Chronograph - R. Ellery Design, Melbourne Observatory Workshop
Record status
Individual type · partial
Period
1860s-1870s
This drum chronograph is a scientific instrument designed by Robert Lewis John Ellery, the Government Astronomer in Victoria, and built at the Melbourne Observatory workshop.
It dates to the 1860s or 1870s. The device is constructed on a wooden base with a large cylindrical brass drum for recording data. It features an electromagnetic mechanism connected to a recording pen, which produces marks on the drum when activated by an observer using a transit instrument. A centrifugal governor is mounted vertically on a black frame to maintain a constant speed for the rotating drum. This instrument was utilized at the Melbourne Observatory between 1870 and 1880 to record the transits of stars and other heavenly bodies, providing precise timing data for astronomical research.
The configuration includes brass fittings and a prominent governor assembly, reflecting its purpose in observatory observational procedures.
Evidence at a glance
- Linked sources
- 1
- Photograph views
- 1
- Catalogue references
- 0
Counts describe this entry’s documentation, not authenticity, rarity or completeness. Photographs may show one specimen; check each caption and licence.
Technical characteristics
- Date
- 1860s-1870s
- Type
- Drum chronograph
- Maker
- Robert Lewis John Ellery
- Origin
- Melbourne Observatory Workshop
- Dimensions
- 80 cm x 40 cm x 65 cm
- Place recorded
- Australia
- Maker / attribution
- Robert Lewis John Ellery
- Registration number
- ST 38319
Design
- Visible features
- • Large brass recording drum mounted horizontally • Vertical centrifugal governor with a golden spherical weight • Electromagnetic mechanism with two black cylindrical coils • Mounted on a rectangular wooden base with brass support feet
- Operational Function
- This device functioned as a recording tool for astronomical observations. When an astronomer observed a star crossing the transit lines, they pressed a button connected to the chronograph. This action triggered an electrical impulse sent to the electromagnetic coils. The activation of these coils moved a pen positioned over the drum. This motion created a physical mark on the drum surface at the exact moment the observation occurred. By synchronizing this pen movement with the rotation of the drum, observers could document the timing of celestial events with the necessary accuracy for meridian transit work.
- History and Provenance
- It was constructed specifically within the Melbourne Observatory workshop during the mid-to-late nineteenth century, specifically the 1860s or 1870s. The instrument remained in active use at the Melbourne Observatory located in South Yarra for a decade, spanning from 1870 to 1880.
- Design and Construction
- The chronograph is built on a heavy wooden plinth that supports the primary mechanical assemblies. At the center lies a large, horizontally mounted brass drum, which serves as the recording surface. This drum is coupled to a gear train housed within a metal framework, which dictates the rotational speed. The entire system is supported by several brass pillars. A prominent feature of the construction is the speed regulation system. A centrifugal governor with a spherical weight is mounted on a tall, black metal frame. This governor provides the necessary torque and speed consistency required for precise astronomical measurement. Adjacent to the drum is an electromagnetic assembly, consisting of two black-painted coils that respond to electrical impulses sent from a transit instrument.
Identification
- Serial number
- ST 38319
- Source note
- Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.
Catalogue references
No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.
Research required
- Research required: Specific date of manufacture remains defined only as the 1860s or 1870s
- Research required: Exact construction components and internal gear mechanisms are obscured by external casing