Combined Nocturnal and sundial c. 1580
On application
An unusual combined brass nocturnal and sundial of c. 1580. This instrument tells the time by day or night anywhere in the world. One side has a nocturnal, the other the Rojas projection for the form of altitude sundial. On the obverse on the outer rim is stamped ‘Heures du jour Heures de nuit’ and with the numbers 0-12 twice. The second ring is with calendar of the days and calendar of the moon. The pointer is signed dubbe. The term “dubbe” on a Nocturnal likely refers to “Dubhe,” which is one of the stars in the Big Dipper (Ursa Major) constellation. Dubhe, along with Merak (another star in the Big Dipper), forms a line that points directly to Polaris, the North Star. This alignment is useful for navigation and timekeeping at night, as the positions of these stars relative to Polaris can help determine the time. Centrally, a volvelle shows the moon phase through an aperture.
The reverse shows a rojas projection and is stamped on the outer ring with degree scale and ‘Horloge universelle de Jour et de Nuit’. At second ring on the outer side the zodiac symbols and ‘Pole Antartique Signes septentrionaux’, Pole Artique Signes Septentrionaux’ ‘Tropique de Cancer’. On the third ring On the outer third ring an engraved quadrant with on top an alidade which is soldered due a damage.
Length: 9 cm, diameter: 5,8 cm.
