NMS-F7F720: Medieval Nocturnal

Rights Holder: Norfolk County Council
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Unique ID: NMS-F7F720

Object type certainty: Certain
Workflow status: Awaiting validation Find awaiting validation

Incomplete medieval copper alloy pocket nocturnal: "an astronomical instrument for telling the time at night" (MDA Archaeological Objects Thesaurus 1997, 101). The nocturnal doubles as the lid of a type of cylindrical compendium which also contained a magnetic compass and an equinoctial sundial. Almost complete examples are held by the Oxford Museum of the History of Science (inv. nos. 50896 and 46855) and the British Museum (acc. no. 1853.06181)

A disc with a central perforation and a lateral lug with a hinge set at right angles to the underside, consisting of two incomplete hinge pivots. Opposite the hinge a cut-out into which a catch on the cylinder would have fitted. The cut-out would have engaged with the missing pointer, pivoted on a central rivet. The pointer would be 'P' shaped and slightly overlap the disc, so that it could be aligned to the guide stars around Polaris. One part of the disc's edge is missing.

The central part of the front face is left plain and the outer part is subdivided by twelve short radial lines. In each of the twelve spaces between these lines is a group of five shorter radial lines along with an initial of a month of the year engraved in very irregular and angular script and arranged anti-clockwise. The result is a ring of seventy-two sub-divisions. The centre of the hinged lug is coincident with the line between O[ctober] and N[ovember].

The scale for the months is divided into 5-day intervals (all months have 30 days!) and it also doubles up as the time scale, with two hours per month. Each hour is thus divided to 20 minutes (called a 'mileway' by Chaucer).

Diameter 31.9mm. Thickness of disc 0.8mm. c.1430 - c.1500.

Records of six other nocturnals may be found on the PAS database, from Hampshire (two examples, HAMP1713 and HAMP-831705), Lincolnshire (NLM-ADA657), Norfolk (NMS-C00005), North Yorkshire (LVPL-25A4C7) and Suffolk (SF-5EA704).

Compass bases on this database comprise HAMP-A9E6F1 (now in Gillingham Museum, Dorset), WILT-627124 and one of rather different design to the rest, NMS-82C940. A compass box, found in Suffolk a long time ago, is in the Oxford Museum of the History of Science (inv. no. 34224). A similar compass base is in Norwich Castle Museum (acc. no. 1980.317.634). One example of the sundial part was excavated at Grafendorf Castle near Vienna. A complete (including glass and compass needle) compendium, of a slightly different design from c.1520, is in the Landesmuseum W├╝rttemberg, Stuttgart.

Many thanks are due to Dr John Davis of the British Sundial Society for his invaluable help in this identification and description.


Subsequent actions

Subsequent action after recording: Returned to finder


Broad period: MEDIEVAL
Period from: MEDIEVAL
Period to: MEDIEVAL
Date from: Circa AD 1430
Date to: Circa AD 1500

Dimensions and weight

Quantity: 1
Thickness: 0.8 mm
Diameter: 31.9 mm

Discovery dates

Date(s) of discovery: Thursday 16th February 2017 - Wednesday 15th March 2017

Personal details

Found by: This information is restricted for your login.
Recorded by: Dr Andrew Rogerson
Identified by: Dr Andrew Rogerson
Secondary identifier: Dr John Davis

Other reference numbers

SMR reference number: 31181
Other reference: AHS032017

Materials and construction

Primary material: Copper alloy
Completeness: Incomplete
Surface Treatment: Incised or engraved or chased

Spatial metadata

Region: Eastern (European Region)
County or Unitary authority: Norfolk (County)
District: Breckland (District)
Parish or ward: Snetterton (Civil Parish)

Spatial coordinates

4 Figure: TL9889
Four figure Latitude: 52.4630323
Four figure longitude: 0.91314501
1:25K map: TL9889
1:10K map: TL98NE
Grid reference source: Centred on field
Unmasked grid reference accurate to a 10 metre square.

References cited

No references cited so far.

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Timeline of associated dates

Audit data

Recording Institution: NMS
Created: 2 years ago
Updated: 2 years ago

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