1911. The works opens
A grinding shop on Scheepmakershaven, four benches, marine optics for the harbour trade.
1911 to 2026
The works stands where it opened in 1911: a grinding shop on Scheepmakershaven, four benches, marine optics for the harbour trade. It has been extended three times since and relocated none. The harbour still runs past the south wall.
Every flat and sphere leaving the optics floor is still hand-figured against a reference, the practice unchanged since 1931. Computer-controlled polishing was trialled here in 1994. The hand-figured reference flats held tolerance longer than the machine did, so the machine left and the benches stayed.
One instrument delivered in 1953 remains under active calibration contract, recertified each March on the bench it was built on. A hundred and fifteen years of production records sit in the archive next door, and the earliest of them, plate CP-0114, still measures true.
The record, 1911 to 2026
1931. Glass over film
The plate camera enters production. The first plate, CP-0114, is still in the archive and still measures true.
1948. Return to production
The works reopens with eleven of the original staff. Hand-figuring is kept deliberately.
1958. Traceability
Admission to the Interlaboratory Calibration Register. Every instrument since ships with a chain to the national standard.
1974. Meridian VIII
A 400 mm interferometer holding λ/40 across the full aperture. It is still the reference instrument in the metrology hall.
1996. Out of the lab
The AM-7 goes to exposed summits. Sealed to seven bar because the weather does not negotiate.
1999. Coherence
The CA-2 walks a delay arm to forty metres and measures what datasheets omit.
2026. One hundred and fifteen years
Six hundred and forty instruments in service. The oldest still under calibration contract was delivered in 1953.
The metrology hall
Six conditions held constant, day and night, so a reading taken in January agrees with one taken in July.
Conditions, current cycle
- Ambient temperature
- 20.0°C ± 0.1, held 24 h
- Vibration isolation
- < 1.0 µm, 1 to 80 Hz, active platform
- Bench
- Granite, 1.8 × 3.6 m, four pneumatic isolators
- Cleanroom class
- ISO 6 (class 1,000)
- Relative humidity
- 45% ± 3
- Illumination
- Sodium safelight, 589 nm; white for inspection only
Six hundred and forty instruments carry this bench's tolerances into observatories, harbours and laboratories.