William Stephen Jacob (1813–1862) was an English immigrant astronomer in India, who acted as the director of the
Madras Observatory
The Madras Observatory was an astronomical observatory which had its origins in a private observatory set up by William Petrie in 1786 and later moved and managed by the British East India Company from 1792 in Madras (now known as Chennai). The ...
from 1848 to 1859. His early claim of 1855 to have detected an exoplanet, in orbit around 70 Ophiuchi, is now thought to have been mistaken.
Life
The seventh child of Stephen Long Jacob (1764–1851), vicar of Woolavington, Somerset, he was born at his father's vicarage on 19 November 1813; John Jacob (1812–1858) was his brother, and Sir George le Grand Jacob a cousin. He entered
Addiscombe College
The East India Company Military Seminary was a British military academy at Addiscombe, Surrey, in what is now the London Borough of Croydon. It opened in 1809 and closed in 1861. Its purpose was to train young officers to serve in the East India ...
as an
East India Company
The East India Company (EIC) was an English, and later British, joint-stock company founded in 1600 and dissolved in 1874. It was formed to trade in the Indian Ocean region, initially with the East Indies (the Indian subcontinent and South ...
Bombay
Mumbai (, ; also known as Bombay — the official name until 1995) is the capital city of the Indian state of Maharashtra and the ''de facto'' financial centre of India. According to the United Nations, as of 2018, Mumbai is the second-m ...
in 1831, he spent some years with the
Great trigonometrical survey
The Great Trigonometrical Survey was a project that aimed to survey the entire Indian subcontinent with scientific precision. It was begun in 1802 by the British infantry officer William Lambton, under the auspices of the East India Company.Gi ...
Pune
Pune (; ; also known as Poona, ( the official name from 1818 until 1978) is one of the most important industrial and educational hubs of India, with an estimated population of 7.4 million As of 2021, Pune Metropolitan Region is the largest i ...
in 1842. Bad health meant he took sick leave at the Cape of Good Hope. He became assistant to
Andrew Scott Waugh
Major General Sir Andrew Scott Waugh (3 February 1810 – 21 February 1878) was a British army officer and Surveyor General of India who worked in the Great Trigonometrical Survey. He served under Sir George Everest and succeeded him in 1843. ...
, but again fell ill. In 1843 he went back to England on furlough, married in 1844, and returned in 1845 to India, but left the company's service on attaining the rank of captain in the Bombay engineers.
Jacob concentrated on science, and was appointed in December 1848 director of the Madras Observatory. In poor health, he was sent home on sick leave in 1854–5, and again in 1858–9. A transit-circle by William Simms arrived from England in March 1858, a month before he finally left the observatory, resigning on 13 October 1859.
For the
solar eclipse of July 18, 1860
A total solar eclipse occurred on July 18, 1860. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon's ...
, Jacob joined the official expedition to Spain aboard the steamer ''Himalaya''. His project of erecting a mountain observatory at Pune was funded by parliament in 1862. He engaged to work there for three years with a 9-inch equatorial, his own purchase from Noël Paymal Lerebours, and landed at Bombay on 8 August, but died on reaching Pune on 16 August 1862, aged 48. He was elected a fellow of the
Royal Astronomical Society
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in 1849.
Works
Jacob presented to the Royal Astronomical Society in 1848 a catalogue of 244 double stars, observed at Pune with a 5-foot Dollond's equatorial. He computed orbits for several noted binaries, and discovered in 1847 that
Pi Scorpii
Pi Scorpii or π Scorpii, is a triple star system in the southern constellation of Scorpius. With a combined apparent magnitude of 2.9, it can be easily seen with the naked eye. Parallax measurements yield an estimated distance of around ...
is a triple star.
In the ''Madras Observations'' for 1848–52 Jacob published a ''Subsidiary Catalogue of 1,440 Stars selected from the British Association Catalogue''. His re-observation of 317 stars from the same collection in 1853–7 showed that large proper motions had been erroneously attributed to them; the instruments used were a 5-foot transit and a 4-foot mural circle, both by Dollond. The same volume contained 998 measures of 250 double stars made with an equatorial of 6.3 inches aperture constructed for Jacob by Lerebours in 1850. Attempted determinations of stellar parallax gave only the ostensible result of a parallax of 0″.06 for
Alpha Herculis
Alpha Herculis (α Herculis, abbreviated Alpha Her, α Her), also designated 64 Herculis, is a multiple star system in the constellation of Hercules. Appearing as a single point of light to the naked eye, it is resolvable into a number ...
.
From his measures of the Saturnian and Jovian systems, printed at the expense of the Indian government, Jacob deduced elements for the
satellites of Saturn
The moons of Saturn are numerous and diverse, ranging from tiny moonlets only tens of meters across to enormous Titan, which is larger than the planet Mercury. Saturn has 83 moons with confirmed orbits that are not embedded in its rings—of wh ...
and a corrected mass for
Jupiter
Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...
; and he noticed in 1852, almost simultaneously with
William Lassell
William Lassell (18 June 1799 – 5 October 1880) was an English merchant and astronomer.James Breen in 1861.
His results of magnetic observations at Madras (1846–1850) were published by Jacob in 1854; those made under his superintendence (1851–1855) by
N. R. Pogson
Norman Robert Pogson, CIE (23 March 1829 – 23 June 1891) was an English astronomer who worked in India at the Madras observatory. He discovered several minor planets and made observations on comets. He introduced a mathematical scale of ste ...
in 1884. Jacob published in 1850 some
Singapore
Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...
meteorological observations (1841–5), and in 1857 those at Dodabetta (1851–5).
While in England in 1855 Jacob wrote ''"A few more words on the'' ''Plurality of Worlds''" in which he suggested life on other planets ("probably that some of the known planets are inhabited, not very improbable that all of them are"), and described his computation of stellar orbits for the Royal Astronomical Society. Jacob posited that apparent orbital anomalies in the binary star 70 Ophiuchi might be caused by an exoplanet. While these anomalies are now thought to have other causes, this was the first serious claim by an astronomer to have detected an exoplanet using scientific methods: 100 years before the first exoplanet was conclusively detected and well before the science of exoplanets was even in its infancy. Professor David Kipping states that the ‘“claim is so remarkable because Jacob was making tiny measurements (80 milliarc seconds or 22 millionths of a degree) with the naked eye, at a time when he wasn’t even sure whether Newton’s law of gravity held sway in distant parts of the galaxy. While Jacob... was ultimately proved wrong, he had the audacity to try.”Professor David Kipping, Columbia University Dept of Astronomy, Cool Worlds video series
Family
Jacob married in 1844, Elizabeth, fourth daughter of Mathew Coates of
Gainsborough Gainsborough or Gainsboro may refer to:
Places
* Gainsborough, Ipswich, Suffolk, England
** Gainsborough Ward, Ipswich
* Gainsborough, Lincolnshire, a town in England
** Gainsborough (UK Parliament constituency)
* Gainsborough, New South Wales, ...
, who survived him. They had six sons and two daughters.