Jun 222019

Chambers St, Edinburgh, EH1 1JF

The large black and yellow Schmidt camerascope on display at the National Museum of Scotland

Royal Observatory Edinburgh’s 16/24-inch (0.4/0.6 m) Schmidt camerascope on display at National Museum of Scotland (© National Museum of Scotland)

The Astronomy Technology collections of the National Museum of Scotland contain a variety of artefacts, from orreys (mechanical solar system simulators) to a refracting imaging telescope. One of the larger artefacts on display is the Submillimetre Common-User Bolometer Array, or SCUBA, an instrument to take images of radio-frequency light emitted from dust in nearby galaxies. This red cylindrical device was installed at the James Clark Maxwell Telescope (JCMT) on Mauna Kea in Hawaii between 1997-2005 and produced some of the most impactful astronomy results at the time, surpassed only by the Hubble Space Telescope. This including significantly imporving the understanding of how galaxies are evolving and how new starts are being formed. One of the key partners in the consortium developing SCUBA, and its successor SCUBA-2, was the UK Astronomy Technology Centre, which is based at the Royal Observatory Edinburgh on Blackford Hill.

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Image of SCUBA mounted at JCMT at Mauna Kea

SCUBA mounted at JCMT at Mauna Kea (© Royal Observatory Edinburgh)

Jun 222019

Castlehill, Edinburgh, EH1 2NG

The One O'Clock Gun positioned in the Half Moon Battery within the walls of Edinburgh Castle

One O’Clock Gun (© Roger Cornfoot via Wikimedia Commons)

Because of the poor Scottish weather, the notorious haar (sea fog), and smog, the time ball at the top of Nelson Monument on Calton Hill was rarely visible to the ship navigators in the ports along Leith and Newhaven who needed to accurately adjust their clocks. As such, in 1861, an 18-pound muzzle-loading cannon from the Half Moon Battery at Edinburgh Castle was commissioned into “Time Gun” service. Its present-day successor is still fired every day at precisely 1 o’clock, except for Sundays, Good Friday and Christmas Day. However, as the speed of sound is 343 metres per second (770 mph) and docks were about 2 miles (3km) away, the navigators had to account for about 10.5s delay when they set their clocks. This can be seen on the “Edinburgh Time Map” prepared by the 1 o’clock gun’s proposer, Charles Piazzi Smyth. Interestingly, the gun has also seen an instance of military action, as it was fired on 2 April 1916 at a German Zeppelin conducting an air raid during WWI.

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Black and white illustration of the Half Moon Battery within Edinburgh Castle

Half Moon Battery and firing mechanism in 1861 (Wikimedia Commons)

The time signal delay map designed by Piazzi Smyth

Time signal delay map designed by Piazzi Smyth (© Alastair Bruce)

Photograph of Edinburgh Castle showing the smoke after the One O'Clock Gun was fired

Smoke from the One O’Clock Gun (© Kim Traynor via Wikimedia Commons)

Jun 222019

32 Calton Hill, Edinburgh, EH7 5AA

The Time Ball at the top of the Nelson Monument

Time Ball on Nelson Monument (© Kim Traynor via Wikimedia Commons)

In 1853, the second Astronomer Royal for Scotland, Charles Piazzi Smyth, secured the installation of a time ball at the top of Nelson Monument. This tower, which looks like an “upturned telescope” and is clearly visible from most of Edinburgh, was designed by the architect Robert Burn and erected in 1815. While an interesting curiosity these days, the time ball used to be vitally important to ships in the port of Leith in adjusting their clocks for navigation, as it was  raised and dropped exactly at 1 o’clock each day, a tradition that continues. The ball, constructed of wood, covered in zinc, and weighing 90 kilograms, as well as the operating mechanism were made by Maudslay, Sons and Field of Lambeth, who also made the time ball mechanism for the Greenwich Observatory. It was installed by James Ritchie and Son (Clockmakers) Ltd, who still maintain it to this day on behalf of Edinburgh’s City Council. (There is an untrue myth that the original ball was much heavier, at 762 kilograms, in part perpetuated by Smyth himself!)

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Nelson Monument – Museums and Galleries Edinburgh

Photograph of the National Monument, Nelson Monument, and City Observatory on Calton Hill in the background

National Monument, Nelson Monument (tall tower) and City Observatory from the North (Wikimedia Commons)

Jun 222019

1 Hillside Crescent, Edinburgh, EH7 5DY; marked with a blue plaque

Photograph of 1 Hillside Crescent with the blue plaque commemorating Thomas Henderson above the door to the right

1 Hillside Crescent (with a blue plaque)

Thomas Henderson (1798-1844) became the first Astronomer Royal for Scotland in 1834. He was also appointed Regius Professor of Astronomy at the University of Edinburgh and worked at the nearby Calton Hill Observatory until his death. His scientific achievements include the calculation of the parallax of a fixed star (the angle describing the difference in the position of a star on the night sky as measured six months apart), leading him to be the first person to measure the distance to Alpha Centauri, one of a group of nearest stars to the Sun. Unfortunately, delaying the publication of his results led to German astronomer Friedrich Bessel and Russian astronomer Friedrich Struve receiving credit for first measuring stellar parallaxes. Throughout his time in Edinburgh, he lived at 1 Hillside Crescent and is buried in Greyfriars Kirkyard (very near the memorial in stop number 13 on this tour).

Black and white photograph of Thomas Henderson

Thomas Henderson

Photograph of Thomas Henderson's memorial and grave at Greyfrairs Kirkyard

Thomas Henderson’s memorial/graveside at Greyfriars Kirkyard

Photo credit: Wikimedia Commons

Jun 222019

Colin MacLaurin Road, Edinburgh, EH9 3DW

Black and white photograph of Mary Brück looking through a telescope

Mary Brück

This building at the University of Edinburgh Kings Buildings science campus honours the astronomer and historian of science Mary Brück (1925-2008), who graduated with a PhD from the University of Edinburgh in 1950. She returned in 1962 with the appointment of her husband, Hermann Brück, to the post of the Astronomer Royal for Scotland at the Royal Observatory Edinburgh. She carried out research into stars, the gas and dust between stars and the Magellanic Clouds, while also doing historical research on women in astronomy and the history of astronomy in Scotland and her native Ireland. She published articles in several different journals and collaborated with her husband on a biography of the 19th-century Astronomer Royal for Scotland, Charles Piazzi Smyth. In 2018, the Mary Brück building was opened on Colin MacLaurin Road, itself dedicated to an 18th century champion of Astronomy in Edinburgh (whose memorial is visited as stop number 13 of this tour).

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Mary Brück Building and Brucks’ Cafe

Mary Brück Building and Brucks’ Cafe

Images credit: The University of Edinburgh / Royal Observatory Edinburgh

Jun 212019
Photograph of 53 Northumberland Street

53 Northumberland Street (© Stephen C Dickson via Wikimedia Commons)

53 Northumberland Street, Edinburgh, EH3 6JQ; marked with a blue plaque

Mary Sommerville (1780-1872) is often described as the “queen of science in the 19th Century.” A writer and polymath, she wrote the ground-breaking interdisciplinary book On the Connexion of the Physical Sciences (1834), combining the latest scientific advances in astronomy, physics, chemistry, botany, and geology. Though she wrote extensively on a variety of subjects and was the first person referenced as a “scientist” (in a review of her work in 1834), it is her contribution to Astronomy that is particularly notable: Mary Sommerville was one of the first people to propose the existence of planet Neptune. She was also one of the first two women to be elected members of the Royal Astronomical Society (1835) and co-signatory of John Stuart Mill’s 1866 petition to Parliament to give women the right to vote. Born in Jedburgh in the Borders and growing up in Burntisland, Fife, Mary Somerville lived at 53 Northumberland Street between 1813-16.

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Portrait of Mary Sommerville by Thomas Philips

Portrait of Mary Sommerville by Thomas Philips (Wikimedia Commons)

Cover page of The Connexion of the Physical Sciences

Cover page of The Connexion (1834)