William Crabtree was an astronomer

Astronomer

An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...

, mathematician

Mathematician

A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....

, and merchant from Broughton

Broughton, Greater Manchester

Broughton is an inner city area of Salford, in Greater Manchester, England. It lies on the east bank of the River Irwell and A56 road, in the northeastern part of the City of Salford, north-northwest of Manchester city centre and south of Prestwich. Broughton consists of Broughton Park, Higher...

, then a township

Township

The word township is used to refer to different kinds of settlements in different countries. Township is generally associated with an urban area. However there are many exceptions to this rule. In Australia, the United States, and Canada, they may be settlements too small to be considered urban...

 near Manchester

Manchester

Manchester is a city and metropolitan borough in Greater Manchester, England. According to the Office for National Statistics, the 2010 mid-year population estimate for Manchester was 498,800. Manchester lies within one of the UK's largest metropolitan areas, the metropolitan county of Greater...

, which is now part of Salford

City of Salford

The City of Salford is a city and metropolitan borough of Greater Manchester, England. It is named after its largest settlement, Salford, but covers a far larger area which includes the towns of Eccles, Swinton-Pendlebury, Walkden and Irlam which apart from Irlam each have a population of over...

, Greater Manchester

Greater Manchester

Greater Manchester is a metropolitan county in North West England, with a population of 2.6 million. It encompasses one of the largest metropolitan areas in the United Kingdom and comprises ten metropolitan boroughs: Bolton, Bury, Oldham, Rochdale, Stockport, Tameside, Trafford, Wigan, and the...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. He was one of only two people to observe the first recorded transit of Venus

Transit of Venus

A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, becoming visible against the solar disk. During a transit, Venus can be seen from Earth as a small black disk moving across the face of the Sun...

 in 1639.

Life and work

Crabtree was born in the hamlet

Hamlet (place)

A hamlet is usually a rural settlement which is too small to be considered a village, though sometimes the word is used for a different sort of community. Historically, when a hamlet became large enough to justify building a church, it was then classified as a village...

 of "Broughton Spout" which was on the east bank of the River Irwell

River Irwell

The River Irwell is a long river which flows through the Irwell Valley in the counties of Lancashire and Greater Manchester in North West England. The river's source is at Irwell Springs on Deerplay Moor, approximately north of Bacup, in the parish of Cliviger, Lancashire...

, near the area now known as "The Priory" in Broughton and was educated at The Manchester Grammar School. He married into a wealthy family and worked as a merchant in Manchester. However, in his spare time, his great interest was astronomy

Astronomy

Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

. He carefully measured the movements of the planets and undertook precise astronomical calculations. With improved accuracy, he rewrote the existing Rudolphine Tables

Rudolphine Tables

The Rudolphine Tables consist of a star catalogue and planetary tables published by Johannes Kepler in 1627 using data from Tycho Brahe's observations.-Previous tables:...

 of Planetary Positions.



Crabtree corresponded with Jeremiah Horrocks

Jeremiah Horrocks

Jeremiah Horrocks , sometimes given as Jeremiah Horrox , was an English astronomer who was the only person to predict, and one of only two people to observe and record, the transit of Venus of 1639.- Life and work :Horrocks was born in Lower Lodge, in...

 (who sometimes spelt his name in the Latised form as Horrox), another enthusiastic amateur astronomer, from 1636. A group of astronomers from the north of England, which included William Gascoigne

William Gascoigne (scientist)

William Gascoigne was an English astronomer, mathematician and maker of scientific instruments from Middleton near Leeds who invented the micrometer...

, formed around them and were Britain's first followers of the astronomy of Johannes Kepler

Johannes Kepler

Johannes Kepler was a German mathematician, astronomer and astrologer. A key figure in the 17th century scientific revolution, he is best known for his eponymous laws of planetary motion, codified by later astronomers, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican...

. "Nos Keplari" as the group called themselves, were distinguished as being the first people to gain a realistic notion of the solar system's size. Crabtree and Horrocks were the only astronomers to observe, plot, and record the transit of the planet Venus

Venus

Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...

 across the Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

, as predicted by Horrocks, on 24 November 1639 (Julian calendar

Julian calendar

The Julian calendar began in 45 BC as a reform of the Roman calendar by Julius Caesar. It was chosen after consultation with the astronomer Sosigenes of Alexandria and was probably designed to approximate the tropical year .The Julian calendar has a regular year of 365 days divided into 12 months...

, or 4 December in the Gregorian calendar

Gregorian calendar

The Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...

). They also predicted the next occurrence on 8 June 2004. The two correspondents both recorded the event in their own homes and it is not known whether they ever met in person, but Crabtree's calculations were crucial in allowing Horrocks to estimate the size of Venus

Venus

Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...

 and the distance from the Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 to the Sun. Unfortunately Horrocks died early in 1641 the day before he was due to meet Crabtree. Crabtree made his will on 19 July 1644, and was buried within the precincts of the Manchester Collegiate Church on 1 August 1644, close to where he had received his education.

The recording of the transit is now seen by many as the birth of modern astronomy in Britain, and indeed, John Flamsteed later said that the work of Horrocks and his north country colleagues laid much of the foundation upon which his work as Astronomer Royal

Astronomer Royal

Astronomer Royal is a senior post in the Royal Household of the Sovereign of the United Kingdom. There are two officers, the senior being the Astronomer Royal dating from 22 June 1675; the second is the Astronomer Royal for Scotland dating from 1834....

 would stand.

On the 9 June 2004, the day after the next transit occurred as predicted by Horrocks, a commemorative street nameplate in memory of William Crabtree was unveiled at the junction of Lower Broughton Road and Priory Grove which marks the northern boundary of Crabtree Croft. A commemorative plaque was unveiled a few yards away in December 2005, at Ivy Cottage 388-90 Lower Broughton Road, which is thought most likely to have been the home of Crabtree and his family at the time when he was collaborating with Horrocks

Crabtree is also celebrated in Manchester Town Hall

Manchester Town Hall

Manchester Town Hall is a Victorian-era, Neo-gothic municipal building in Manchester, England. The building functions as the ceremonial headquarters of Manchester City Council and houses a number of local government departments....

, where a romanticised depiction of his recording of the transit can be seen in a mural (pictured) entitled Crabtree watching the transit of Venus AD 1639 painted by the artist Ford Madox Brown

Ford Madox Brown

Ford Madox Brown was an English painter of moral and historical subjects, notable for his distinctively graphic and often Hogarthian version of the Pre-Raphaelite style. Arguably, his most notable painting was Work...

 in 1903.

Further reading

• Chapman, Allan, '"William Crabtree 1610–1644: Manchester's First Mathematician"', Allan Chapman. Manchester Statistical Society
  Manchester Statistical Society
  Manchester Statistical Society is a learned society founded 1833 in Manchester, England. It claims to be "the first organisation in Britain to study social problems systematically and to collect statistics for social purposes" and in 1834 to be "the first organisation to carry out a house-to-house...
  
  , 1996. ISBN 0-85336-132-0..

External links

• Chasing Venus, Observing the Transits of Venus Smithsonian Institution Libraries
• Manchester Science and Discovery including William Crabtree biography* William Crabtree, Venus genius
• William Crabtree's Venus Transit Observation
• Horrocks and the Dawn of British Astronomy
• Transits of Venus, History results and Legacy