Instruments · Portable diptych sundial
Portable diptych sundial by Hans Tröschel the Elder, Germany, ca. 1598
- Maker / attribution
- Hans Tröschel the Elder (Maker)
- Date
- ca. 1598
- Historical period
- Renaissance Horology (1400 – 1600)
- Country of origin
- Germany
- Object type
- Portable diptych sundial
- Materials / technique
- Ivory, brass
- Dimensions
- Overall: 3 1/2 × 2 3/8 in. (8.9 × 6 cm)
- Holding institution
- The Metropolitan Museum of Art, New York
- Accession / object no.
- 03.21.38
- Credit line
- Gift of Mrs. Stephen D. Tucker, 1903
- Catalogue title (original)
- Portable diptych sundial
Record summary
Held and catalogued by The Metropolitan Museum of Art, New York (object number 03.21.38), this is a portable diptych sundial by Hans Tröschel the Elder, made in Germany, dated ca. 1598. The Atlas places it in the Renaissance Horology period (1400 – 1600) of its Instruments collection. Materials and techniques recorded by the source: Ivory, brass. Recorded dimensions: Overall: 3 1/2 × 2 3/8 in. (8.9 × 6 cm). The record is illustrated with 4 photographs.
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
Renaissance Horology (1400 – 1600)
Spring power makes clocks portable; Nuremberg and Augsburg produce the first watches; the Prague Orloj is built.
Instrument-making flourished in Nuremberg, Augsburg, Louvain and London: ivory diptych dials, astronomical compendia, astrolabes and nocturnals for wealthy patrons, navigators and scholars.
Read the period in the timelineMore instruments from this periodEarlier: Medieval Period
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.
Read next:The history timeline
Related records
Instruments · 1462
Astrolabe by Regiomontanus, Germany, 1462
The Metropolitan Museum of Art, New York
Instruments · ca. 1500
Sundial, Germany, ca. 1500
The Metropolitan Museum of Art, New York
Instruments · 1501-1600
Circular sundial, copper gilt and engraved, German, 16th century (no compass needle on cover glass)
Science Museum Group, London
Instruments · 1501-1600
Tablet sundial, ivory, 3" x 1 3/4", German, 16th century
Science Museum Group, London
Instruments · 1531
Sundial with compass, in an engraved block of ivory by Gresel, German dated 1531
Science Museum Group, London
Instruments · 1531-1570
Sundial, Germany, 1531-1570
Science Museum Group, London
Instruments · 1537-1632
Tablet Sundial, ivory, engraved and coloured, 4 3/4"x3" (chipped)
Science Museum Group, London
Instruments · 1537-1632
Tablet sundial of ivory, 3 x 1 7/8-inches, by Hans Ducher, Nuremberg, Germany, 1537-1632 (see note).
Science Museum Group, London