Signed: ANTHOITNE MESTREL APARIS 1551
This instrument was made in Paris in 1551 and is closely related to the book on the astrolabe by Rojas (catalogue no. 43), which was published in Paris in the same year. There is, for example, a strong resemblance between the illustrations of the astrolabe in the book and the instrument itself. One side of the astrolabe has the Rojas universal projection, while the other - the back - has a pivoted alidade with a shadow square and degree scale, a zodiacal calendar and a diagram for converting times between different systems of hours (known as equal and unequal). It is the alidade and shadow square on the back, and possibly the scale of degrees, that were said to have applications to gunnery and military surveying.
Diameter: 257 mm
Inventory no. 32,378