Hebrew astrolabes
and scientific practice of יהודים YEHUDIM.

The British Museum’s astrolabe, registration 1893,0616.3, is a small gilt-brass instrument. Silke Ackermann’s Epact catalog describes its star-bearing rotating framework, called the rete:

24 star names are given partially in Hebrew, partially in Arabic in Hebrew script.²

The distinction is linguistic as well as visual. Hebrew letters can carry Arabic words. The catalog also records Hebrew zodiac names and alphanumerical scales, making writing by יהודים YEHUDIM part of the instrument’s working information.³

Its inner scales record a 28-year solar cycle, weekdays and a leap-year marker. Roman-calendar month names appear in transliteration. Five double-sided plates provide settings for different latitudes.⁴

These markings are a material witness to scientific practice through Hebrew script. They do not identify every person who made, owned or used the instrument. A plate’s latitude describes a setting for calculations; it does not by itself establish an owner’s city.

The instrument is unsigned and undated. Epact tentatively places it in mid-fourteenth-century Spain, using style and month names. The British Museum’s own collection record permits Spain or Italy in that century.⁵⁶

David A. King’s Appendix C in a 2011 study with Mohamed Abuzayed and Petra G. Schmidl argues for Spanish origin for three related Hebrew-inscribed instruments. His note explains why he had earlier entertained Italy and why month names and linguistic evidence changed that assessment. The appendix also states a limit:

No comparative study of the three pieces has been conducted yet.⁷

This is an attributed scholarly reconstruction, rather than a date engraved on the instrument. The three objects remain distinct: the British Museum example, a Paris collection example and Adler Planetarium M-20 in Chicago. Evidence about a later marking on one cannot automatically become the history of another.⁸

The scholarly inventory distinguishes Hebrew working inscriptions, a replacement rete with Hebrew star names, additional geographical labels and a Hebrew owner’s mark. Those forms preserve different kinds of participation. An owner’s signature alone does not establish that the owner built the instrument.⁹

These instruments belong within the intellectual history of יהודים YEHUDIM: their inscriptions and construction preserve evidence of how יהודים YEHUDIM engaged with astronomical knowledge. The strongest account follows the particular inscription and object, keeping makers, users, later additions and modern interpretation separate.

• How does Arabic written in Hebrew letters change what the label “Hebrew astrolabe” can mean?
• Which evidence would distinguish an instrument’s maker from a later owner who added a Hebrew mark?
• Why must a latitude plate and a scholarly attribution remain distinct from a recorded place of manufacture?