Sundial by E M CRR, Austria, 1701-1750 — view 1 of 2
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Instruments · Analemmatic sundial

Sundial by E M CRR, Austria, 1701-1750

DocumentedDocumented from the holding institution's catalogue record.
Maker / attribution
E M CRR (maker)
Date
1701-1750
Country of origin
Austria
Object type
Analemmatic sundial
Holding institution
Science Museum Group, London
Accession / object no.
1987-1160
Credit line
Wellcome Trust
Catalogue title (original)
Analemmatic sundial, for latitude 47, in stone

View the source record ↗

Record summary

Held and catalogued by Science Museum Group, London (object number 1987-1160), this is an analemmatic sundial by E M CRR, made in Austria, dated 1701-1750. The Atlas places it in the Early Modern Horology period (1600 – 1750) of its Instruments collection. The record is illustrated with 2 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

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

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

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