Description
Although Robert Stewart Whipple purchased his first antique instrument in 1913, it was not until the 1920s that his collection really began to grow. This dipleidoscope is one of the first hundred objects that Whipple acquired, and demonstrates the early development of his taste for historic scientific artefacts and books.

The dipleidoscope is an instrument for determining true noon to an accuracy of within 10 seconds. A prism creates a double image of the Sun, which merge together as the Sun approaches its high point in the sky.
07/10/2025
Created by: Hannah Price on 07/10/2025

Description
This instrument is used to determine true noon to an accuracy of within 10 seconds. A prism creates a double image of the sun, which merge together as the sun approaches its high point in the sky. When the two images overlap, it is local true noon.

The chronometer and clockmaker Edward John Dent patented his design for the dipleidoscope in 1843, and he exhibited the instrument at the Great Exhibition in London in 1851.

Knowing local noon is useful, for example, for checking and correcting clocks. It is also used in the determination of longitude, which can be calculated by finding the difference in time between local noon and midday at the prime meridian in Greenwich. Whilst the former can be found using a dipleidoscope or sextant, the latter must be read from an accurate chronometer set to Greenwich time.
16/07/2015
Created by: Joshua Nall on 16/07/2015