The Great Equatorial

This image of the Great Equatorial Telescope at the Royal Observatory, Greenwich, is from the Illustrated London News for 24 August 1861. The telescope was installed under the 7th Astronomer Royal, George Biddell Airy, in 1859 as the first of the large equatorially-mounted telescopes at Greenwich. It was a refractor with an aperture of 12.8 inches and an object glass made by Merz of Munich. The optical work was by Troughton & Simms. The enormous mounting was designed by Airy himself and made by Ransomes and Sims of Ipswich. It was mounted in a new, specially designed building, know as the Great Equatorial Building or the South East Dome, until 1891. At this date it was moved to make way for the new and more powerful 28-inch telescope, which reused the same mount. The Great Equatorial was subsequently mounted in the Lassell Dome for a few years before being attached to the Thompson 26-inch telescope as a guiding instrument and mounted with it in the dome of the New Physical Observatory. These telescopes were moved in the 1950s to the new home of the Royal Greenwich Observatory in Herstmonceux in Sussex. The telescope formerly known as the Great Equatorial can, therefore, still be seen at the Observatory Science Centre.

Rebekah Higgitt