Heliometer made for Dunecht Observatory
AssociatedAssociated with
Sir David Gill
(Aberdeen, Scotland, 1843 - 1914)
MakerMade by
A. Repsold and Son
(Hamburg, Germany, 1799 - 1919)
Date1872
Object NameHeliometer
Mediumsteel, glass and mercuryMaster
ClassificationsScience And Technology
DimensionsOverall (Height x Width x Depth): 46 × 30 × 170cm
AcquisitionPresented in 2014 by the Royal Observatory, Edinburgh.
LocationOn Display - Provost Skene's House
Object numberABDMS092798
About MeThis instrument was purchased by Lord Lindsay for the Dunecht Observatory, borrowed by David Gill for his Ascension Island expedition, then purchased by Gill and taken to South Africa. The heliometer is a complex optical instrument used to measure distances between celestial bodies (such as stars) in the sky. Gill’s biographer joked that after his wife, Gill loved his heliometer. Its distinguishing feature is that its large lens is divided in two and mounted so that one part can slide past the other. If the observer moves half the lens using the control knob so that the image of two objects are superimposed, then the angle between the two objects can be found very accurately.
In Gill’s hands, the heliometer became the most precise instrument employed by astronomers in the 1800s. He used it for precision stellar mapping, to find the most accurate value for the size of the solar system (effectively how far the Sun is from the Earth), to find the distance away of nearby stars and, indirectly, to find a value for the mass of the Moon.
Exhibitions
Robert Gordon University
