Charles Piazzi Smyth - Astronomical Career

Astronomical Career

Charles Piazzi Smyth (pronounced /ˈsmaɪθ/) was born in Naples, Italy, to Captain (later Admiral) William Henry Smyth and his wife Annarella. He was called Piazzi after his godfather, the Italian astronomer Giuseppe Piazzi, whose acquaintance his father had made at Palermo when serving in the Mediterranean. His father subsequently settled at Bedford and equipped there an observatory, at which Piazzi Smyth received his first lessons in astronomy. At the age of sixteen he became an assistant to Sir Thomas Maclear at the Cape of Good Hope, where he observed Halley's comet and the Great Comet of 1843, and took an active part in the verification and extension of Nicolas Louis de Lacaille's arc of the meridian.

In 1846 he was appointed Astronomer Royal for Scotland, based at the Calton Hill Observatory in Edinburgh, and professor of astronomy in the University of Edinburgh. Shortly after his appointment, the observatory was placed under the control of Her Majesty's Treasury and suffered from a long series of under-funding. Because of this, most of his notable work in astronomy was done elsewhere. Here he completed the reduction, and continued the series, of the observations made by his predecessor, Thomas James Henderson. In 1853, Smyth was responsible for installing the time ball on top of Nelson's Monument in Edinburgh to give a time signal to the ships at Edinburgh's port of Leith. By 1861, this visual signal was augmented by the One O'Clock Gun at Edinburgh Castle.

In 1704 Isaac Newton wrote in his book Opticks Book 1, Part 1 ' ... ... cannot be so formed as to take away that confusion of the Rays which arises from the Tremors of the Atmosphere. The only Remedy is a most serene and quiet Air, such as may perhaps be found on the tops of the highest Mountains above the grosser Clouds.' This suggestion fell on deaf ears until in 1856, Smyth petitioned the Admiralty for a grant of £500 to take a telescope to the slopes of Teide in Tenerife (which he spelt Teneriffe) and test whether Newton had been right or not. In South Africa he had spent many nights observing from mountain tops but when he moved to Edinburgh had been appalled by the poor observing conditions there.

The Admiralty approved his grant and he was offered the loan of further equipment from many sources. Robert Stephenson loaned his 140 ton yacht 'Titania' for the expedition. Mr. Hugh Pattinson loaned his refracting telescope of 7 inches (18 cm). This was a Thomas Cooke equatorial with setting circles and a driving clock. The Crimean War had recently concluded and the army offered to lend tents. This offer was declined as Piazzi Smyth had already designed a tent with a sewn-in groundsheet based on his experience in South Africa.

On this and all his subsequent trips he was accompanied by his wife whom he had married the previous year. In 1856, on reaching Tenerife they first set up camp on Mount Guajara, a 8,900 ft (2,700 m) peak about 4 miles (6.4 km) south of Teide (all heights on Tenerife are those he derived barometrically). It was higher than all its neighbours and free from any volcanic activity. They took all their equipment up loaded on mules, except for the Pattinson telescope which was much too bulky. They stayed there a month making astronomical, meteorological and geological observations. He made observations of the steadiness and clarity of star images with the 3.6-inch (9 cm) Sheepshanks telescope and found both much better than at Edinburgh. He also made the first positive detection of heat coming from the Moon. Unfortunately they were annoyed by frequent dust incursions which frequently blotted out the horizon. Even when the dust was at its worst, the transparency at the zenith was better than at Edinburgh.

The dust was evidently confined to individual layers, so he decided to move to Alta Vista at 10,700 ft (3,300 m), on the eastern slope of Teide, the highest point that mules could reach. He was determined to use the larger Pattinson telescope and returned to Orotava to fetch it. As the three boxes were too heavy, they were opened and the contents distributed among several smaller boxes which were loaded on to seven strong horses. The telescope was soon mounted and in action. The Airy Disc was clearly seen and he made many critical observations and fine drawings. They spent a month there during which they spent a day climbing to the summit of Teide at 12,200 ft (3,700 m).

The scientific results were described in reports addressed to the Lord Commissioners of the Admiralty, the Royal Society, and the 'Astronomical Observations made at the Royal Observatory, Edinburgh Vol XII 1863' which were widely acclaimed. Piazzi Smyth was the pioneer of the modern practice of placing telescopes at high altitudes to enjoy the best observing conditions.

He wrote a popular account of the voyage in 'Teneriffe, an astronomers Experiment'. This was the first book ever illustrated by stereoscopic photographs ('photo-stereographs'). It included 20 stereoviews of Teneriffe taken by the author using the wet collodion process. A stereoscope could be purchased which allowed the pictures to be viewed in 3-D without removing them from the book.

In 1871 and 1872 Smyth investigated the spectra of the aurora, and zodiacal light. He recommended the use of the rain-band for weather forecasting and discovered, in conjunction with Alexander Stewart Herschel, the harmonic relation between the rays emitted by carbon monoxide. In 1877-1878 he constructed at Lisbon a map of the solar spectrum for which he received the Makdougall Brisbane Prize in 1880. Smyth carried out further spectroscopic researches at Madeira in 1880 and at Winchester in 1884.

In 1888 Smyth resigned as Astronomer Royal in protest at the chronic under-funding and age of his equipment. This brought events to a head and the Royal Observatory was almost closed when James Linday, Earl of Crawford made a donation of new astronomical instruments and the complete Bibliotheca Lindesiana in order that a new observatory could be founded. Thanks to this donation, the new Royal Observatory on Blackford Hill was opened in 1896. After his resignation, Smyth retired to the neighbourhood of Ripon, where he remained until his death.