Thread by @tamar_marvin

Want to hear a story abt Jewish astrolabes?

An #astrolabe is an astronomical instrument for various calculations, superseded by clocks, calculators, computers

But the astrolabe built the world as we know it & Jews played a key role in transferring this knowledge across cultures

The 14thcen Iberian astrolabe pictured above, w/ Hebrew lettering, was chosen by the @BBC for its History of the World in 100 Objects

You can see much more detailed info & images of it here: britishmuseum.org/collection/obj…

There's robust scholarship on these

bbc.co.uk/programmes/b00…

A mashup of Greek technologies, knowledge of the astrolabe wends its way, as with much ancient thought, into Syriac & Arabic then sometimes via Hebrew and/or European vernaculars into Latin.

Astrolabe is a Grk word transliterated in Arabic, Persian & Hebrew, at times translated

You should absolutely watch this adorable video (yes the history of science can be adorable) about the basics of using an astrolabe.

Slight quibble, I wouldn't say astronomy was the handmaid of astrology, but yeah, astrology was a big deal.

Also, you can now make your own astrolabe with office supplies.

This one is more DIY style: uaf.edu/museum/educati…

This one is fancy: joh.cam.ac.uk/way-stars-buil…

Told you #histsci is adorable (and amazing).

Avraham bar Hiyya (d c 1136), a mathematician & philosopher in Barcelona may have translated a treatise on the astrolabe. Avraham Ibn Ezra (*the* Ibn Ezra) wrote one, Kli ha‐Nehoshet. It's posited that in 2nd quar 12th cen there was a burst of translation on astrolabes via Hebrew

Guess who loved on the astrolabes later in the middle ages? Provençal Jews, natch. Rabbis there were into philosophy, allegory, science, medicine, all the rationalist stuff from Sefarad. Here's a commentary in unmistakable Provençal hand on Kli ha-Nehoshet - Bet Din London MS 138

Yaavov b. Makhir Ibn Tibbon (c. 1236-1306) from Marseille, active in Montpellier, defender of philosophy in the Maimonidean controversies, was a prolific translator of scientific works & wrote a treatise on an improvement on the astrolabe he called רובע ישראל "Israel's quadrant."

It was highly sought & there's a large # of surviving manuscripts, as there are for all the astrolabe works. The end describes the construction. The image is copyrighted but you can see a diagram here in BNF MS heb 1027 fol 85v, a beautiful 14-15thcen MS:

web.nli.org.il/sites/NLI/Engl…

Yaakov b. Makhir himself translated Rova Yisrael into Latin w/ Armengaud of Blaise, a fellow traveler in terms of fascinations

Then none other than Ralbag in Milkhamot Hashem, in the overlooked 5th part on astronomy, includes directions for another improvement, the Jacob's Staff

(Arguably; the so-called Jacob's Staff is a different instrument that uses angles to measure distance. The quadrant too is its own thing.)

The cross-staff would become crucial to navigation especially in the 16th cen & a remarkably similar one to Ralbag's was used by Tyco Brahe.

~100 years later, one Yaakov b. Immanuel Provenzale (Bonet de Lattes), who fled expulsion from Carpentras to Rome, made his own mark on the astrolabe.

(We met a Provençal/Provenzale family in an earlier thread but I strongly suspect this is a different family, similarly named.)

So Provenzale invented a ring-astrolabe that could be perched on a finger. The mathematician Charles Bovillus (1470-1553) relates in the introduction to Dialogi de Trinitate that he met Provenzale in the Roman ghetto in 1507 & went to his house in order to see his ring-astrolabe.

Meanwhile, back in Iberia, just before those expulsions, we find Avraham Zacuto, the author of Sefer Yuhasin, avid scientist, and...descendent of Jews fleeing the French expulsions. Zacuto creates an astrolabe that can better be used at sea.

Zacuto has this student.

Zacuto flees Castile-Aragon for Portugal, then gets expelled from there too, making his way to Tunis. But his student hands a translation of Zacuto's astronomical works, including his astrolabe, to Cristobal Colon, better known as Christopher Columbus.

jewishstudies.washington.edu/sephardic-stud…

Sefardi & Provençal Jews were among those who contributed to such world-changing, sciece-advancing technologies (w/ complex legacies). Out of their own hunger to know, they were also cultural intermediaries. Most were also rabbis who made stunning contributions to Torah culture.

To close it out, here's Bilaam using an astrolabe, obviously, for his sorcery, from the Kennicott Bible (MS Kennicott 1, fol 90r). You also *must* click over to see this image of a group of Jews using an astrolabe in the Copenhagen Moreh ha-Nevukhim: www5.kb.dk/permalink/2006…