John Jackson (11 February 1887 – 9 December 1958) was a Scottish

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

. He was awarded The

Gold Medal of the Royal Astronomical Society The Gold Medal of the Royal Astronomical Society is the highest award given by the Royal Astronomical Society (RAS). The RAS Council have "complete freedom as to the grounds on which it is awarded" and it can be awarded for any reason. Past awar ...

for his work on stellar parallaxes and star positions.

Early life and education

Born on 11 February 1887 at Mossvale Street,

Paisley, Renfrewshire Paisley ( ; sco, Paisley, gd, Pàislig ) is a large town situated in the west central Lowlands of Scotland. Located north of the Gleniffer Braes, the town borders the city of Glasgow to the east, and straddles the banks of the White Cart Wate ...

Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...

, John Jackson was educated at

Paisley Grammar School Paisley Grammar School is a secondary school in Paisley, the largest town in Renfrewshire, Scotland. The school was founded in 1576 by royal charter of King James VI and is situated on Glasgow Road. The school is recognised as one of Scotland's ...

, studying a range of subjects including the sciences and French and German, but not Latin or Greek, which were compulsory if he intended to sit the entrance examinations for university. Having excelled at science, in particular chemistry, he decided to try for the entrance exam for

Glasgow University , image = UofG Coat of Arms.png , image_size = 150px , caption = Coat of arms Flag , latin_name = Universitas Glasguensis , motto = la, Via, Veritas, Vita , ...

in spite of not studying the classics. During the summer of 1903 he studied hard to improve his knowledge of Latin, which saw him pass the university entrance exam sufficiently well to be awarded a £25 bursary. Graduating in 1907 with a first class honours Master of Arts degree in mathematics and natural philosophy, he was then awarded a fellowship of £100 a year for further study. The following year he undertook a Batchelor of Science degree, again at Glasgow University, with special distinction in

mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...

natural philosophy Natural philosophy or philosophy of nature (from Latin ''philosophia naturalis'') is the philosophical study of physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior throu ...

astronomy Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...

and

chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...

, winning medals in most of these subjects. Astronomy was studied under the tutelage of Ludwig Becker. Jackson gained a thorough grounding in the fundamental elements of the subject to the extent required for a complete understanding of astronomy. He learned how to use a variety of astronomical instruments, how to correct observations and how to apply mathematical and arithmetical analysis to solve astronomical problems. Becker's enthusiastic teaching methods must have had a profound influence on Jackson as he then chose to pursue a career in astronomy. As there seemed to be no possibility of obtaining an appointment in astronomy at Glasgow, Jackson decided to go to

Cambridge University , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...

, and, after taking the entrance exam, was awarded a major scholarship to study at Trinity College as an ordinary undergraduate in 1909. He already knew as much spherical and dynamic astronomy as was then taught at Cambridge, but was introduced to new subjects including solar physics and astrophysics, whilst also furthering his knowledge of pure and applied mathematics. During his time at Cambridge he was awarded further medals for his work in astronomy.

Greenwich Observatory

In 1914 a vacancy as Chief Assistant arose at the

Royal Observatory Greenwich Royal may refer to: People * Royal (name), a list of people with either the surname or given name * A member of a royal family Places United States * Royal, Arkansas, an unincorporated community * Royal, Illinois, a village * Royal, Iowa, a c ...

and Jackson was selected by the Astronomer Royal, Sir

Frank Watson Dyson Sir Frank Watson Dyson, KBE, FRS, FRSE (8 January 1868 – 25 May 1939) was an English astronomer and the ninth Astronomer Royal who is remembered today largely for introducing time signals ("pips") from Greenwich, England, and for the role ...

. During a Zeppelin raid on London Jackson was in the observatory grounds studying the Moon. Urged to take shelter from the bombs by Dyson, Jackson is reported to have said 'the observatory was built to observe the Moon, and I am going to observe the Moon'. In 1917 Jackson was granted a commission in the

Royal Engineers The Corps of Royal Engineers, usually called the Royal Engineers (RE), and commonly known as the ''Sappers'', is a corps of the British Army. It provides military engineering and other technical support to the British Armed Forces and is heade ...

. He was sent to France to work on

sound ranging In land warfare, artillery sound ranging is a method of determining the coordinates of a hostile battery using data derived from the sound of its guns (or mortar or rockets) firing. The same methods can also be used to direct artillery fire at ...

, but in the spring of 1918, after the German armies breakthrough and advances, he was sent to the

British Fourth Army The Fourth Army was a field army that formed part of the British Expeditionary Force during the First World War. The Fourth Army was formed on 5 February 1916 under the command of General Sir Henry Rawlinson to carry out the main British contribu ...

as a trigonometrical survey officer, plotting artillery trajectories. His experience of observing and his knowledge of spherical astronomy meant he was suitably qualified to carry out this work, even resorting to observations of the Sun to help determine ranges and positions. Jackson returned from France in 1919 and resumed his duties at Greenwich. The first extensive task he undertook was to prepare for publication all of the observations he had made of double stars, working on this with

Herbert Hall Turner Herbert Hall Turner (13 August 1861 – 20 August 1930) was a British astronomer and seismologist. Biography Herbert Hall Turner was educated at the Leeds Modern School, Clifton College, Bristol and Trinity College, Cambridge. In 1884 h ...

, the Savilian Professor of Astronomy at

Oxford University Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the ...

. Jackson also worked on calculating the rotation of the planet

Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...

revising the accepted notion of a 7-hour rotation to 19 hours with a possible error of 20 percent, not too far from the true figure of 15.8 hours.

Cape Observatory

In 1933 a vacancy arose for the position of His Majesty's Astronomer at

Royal Observatory, Cape of Good Hope The Royal Observatory, Cape of Good Hope, is the oldest continuously existing scientific institution in South Africa. Founded by the British Board of Longitude in 1820, it now forms the headquarters building of the South African Astronomical Obs ...

, South Africa. Jackson was appointed to the post. Jackson's first task on arrival at the Cape was to work on the large collection of photographic plates taken by David Gill of the sky above Cape Town, in order to derive the proper motions of these stars. He published these in two volumes, which covered the motions and spectral types of over 41,000 stars. Most of Jackson's time at the Cape was taken up with the determination of

stellar parallax Stellar parallax is the apparent shift of position of any nearby star (or other object) against the background of distant objects, and a basis for determining (through trigonometry) the distance of the object. Created by the different orbital p ...

, a programme that had been started by his predecessor,

Harold Spencer Jones Sir Harold Spencer Jones KBE FRS FRSE PRAS (29 March 1890 – 3 November 1960) was an English astronomer. He became renowned as an authority on positional astronomy and served as the tenth Astronomer Royal for 23 years. Although born " ...

. Jackson worked on this for a number of years, taking as many as 1000 photographic plates of the sky in a year from which to work from. Jackson obtained results for 1600 stars, published in three volumes of the Cape Annals. As a result of his work the knowledge of stellar parallaxes for the southern hemisphere became better known than that of the northern. Throughout his career Jackson took part in four expeditions to observe a

total eclipse An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ce ...

of the Sun. The Greenwich observatory had planned to send an expedition to South Africa to observe the eclipse of 1 October 1940, but the outbreak of the Second World War made it impossible to send observers. Equipment was sent instead and Jackson took charge of an expedition from the Cape Observatory to the observing site, where the total eclipse was successfully viewed.

Awards and legacy

Royal Astronomical Society Gold Medal awarded to John Jackson

Jackson retired from the Cape Observatory in 1950, being replaced by his assistant Dr R. H. Stoy. He returned to England, where he settled with his wife, Mary Beatrice Marshall, in Ewell, Surrey. In 1952 John Jackson was awarded The

for his work on stellar parallaxes and his contributions to the general problems of star positions and proper motions. Further accolades awarded include the Gill Medal of the

Astronomical Society of Southern Africa The Astronomical Society of Southern Africa (ASSA), formed in 1922, is a widespread body consisting of both amateur and professional astronomers. There are eight autonomous centres throughout Southern Africa. History The Cape Astronomical Associ ...

in 1958 and he was made a CBE in 1950. He held the posts of President of the Royal Society of South Africa in 1949 and was President of the

Royal Astronomical Society (Whatever shines should be observed) , predecessor = , successor = , formation = , founder = , extinction = , merger = , merged = , type = NGO ...

from 1953 to 1955. After retiring he did not leave his passion for astronomy behind, making a trip to Stromatad in Sweden to observe the total eclipse of 30 June 1954. Many of Jackson's medals held at

Coats Observatory, Paisley Coats Observatory is Scotland's oldest public observatory. It is currently closed for refurbishment as part of a 4-year long £42m transformation of the observatory and museum buildings. Located in Oakshaw Street West, Paisley, Renfrewshire, the o ...

, having been donated to the observatory by Paisley Grammar School. The crater

Jackson Jackson may refer to: People and fictional characters * Jackson (name), including a list of people and fictional characters with the surname or given name Places Australia * Jackson, Queensland, a town in the Maranoa Region * Jackson North, Qu ...

on the far side of the Moon is named after him. Ill health plagued his later years and on 9 December 1958 John Jackson died after a brief illness.

References

External links

John Jackson page at Epsom and Ewell History website

{{DEFAULTSORT:Jackson, John 1887 births 1958 deaths People from Paisley, Renfrewshire Scottish astronomers Recipients of the Gold Medal of the Royal Astronomical Society Fellows of the Royal Society Presidents of the Royal Astronomical Society