
      "publisher": "British Museum",
      "title": "Astrolabe 1855,0709.1",
      "type": "Museum object record",
      "url": "https://www.britishmuseum.org/collection/object/W_1855-0709-1"
    },
    {
      "publisher": "Metropolitan Museum of Art",
      "title": "Astrolabe of Umar ibn Yusuf ibn Umar ibn Ali ibn Rasul al-Muzaffari",
      "type": "Museum object record",
      "url": "https://www.metmuseum.org/art/collection/search/444408"
    }
  ],
  "publication_state": "PUBLIC",
  "read_time": "4 min read",
  "sections": [
    {
      "body": "The British Museum's record for astrolabe 1855,0709.1, made by Abd al-Karim al-Misri, gives a date of 1235 to 1236 CE in its current catalogue text. The curatorial note sketches the instrument's Greek invention and its transmission through Hellenistic and Byzantine texts translated into Arabic, with the earliest Islamic astrolabes and treatises in the ninth century.",
      "heading": "Start in London",
      "source": 0
    },
    {
      "body": "The Metropolitan Museum's record for the Rasulid astrolabe of Umar ibn Yusuf dates it to 690 AH, 1291 CE, in Yemen. The museum notes that the object is unusually well documented and connected to an autograph treatise on astrolabe construction in Cairo, a rare link between an instrument and a text about making it.",
      "heading": "Then New York",
      "source": 1
    },
    {
      "body": "The research record uses the London astrolabe as material evidence for Islamic astrolabe practice, but flags that the Greek-to-Arabic transmission summarized in a curatorial note is a historical relationship needing source-chain evidence beyond one summary. It also notes that legacy catalogue pages have shown differing date renderings, which it preserves rather than hides.",
      "heading": "Object evidence and transmission claims"
    },
    {
      "body": "Which is the stronger piece of evidence, a dated inscription on an instrument or a treatise describing how it was made? What does each one leave out?",
      "heading": "A question to carry forward"
    }
  ],
  "short_title": "What can a dated instrument prove?",
  "slug": "two-astrolabes-reading-an-instrument-through-its-record",
  "summary": "Compare two thirteenth-century astrolabes, one in London and one in New York, and see how a museum record, a dated inscription, and a surviving treatise support different kinds of claims.",
  "tags": [
    "Astrolabe",
    "Islamic science",
    "Instruments",
    "Museum records"
  ],
  "title": "Two astrolabes: reading an instrument through its museum record."
}