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The Encyclopedia of Horology

Tool · Scientific instrument (equinoctial sundial)

Nicolaus Rugendas Portable Equinoctial Augsburg Dial with Compass

Partially verified

This portable equinoctial Augsburg sundial is signed by Nicolaus Rugendas of Augsburg and dated by the source to circa 1730. Constructed with an octagonal gilt brass plate, it incorporates an inset central compass marked with Latin cardinal points and a revolving magnetic declination disc. The instrument features a crescent-shaped hinged silvered latitude sector calibrated from 20 to 90 degrees, an elevated hour ring, a central rod gnomon, and a folding plummet for leveling. According to the source, the back features a silvered plate engraved with latitudes for 43 world cities, and the instrument rests on three turned gilt brass feet.

Three-quarter perspective view of the portable equinoctial dial showing compass, gnomon, and latitude sector
Three-quarter perspective view of the portable equinoctial dial showing compass, gnomon, and latitude sector — Antiquorum. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
catalog.antiquorum.swiss
Category
Tool · Scientific instrument (equinoctial sundial)
Maker / attribution
Nicolaus Rugendas
Reference
Not recorded
Catalogue / lot identifier
1
Source-reported date
circa 1730
Country
Germany

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Physical Configuration

This portable equinoctial sundial is characterized by an octagonal gilt brass base plate containing a central compass. The instrument includes a spring-loaded gnomon and a folding plummet for leveling purposes.

The base is supported by three turned gilt brass feet. A fitted leather box is mentioned in the catalog record, though this item is not visible in the available documentation.

Evidence for this section
  • “Octagonally shaped, compass in the center”
  • “spring-loaded gnomon, folding plummet for leveling”
  • “three gilt brass turned feet.”
  • “Fine gilt brass and silver portable equinoctial "Augsburg" dial with compass in fitted leather box.”

Dial and Navigation Features

The central compass well features a revolving magnetic declination disc and Latin markings for the cardinal points. A crescent-shaped silvered latitude sector is hinged to the base plate, featuring Arabic calibrations ranging from 20 to 90 degrees.

The underside of the instrument comprises a silvered plate engraved with the latitudes of 43 world cities; this section is not visible in the provided imagery.

Evidence for this section
  • “four cardinal points marked in Latin, revolving magnetic declination disc”
  • “crescent-shaped hinged Arabic latitude sector calibrated from 20 to 90 degrees”
  • “back with silvered plate engraved with latitudes of 43 world cities”

Maker and Attribution

The instrument is signed "Nicolaus Rugendas, Augspurg" above the central compass. The source attributes the dial to Nicolaus Rugendas III (1665–1745) of the Augsburg clockmaking family.

The signature includes the number '48', which the source identifies as the latitude of Augsburg. The date of production is cited as circa 1730.

Evidence for this section
  • “Signed above the compass "Nicolaus Rugendas, Augspurg".”
  • “The "48" in the signature after the maker's name denotes the latitude of Augsburg.”
  • “Nicolaus Rugendas, Augspurg, circa 1730.”

Open research questions

  • Does the current condition of the instrument allow for the physical verification of the 43 recorded city latitudes?
  • What is the physical state of the hinge mechanism for the latitude sector?

Source evidence

Recorded claims and source quotations for Nicolaus Rugendas Portable Equinoctial Augsburg Dial with Compass
FieldSource-reported valueSource quotation
Maker SignatureNicolaus Rugendas, Augspurg“Signed above the compass "Nicolaus Rugendas, Augspurg".”
Dimensions60 x 55 mm“Dim. 60 x 55 mm.”
Latitude Sector20 to 90 degrees“crescent-shaped hinged Arabic latitude sector calibrated from 20 to 90 degrees”
Underside and FeetPlate engraved with latitudes of 43 world cities, three turned feet“back with silvered plate engraved with latitudes of 43 world cities, three gilt brass turned feet.”
Dimensions60 x 55 mm“Dim. 60 x 55 mm.”

Visible details

  • Octagonal gilt brass plate framing a central circular compass well
  • Folding hour ring and central gnomon rod raised above the base
  • Curved silvered latitude sector hinged on the base plate
  • Plummet bracket visible mounted on the opposite edge
  • Engraved inscription beginning 'NICOLAUS' visible on the base plate

Research qualifications

  • The underside plate with city latitudes is not visible in the photograph
  • The fitted leather box mentioned in the catalog description is not shown in the image

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Nicolaus Rugendas, Augspurg, circa 1730. Fine gilt brass and silver portable equinoctial "Augsburg" dial with compass in fitted leather box. | The Private Collection of Theodor Beyer | Hotel Baur Au Lac, Zurich, 16th November 2003

Reviewed 2026-10-25 · Record 829b9ae560

Terms in this record

Glossary explanations for terms named in this object’s record.