A newly discovered 11th-century Islamic astrolabe inscribed in Arabic and Hebrew is one of the oldest astrolabes ever discovered and one of only a few known in the world. Over the centuries, this astronomical instrument was adapted, translated, and corrected by Muslim, Jewish, and Christian users in Spain, North Africa, and Italy.
Dr. Federica Gigante from the Department of History at the University of Cambridge discovered these artifacts in a museum in Verona, Italy, and published them in the magazine Nuncius.
Dr. Gigante first came across the newly uploaded astrolabe image on the website of the Miniscalchi-Erizzo Museum Foundation. Intrigued, she asked them about it.
"The museum doesn't know what it is," Dr. Gigante said. "But now, it's the most important piece of their collection."
"When I visited the museum and studied the astrolabe up close, I noticed that the astrolabe was not only covered with beautiful Arabic inscriptions, but also faint Hebrew inscriptions. I could only see them clearly in the light coming from the window. I thought I was dreaming, but I saw more and more. This made me very excited."
"This is more than just an extremely rare object. It is a powerful record of centuries of scientific exchange between Arabs, Jews and Christians," Dr. Gigante said. "The Verona Astrolabe went through many modifications, additions and adjustments as it changed hands. At least three users saw it necessary to add translations and corrections to this object, two in Hebrew and one in a Western language."
The Astrolabe was like the world's first smartphone, a portable computer that could be used for hundreds of purposes. It provides a portable two-dimensional model of the universe that users can hold in their hands to calculate time, distance, map star positions, and even predict the future through constellations.
Dr. Gigante, an expert on Islamic astrolabes and former curator of the Museum of Islamic Scientific Instruments, determined the date and location of the "Verona Astrolabe" by analyzing key scientific, design, construction and calligraphy features. She determined that the object was Andalusian, and that the style of carving and the arrangement of the scales on the back matched it with an instrument made in Andalusia, the Muslim Spanish region, in the eleventh century.
One side of the astrolabe is engraved in Arabic "Latitude of Cordoba, 38°30′", and "Latitude of Toledo, 40°" in Arabic, لعزضطليطلةم. Dr. Gigante believes the astrolabe may have been made in Toledo, which at the time was a thriving center of coexistence and cultural exchange among Muslims, Jews and Christians.
The astrolabe had Muslim prayer lines and names of prayers, and these arrangements ensured that the original users could perform their daily prayers on time.
The astrolabe is engraved with the signature: /صنعةيونس[…]لاسحاق, that is, "for Ishak […]/Yunus". This was engraved some time after the astrolabe was made, probably for a subsequent owner.
The names Isḥāq and Yūnus, known in English as Isaac and Jonah, may be Jewish names written in Arabic script, a detail that suggests the object was circulated among the Arabic-speaking Sephardi Jewish community in Spain.
A second additional plate is inscribed with typical North African latitudes, suggesting that another location of use for the object may have been Morocco or Egypt.
The Hebrew inscriptions on the astrolabe were written by no one person. The additions in one group are deeply and neatly carved, while the translations in the other group are very light and uneven, showing the instability of handwork.
"These Hebrew additions and translations suggest that at some point the object left Spain or North Africa and circulated among the Jewish diaspora communities in Italy, where people did not understand Arabic and spoke Hebrew," Dr. Gigante said.
Uniquely, neatly engraved above the Arabic 35° latitude mark is a Hebrew apostille that reads "34.5" rather than "34½", indicating that the engraver was not an astronomer or astrolabe maker.
Other Hebrew inscriptions are translations of Arabic constellation names, such as Scorpio, Sagittarius, Capricorn, Aquarius, Pisces and Aries.
Dr. Gigante noted that these translations reflected suggestions made in the earliest surviving astrolabe treatise written in Hebrew in 1146 by the Spanish Jewish polymath Abraham Ibn Ezra (1089-1167) in Verona, where the astrolabe was discovered today.
Verona in the 12th century was one of the oldest and most important Jewish communities in Italy. Ibn-Ezra's treatise assumes that the Jewish community of Verona had early knowledge of astrolabes, suggesting that astrolabes must have been popular.
Ibn-Ezra's description has much in common with the "Verona Astrolabe", which was in circulation while Ibn-Ezra was in Verona. He cautioned his readers that the instrument must be checked before use to verify the accuracy of the calculated values.
Dr. Gigante believes that the person who added the Hebrew inscription may have followed such advice.
The corrections on the astrolabe are inscribed not only in Hebrew but also in Western numerals, which is the English we use today.
The astrolabe has lightly scratched Western numeral markings on all sides for translation and correction of latitude values, some even multiple times. Dr. Gigante believes the markings were most likely added in Verona for Latin or Italian speakers.
At one point, someone lightly scratched the numbers "42" and "40" near the inscription "Latitude 41°30′ of Medinacheri".
Dr. Gigante said: "Not only are the two numbers different from the Arabic values, they are also inconsistent with each other. It may be that later users of the instrument thought the original Arabic values were wrong and modified them. However, the correct modern value for the latitude of Medina Cree is 41°15′, which shows that the Arabic values are more accurate than either correction."
Elsewhere in the document, Gigante found similar contradictions and erroneous corrections concerning the latitudes of Cordoba and Toledo.
The astrolabe features a "rete" (a perforated disk representing a map of the sky) and is one of the earliest known astrolabes in Spain. It is worth noting that it is very similar to the "rete" of the only existing Byzantine astrolabe (made in 1062 AD) and the "rete" of the earliest astrolabe in Europe (made in Spain based on the Islamic astrolabe).
By calculating the positions of stars, we can roughly calculate the time when the stars were born. Dr. Gigante explained: "Due to a phenomenon called equinox, in which the Earth's axis of rotation does not rotate in a straight line, but rotates in a 'wobble' manner, like a top that is about to stop spinning, the apparent position of the stars above our heads will continue to change, about 1 degree every 70 years."
By analyzing the positions of the stars on the astrolabe, it can be calculated that the positions of these stars are consistent with the positions of stars in the late 11th century and are consistent with the positions of stars on other astrolabes, such as the one made in 1068 AD.
The astrolabe is believed to have belonged to the Verona nobleman Ludovico Moscardo (1611-1681), and was later passed to the Miniscalchi family through marriage. In 1990, the family established the Miniscalchi-Erizzo Museum Foundation to preserve the collection.
Dr. Gigante said: "This artifact is Islamic, Jewish and European. They are inseparable."
Compiled from:ScitechDaily