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Acquisition of Edinburgh's Transit Telescope

Edinburgh's Transit Telescope

Edinburgh's Transit Telescope

Edinburgh's Observatory on Calton Hill was completed in 1820 and designated as a "Royal Observatory" by King George IV in 1822. However, at that time, there were no instruments available for astronomical purposes.

Initially it was expected that Edward Troughton, of London, would provide both a Mural Circle and an Altazimuth Circle for the new Observatory, but time passed and Troughton had not been able to make and deliver these instruments.

In early 1825, therefore, a new search for a suitable instrument was made on the continent. At this time Joseph von Fraunhofer was the eminent glass manufacturer and the creator of world class refractor lenses. Fraunhofer was engaged to build a Transit Telescope incorporating a 6.4 inch objective lens. Fraunhofer made the lens, but died in 1826 from the effects of poisoning by the fumes of his glass making activities. He was only 39 years old, and many of his secrets went to the grave with him.

Completion of the Transit Telescope then fell to the Repsold company, run by Johann Georg Repsold. However, he was the Fire Master in Hamburg in addition to running his businesses, and he died in 1830 whilst attending a fire in the city.

One of Johann's sons, Adolf, became his father's successor of his instruments company. It was Adolf who completed the Transit Telescope and delivered it to Edinburgh in November 1831. Much later Adolf was joined by his brother, Georg, and the Repsold company was re-named as "A & G Repsold".

Troughton eventually delivered the Mural Circle and it was installed in 1834.

When Thomas Henderson arrived at the Observatory in 1834 as Scotland's first Astronomer Royal, the observatory was equipped with three high quality measuring instruments, viz the Fraunhofer - Repsold Transit Telescope and the Troughton Mural and Altazimuth Circles.

All were mounted on exactly the same parallel of Latitude. The Transit Telescope was at the eastern end of the main ground floor room, the Mural Circle at the western end, and the Altazimuth Circle was in the upstairs dome - where later equatorially mounted telescopes would be used.