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Astronomical anniversaries in the month of August

10th August 1675

The foundation stone for the Royal Greenwich Observatory (RGO) is laid by the first Astronomer Royal, John Flamsteed. The observatory was commissioned in 1675 by King Charles II and completed in 1676. The site, located at Greenwich Castle, was chosen by Sir Christopher Wren because of its proximity to London and its location on high ground overlooking the River Thames. It was to be the workplace of the Astronomer Royal and played a major role in the history of astronomy and navigation, mainly because the Prime Meridian passes through it, giving its name to Greenwich Mean Time.

The scientific work of the observatory was relocated in stages elsewhere in the first half of the 20th century and the RGO Greenwich site is now maintained almost exclusively as a museum, although the Annie Maunder Astrographic Telescope became operational for astronomical research in 2018 making it a working observatory again for the first time in 60 years.

Image left: Photograph Toner Stevenson 2002.

1st August 1786

Caroline Herschel discovers the first of her eight comets. Comet C/1786 P1 (Herschel). However poor sky conditions meant that confirmation of the discovery had to wait until the following night.

She was the younger sister of astronomer William Herschel and made the discovery while her brother was away. Her account of her discovery was the first scientific paper written by a woman to be read to the Royal Society and one of the first written by a woman to be included in the proceedings of a scientific society anywhere in the world.

Caroline Herschel went on to discover another seven comets along with nebula as well as doing extensive work on John Flamsteed’s star catalogue.

The silhouette above is of Caroline Herschel, c. 1768, MS. Gunther 36, fol. 146r from the collection of the Oxford University Museum of the History of Science

30th August 1992

Astronomers David Jewitt and Jane Luu announce, after five years of intense searching, they have discovered the first Kuiper Belt Object (KBO), 1992QB1. They initially dubbed the object “Smiley” however in 2018 it received its official name, 15760 Albion, after the works of English poet William Blake. It measures approximately 108–167 kilometres in diameter. The Kuiper Belt is named after Dutch astronomer Gerard Kuiper, who in 1951 predicted that a belt of icy bodies might lay beyond Neptune. 15760 Albion was the first KBO discovered since Pluto (1930) and Charon (1978). Since its discovery, the number of known KBO’s has increased to thousands, and more than 100,000 KBOs over 100 kilometres in diameter are thought to exist.


31st August 1837 Édouard Jean-Marie Stephan. French astronomer.

He was the director of the Marseille Observatory from 1864 to 1907. Until 1872 he was subordinate to Urbain le Verrier, co-discoverer of Neptune. In the early part of his career he had limited opportunities to do observations because he was preoccupied with improving the observatory, however in 1873, after converting the 80 cm telescope at into an interferometer, Stephan was the first person to attempt to measure the angular diameter of a star using interferometry. He also discovered many new nebulae and galaxies and observed the Transit of Mercury in 1867.

In 1884 the French Academy of Sciences awarded him the Valz Prize (Prix Valz). He became a Chevalier of the Légion d'honneur in 1868 and an Officier of the Légion d'honneur in 1879.

Portrait left, unknown photographer.

14th August 1848 Margaret Lindsay, Lady Huggins. Irish-English astronomer.

Born Margaret Lindsay Murray. Irish-English scientific investigator and astronomer. With her husband, Sir William Huggins, she was a pioneer in the field of spectroscopy and co-wrote the Atlas of Representative Stellar Spectra in 1899.

Despite her successful career in astronomy Margaret received no formal training in this field. From a young age she had a keen interest in astronomy, studied popular astronomy books, and was encouraged by her grandfather who was also a keen amateur astronomer.

During her career Margaret and William began photographic experiments, which were meticulously documented in observatory notebooks. Margaret made great improvements to their observatory equipment and the pair quickly rose to the forefront of spectroscopic astrophotography.

Upon her death renowned English astronomer Richard Proctor referred to her as the "Herschel of the Spectroscope". In her will she bequeathed to the Whitin Observatory at Wellesley College some of her astronomy collection including cherished astronomical artefacts. The photographic portrait above is from the Huggins Collection at Whitin Observatory.

24th August 1950 Marc Aaronson. American astronomer.

Aaronson's work concentrated on the determination of the Hubble constant; the study of carbon rich stars and the distribution of those stars in dwarf spheroidal galaxies. Aaronson was one of the first astronomers to attempt to image dark matter using infrared imaging. He imaged infrared halos of unknown matter around galaxies that could be dark matter.

Aaronson died in an accident on 30th April 1987, while observing at the Kitt Peak National Observatory in Arizona, USA, when the hatch leading out to the catwalk was slammed shut on him. The Memorial Lectureship, promoting and recognizing excellence in astronomical research, is held every 18 months by the University of Arizona and Steward Observatory as a tribute to his memory. Asteroid 3277 Aaronson is named in his honour.

Photograph left by Kevin Jarrett, creative commons.

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