Accession No
1262
Brief Description
astrolabe with Rojas-type universal projection, attributed to Antoine Mestrel, French, mid-16th Century
Origin
France; Paris [based on attributed maker]
Maker
Mestrel, Antoine [attributed]
Class
astronomy
Earliest Date
1550
Latest Date
1550
Inscription Date
Material
metal (brass)
Dimensions
diameter 203 mm; thickness 4 mm
Special Collection
Provenance
Purchased from a private collection in 09/1953.
Inscription
Description Notes
Astrolabe with Rojas-type universal projection, attributed to Antoine Mestrel, [French], mid 16th century.
Universal astrolabe with rotating calendar plate fixed in mater on reverse.
Mater formed by two joined brass plates, including integral decorated throne. Attached to throne by a shackle-support, decorated with a “Tudor” rose, is a misshapen suspension ring. Inset calendar plate rotates around central rivet, with shaped head on front, but hammered flat on reverse.
Front of astrolabe is engraved with universal projection of the Rojas-type. Degree scale around the circumference is divided 0-90-0-90-0 to single degrees, and marked in fives. 15 stars are labelled: SIGNUS, EXTRE CAU URSAE MAI, HIRCUS, DEX HUM ORIO, CAPUT 3 ANTE CED, CAUDA LEON, COR LEONIS, OCULUS TAUR, CANIS MI, LUCIDA HID, AQUILA, CAUDA CAPRICOR, SPICA VIRGI, CANIS MA, COR SCORPII.
On reverse, circumference of mater is divided into twice-12 hours, labelled in Roman numerals; and into single degrees 90-0-90-0-90 , marked in fives. Rotating plate carries: calendar scales of zodiac houses and months, band of 12 labelled stars for horary quadrant, shadow square. Zodiac scale divided to single degrees, marked in fives, with zodiac house names and astrological signs. Scale of months divided to single degrees, marked at 10, 20, and month ends; labelled with Latin month names: IANUARIUS, FEBRUA, MARTIUS, APRILIS, MAIUS, IUNIUS, IULIUS, AUGUSTUS, SEPTE~BER, OCTOBER, NOVE~BER, DECE~BER. 1st point of Aries is 11th of March. Marked stars: HIRCUS, CANOPUS, CAPUT 3 ANTECE, COR LEONIS, OCULUS 2, DEX HUM ORION, CANIS MINOR, LUCIDA HIDRAE, SPICA VIRGINIS, COR SCORPII, LIBRA, CAUDA CAPRICOR. Horary quadrant marked for equal and unequal hours. Shadow square divided 0-12-0-12-0 and marked in threes.
Lacks alidade and rule. Shackle support for suspension ring is weak. Otherwise, in good condition.
Attributed to Mestrel based on similarities to a 1551 astrolabe signed by Mestrel in the collection of the Museum of the History of Science, Oxford (Inventory Number: 32378).
References
Events
Description
An astrolabe is a model of the heavens with the earth placed at the centre. A section of the heavens is projected onto the astrolabe. The co-ordinates of stars and planets are depicted on a grid called the rete. The earth is represented by latitude plates of which there are more than one. This is because the movement of the stars depends upon the latitude of the place from where the observation is made. Cambridge has a latitude of 52°, Rome 42°, Madrid 41°, and Paris 49°. Each latitude plate has circles and lines engraved on them which include the tropic of Cancer and Capricorn, the equator and a twilight line. The rete and latitude plates are housed within the mather which has a raised edge called the limb. On European astrolabes the limb is engraved with a degree scale showing 0° to 360° and / or a scale of 24 equal hours.
On the back of the astrolabe are engraved several scales including a calendar scale and a shadow square. On Islamic astrolabes extra scales and tables are engraved for finding the direction of Mecca (for times of prayer). At the back of the astrolabe is also the alidade (see diagram above). The alidade has sights through which an astronomer would take simple observations of the sun or of a particular star, to find the time of day or night. The sights can also be used for finding the heights of buildings, trees or hills.
From display label:
An universal astrolabe of the Rojas type without latitude plates.
15 stars are plotted and named. On the reverse is a calendar scale, a shadow square, and an horary quadrant.
FM:39699
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