
Instruments · Nocturnal
Nocturnal, France, 1600–1650
- Maker / attribution
- Unrecorded in source
- Date
- 1600–1650
- Historical period
- Early Modern Horology (1600 – 1750)
- Country of origin
- France
- Place
- France
- Object type
- Nocturnal
- Holding institution
- Rijksmuseum
- Accession / object no.
- NG_NM_12076
- Catalogue title (original)
- Pocket nocturnal and astrolabe of René Descartes (English)
Record summary
Held and catalogued by Rijksmuseum (object number NG_NM_12076), this is a nocturnal, made in France, dated 1600–1650. The Atlas places it in the Early Modern Horology period (1600 – 1750) of its Instruments collection. The record is illustrated with 1 photograph.
Assembled from the source record's structured fields. Dates and attributions are given as the source states them; where a field is missing the Atlas leaves it blank rather than estimating.
Catalogue description
Catalogue description from Rijksmuseum (English)
This instrument was made especially for René Descartes (1596-1650). The Frenchman resided in the Dutch Republic from 1629 to 1650, during which time he conducted experiments and wrote his most important philosophical works. He could use this convenient pocket instrument on his travels. To determine the time at night, the nocturnal (or nocturlabe) had to be aligned with the Pole Star. It also houses a sundial and a compass.
Historical context
Early Modern Horology (1600 – 1750)
Huygens' pendulum and balance spring transform accuracy; English makers develop the anchor and deadbeat escapements.
Pocket sundials, Butterfield dials and sandglasses remained essential companions to imperfect clocks; navigators used sandglasses and the log line; observatories began to combine telescopes with pendulum clocks.
Read the period in the timelineMore instruments from this periodEarlier: Renaissance Horology
Atlas type guide
Nocturnals
A nocturnal tells the time at night from the rotation of the stars around the celestial pole. The user sights Polaris through the central hole and turns a long pointer to align with the 'guard' stars of the Little Bear or the 'pointers' of the Great Bear. A calendar scale set to the date converts that angle to the hour.
Nocturnals were used from the sixteenth to the eighteenth century by navigators and travellers. Many are made of boxwood or brass, with tactile teeth on the hour disc so that the time can be counted in the dark.
What to look for
- A central sighting hole and a long index arm.
- Engraved letters such as 'B' (Bear) or 'BB' indicating which constellation to use.
- Teeth on the hour disc with a longer tooth for midnight.
Dating clues
- Most surviving nocturnals date from about 1550 to 1750.
General guidance written by the Atlas editors about this kind of object. It is not a statement about this particular piece; for that, rely on the source record above and on physical examination.
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