Instruments · Portable equatorial sundial

Portable equatorial sundial by Ludewig, ca. 1725

DocumentedDocumented from the holding institution's catalogue record.

Maker / attribution: Ludewig (Maker)
Date: ca. 1725
Historical period: Early Modern Horology (1600 – 1750)
Country of origin: Unrecorded in source
Object type: Portable equatorial sundial
Materials / technique: Brass, water-gilded and silvered; silver
Dimensions: Overall: 2 3/4 × 5 1/8 × 5 1/8 in. (7 × 13 × 13 cm)
Holding institution: The Metropolitan Museum of Art, New York
Accession / object no.: 03.21.22
Credit line: Gift of Mrs. Stephen D. Tucker, 1903
Catalogue title (original): Portable equatorial sundial

Record summary

Held and catalogued by The Metropolitan Museum of Art, New York (object number 03.21.22), this is a portable equatorial sundial by Ludewig, dated ca. 1725. The Atlas places it in the Early Modern Horology period (1600 – 1750) of its Instruments collection. Materials and techniques recorded by the source: Brass, water-gilded and silvered; silver. Recorded dimensions: Overall: 2 3/4 × 5 1/8 × 5 1/8 in. (7 × 13 × 13 cm). 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

The source record does not include a narrative description. The structured fields above are reproduced from it.

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 timeline More instruments from this period Earlier: Renaissance Horology

Atlas type guide

Sundials and solar time-finders

A sundial tells time from the position of a shadow cast by a gnomon or style. Because the sun's apparent motion depends on latitude, every fixed dial is laid out for a particular latitude, and portable dials either carry a latitude scale or are made for one region. Sundials show local apparent solar time, which drifts against mean (clock) time by up to about sixteen minutes over the year — the equation of time.

Portable dials were the pocket instruments of the sixteenth to eighteenth centuries. Nuremberg and Augsburg workshops produced folding ivory diptych dials with inset compasses; English and French makers sold brass horizontal dials, ring dials and the Butterfield type; Japanese and Chinese makers had their own traditions of compass dials. After mechanical watches became reliable, dials remained in use for setting them, and nineteenth-century heliochronometers were built to correct directly for the equation of time.

What to look for

The latitude engraved on the dial plate or a latitude arc on the gnomon — it shows where the dial was meant to be used.
The type of hour lines: equal (equinoctial) hours, Italian or Babylonian hours counted from sunset or sunrise, or unequal temporal hours on early and Islamic instruments.
An inset magnetic compass and whether a magnetic-declination mark is drawn on its card — a useful dating clue because declination changes over time.
Maker's signatures and town marks: Nuremberg compass-makers (Kompassmacher) often struck a personal mark and the town's punch.
Additional scales such as lunar volvelles, wind roses, perpetual calendars or lists of cities with their latitudes.

Dating clues

Ivory diptych dials are characteristic of Nuremberg between about 1500 and 1700.
Butterfield-type dials with a bird-shaped adjustable gnomon point to Paris workshops from the late seventeenth century onward.
Equation-of-time tables engraved on the plate became common after the mid-seventeenth century, once pendulum clocks made the difference between solar and mean time obvious.

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.

Mechanisms mentioned

No escapement or complication is named in the source record. See the encyclopedia for how such pieces work.

Record completeness

Maker or attributionRecorded
DateRecorded
Place or countryNot in source
MaterialsRecorded
DimensionsRecorded
Narrative descriptionNot in source
Inscriptions / marksNot in source
ProvenanceNot in source
Several photographsNot in source

Editorial status: Documented — facts as published by the source; not independently verified by Atlas editors.

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Sources & image rights

Record source: The Metropolitan Museum of Art, New York.

Image rights: CC0 1.0 (Met Open Access).

Images are hosted by the Atlas for study and credited to their owner. Rights holders may request correction, credit changes or removal via the editorial office.

Cite this record

"Portable equatorial sundial by Ludewig, ca. 1725." The Metropolitan Museum of Art, New York, 03.21.22. Catalogue record in The Horology Atlas, WatchMuseum.org, https://atlas.watchmuseum.org/museum/portable-equatorial-sundial-by-ludewig-ca-1725-cad262.