Linz, Austria · fl. c. 1580–1600
Johann Christoph Keller
Partially verifiedLinz mathematician and sundial maker
Life & work
Johann Christoph Keller was a mathematician from Linz, known as the maker of several sundials that can be dated to around 1600.
His silver equinoctial dial of about 1580, in the History of Science Museum, Oxford, is signed 'IO CHRISTOF KELLER MATHE LINCI' and calls itself a universal horologium; its hour ring, adjustable by two screws, lets it be used at any latitude. The engraved silver base stands on four bun feet and carries a levelling plummet, a latitude scale and an inset compass with the magnetic deviation marked, decorated with flowers, leaves and two angels. His inclining dial of about 1600, also in Oxford, is a brass plate on gimbals that a sliding counterpoise adjusts for latitudes between 45 and 55 degrees, with a pivoted compass that stays level; the museum considers its wooden case modern.
The printed reference the museum cites is Ernst Zinner's Deutsche und Niederländische astronomische Instrumente des 11. bis 18. Jahrhunderts (2nd ed., Munich, 1967).
The fuller biography summarises the open references listed under Sources; each statement was checked against the cited passage. Confirm key dates in period documents before relying on them.
Timeline
Johann Christoph Keller's recorded dates, dated events from this profile and its sources, and dated pieces and sales from the object catalogue. Dates are as each record gives them.
c. 1580 · Career
First recorded as working
1580 · Career
His silver equinoctial dial of about 1580, in the History of Science Museum, Oxford, is signed 'IO CHRISTOF KELLER MATHE LINCI' and calls itself a universal horologium; its hour ring, adjustable by two screws, lets it be used at any latitude.
1580 · Career
Equinoctial dial, circa 1580, silver, 85 x 62 x 53 mm; History of Science Museum, Oxford, inventory 51108.
circa 1580 · Catalogued piece
1600 · Career
Last recorded as working
1600 · Career
Johann Christoph Keller was a mathematician from Linz, known as the maker of several sundials that can be dated to around 1600.
1600 · Career
His inclining dial of about 1600, also in Oxford, is a brass plate on gimbals that a sliding counterpoise adjusts for latitudes between 45 and 55 degrees, with a pivoted compass that stays level; the museum considers its wooden case modern.
1600 · Career
Inclining dial, circa 1600, brass in a wooden case, 113 x 116 x 67 mm; History of Science Museum, Oxford, inventory 35317.
circa 1600 · Catalogued piece
1967 · Career
Jahrhunderts (2nd ed., Munich, 1967).
Documented works
- Equinoctial dial, circa 1580, silver, 85 x 62 x 53 mm; History of Science Museum, Oxford, inventory 51108.
- Inclining dial, circa 1600, brass in a wooden case, 113 x 116 x 67 mm; History of Science Museum, Oxford, inventory 35317.
Collecting significance
The catalogued pieces listed on this page show the kinds of objects auction houses, dealers and museums attribute to this maker; each attribution is the source's own.
Firms, key models & movements
No firm, model or movement in this encyclopedia is yet recorded under this maker's name.
In the object catalogue
2 catalogued objects are recorded under Johann Christoph Keller. Attributions are as given by each source and are not independent authentication.
- Equinoctial Dial by Johann Christoph KellerRing & equinoctial sundial · circa 1580
- Inclining Dial by Johann Christoph KellerOther sundial · circa 1600
Provenance
Where the 2 catalogued pieces by Johann Christoph Keller were recorded, with the collectors, owners and sales their records name.
Provenance map
Each piece is linked to the museum, auction house or dealer whose record it comes from, and to any other house or collection its own provenance names. Select a name to see its pieces.
Museums · 2 pieces
History of Science Museum, Oxford
Museum · 2 pieces · Directory entry
Equinoctial Dial by Johann Christoph KellerRing & equinoctial sundial · circa 1580 · Record source
The record names no sale, lot or earlier owner.
Inclining Dial by Johann Christoph KellerOther sundial · circa 1600 · Record source
The record names no sale, lot or earlier owner.
Each line is copied from the object's source record and is not independently verified. Holders are as recorded when the piece was catalogued: museum objects may not be on display, and sold lots have since changed hands.
Sources & references
- Johann Christoph Keller (Epact makers), History of Science Museum, Oxford, retrieved 2026-11-04 (paraphrased; text © the publisher)
- Equinoctial Dial signed by Johann Christoph Keller, circa 1580, History of Science Museum, Oxford, retrieved 2026-11-04 (paraphrased; text © the publisher)
- Inclining Dial signed by Johann Christoph Keller, circa 1600, History of Science Museum, Oxford, retrieved 2026-11-04 (paraphrased; text © the publisher)
Where sources disagree, the disagreement is stated rather than resolved silently.