Instruments · Sundial
Sundial by Johann Koch, Sweden, 1675
- Maker / attribution
- Johann Koch (maker)
- Date
- 1675
- Historical period
- Early Modern Horology (1600 – 1750)
- Country of origin
- Sweden
- Place
- Sweden, Stockholm
- Object type
- Sundial
- Materials / technique
- kotelo, metal, brass
- Dimensions
- height: 3 cm; diameter: 8.9 cm
- Holding institution
- Suomen kansallismuseo
- Accession / object no.
- H43041:
- Credit line
- Suomen kansallismuseo (via Finna)
- Catalogue title (original)
- aurinkokello ja kompassi (Finnish)
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Record summary
Held and catalogued by Suomen kansallismuseo (object number H43041:), this is a sundial by Johann Koch, made in Sweden, Stockholm, dated 1675. The Atlas places it in the Early Modern Horology period (1600 – 1750) of its Instruments collection. Materials and techniques recorded by the source: kotelo, metal, brass. Recorded dimensions: height: 3 cm; diameter: 8.9 cm. The record is illustrated with 3 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
Description — Suomen kansallismuseo
fyysinen kuvaus: Pyöreä, lasi-ikkunainen messinkikotelo, jonka sisällä on kompassineula; tämä on kiinnitetty valkoiseen alustaan, johon myös on maalattu kaikkia ilmansuuntia osoittavat säteet ja joka on asteikolla jaettu. Kotelon reunassa on 2 x 12 roomalaisia numeroita sekä kaiverrus: Johann Koch fecit 1675. Keskellä kehystä VI-VI kulkeva akseli, jossa on pystysuuntaan liikkuva neula, mikä varjollaan osoittaa ajan. Litteässä kannessa on keskellä sisäkkäin kolme uurrettua rengasta.
Shown in the original language of the source catalogue. An editor-reviewed English translation has not yet been published; we do not publish machine translations as authoritative text.
Inscriptions & marks
kirjoitus: Johann Koch fecit 1675, ks. lappuluettelo, kellon reunassa
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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