Charles Pritchard
Encyclopedia
Charles Pritchard was a British
astronomer
.
He was born at Alberbury
, Shropshire
. At sixteen he was enrolled as a sizar
at St John's College, Cambridge
, graduating in 1830 as fourth wrangler. In 1832 he was elected a fellow of his college, and in the following year he was ordained, and became head of a private school at Stockwell
. From 1834 to 1862 he was headmaster of Clapham grammar school
. He then retired to Freshwater
, in the Isle of Wight
, and took an active interest in the affairs of the Royal Astronomical Society
, of which he became honorary secretary in 1862 and president in 1866. His sister, Margaret died this same year.
His career as a professional astronomer began in 1870, when he was elected Savilian professor of astronomy at the University of Oxford
. At his request the university decided to build a fine equatorial telescope
for the instruction of his class and for purposes of research, a scheme which, as a result of Warren de la Rue
's munificent gift of instruments from his private observatory at Cranford, expanded into the establishment of the new university observatory
. By De la Rue's advice, Pritchard began his career there with a determination of the physical libration
of the moon
, or the nutation
of its axis.
In 1882 Pritchard commenced a systematic study of stellar photometry
. For this purpose he employed an instrument known as the "wedge photometer", with which he measured the relative brightness of 2,784 stars between the North Pole
and about -10° declination
. The results were published in 1885 in his Uranometria Nova Oxoniensis, and their importance was recognized by the bestowal in 1886 upon him, conjointly with Professor Pickering
, of the Gold Medal of the Royal Astronomical Society
.
He then decided to experiment with applying photography
to the determination of stellar parallax
. With the object of testing the capabilities of the method, he took for his first essay the well-known star 61 Cygni
, and his results agreed so well with those previously attained that he undertook the systematic measurement of the parallaxes of second-magnitude stars, and published the outcome in the third and fourth volumes of the Publications of the Oxford University Observatory. Although some lurking errors impaired the authority of the concluded parallaxes this work ranks as a valuable contribution to astronomy, since it showed the possibility of employing photography in such delicate investigations.
When an international survey of the heavens was proposed, the zone between 25° and 31° north declination was allotted to him, and at the time of his death some progress had been made in recording its included stars. Pritchard became a fellow of New College, Oxford
, in 1883, and an honorary fellow of St John's College, Cambridge
, in 1886. He was elected a fellow of the Royal Society
in 1840, and in 1892 was awarded one of the royal medals for his work on photometry
and stellar parallax
.
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
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...
.
He was born at Alberbury
Alberbury
Alberbury is a village in Shropshire, England, located 9 miles north-west of Shrewsbury. Alberbury Castle is at the centre of the village as is Loton Hall and the attached deer park. The River Severn runs just north of the village. Most of the village is within a designated conservation area and...
, Shropshire
Shropshire
Shropshire is a county in the West Midlands region of England. For Eurostat purposes, the county is a NUTS 3 region and is one of four counties or unitary districts that comprise the "Shropshire and Staffordshire" NUTS 2 region. It borders Wales to the west...
. At sixteen he was enrolled as a sizar
Sizar
At Trinity College, Dublin and the University of Cambridge, a sizar is a student who receives some form of assistance such as meals, lower fees or lodging during his or her period of study, in some cases in return for doing a defined job....
at St John's College, Cambridge
St John's College, Cambridge
St John's College is a constituent college of the University of Cambridge. The college's alumni include nine Nobel Prize winners, six Prime Ministers, three archbishops, at least two princes, and three Saints....
, graduating in 1830 as fourth wrangler. In 1832 he was elected a fellow of his college, and in the following year he was ordained, and became head of a private school at Stockwell
Stockwell
Stockwell is a district in inner south west London, England, located in the London Borough of Lambeth.It is situated south south-east of Charing Cross. Brixton, Clapham, Vauxhall and Kennington all border Stockwell...
. From 1834 to 1862 he was headmaster of Clapham grammar school
Grammar school
A grammar school is one of several different types of school in the history of education in the United Kingdom and some other English-speaking countries, originally a school teaching classical languages but more recently an academically-oriented secondary school.The original purpose of mediaeval...
. He then retired to Freshwater
Freshwater, Isle of Wight
Freshwater is a large village and civil parish at the western end of the Isle of Wight, England. Freshwater Bay is a small cove on the south coast of the Island which also gives its name to the nearby part of Freshwater....
, in the Isle of Wight
Isle of Wight
The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...
, and took an active interest in the affairs of the Royal Astronomical Society
Royal Astronomical Society
The Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...
, of which he became honorary secretary in 1862 and president in 1866. His sister, Margaret died this same year.
His career as a professional astronomer began in 1870, when he was elected Savilian professor of astronomy at the University of Oxford
University of Oxford
The University of Oxford is a university located in Oxford, United Kingdom. It is the second-oldest surviving university in the world and the oldest in the English-speaking world. Although its exact date of foundation is unclear, there is evidence of teaching as far back as 1096...
. At his request the university decided to build a fine equatorial telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
for the instruction of his class and for purposes of research, a scheme which, as a result of Warren de la Rue
Warren de la Rue
Warren De la Rue was a British astronomer and chemist, most famous for his pioneering work in astronomical photography.-Biography:...
's munificent gift of instruments from his private observatory at Cranford, expanded into the establishment of the new university observatory
Observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...
. By De la Rue's advice, Pritchard began his career there with a determination of the physical libration
Libration
In astronomy, libration is an oscillating motion of orbiting bodies relative to each other, notably including the motion of the Moon relative to Earth, or of Trojan asteroids relative to planets.-Lunar libration:...
of the moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
, or the nutation
Nutation
Nutation is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behavior of a mechanism...
of its axis.
In 1882 Pritchard commenced a systematic study of stellar photometry
Photometry (astronomy)
Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation...
. For this purpose he employed an instrument known as the "wedge photometer", with which he measured the relative brightness of 2,784 stars between the North Pole
North Pole
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets its surface...
and about -10° declination
Declination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
. The results were published in 1885 in his Uranometria Nova Oxoniensis, and their importance was recognized by the bestowal in 1886 upon him, conjointly with Professor Pickering
Edward Charles Pickering
Edward Charles Pickering was an American astronomer and physicist, brother of William Henry Pickering.Along with Carl Vogel, Pickering discovered the first spectroscopic binary stars. He wrote Elements of Physical Manipulations .Pickering attended Boston Latin School, and received his B.S. from...
, of the Gold Medal of the Royal Astronomical Society
Gold Medal of the Royal Astronomical Society
-History:In the early years, more than one medal was often awarded in a year, but by 1833 only one medal was being awarded per year. This caused a problem when Neptune was discovered in 1846, because many felt an award should jointly be made to John Couch Adams and Urbain Le Verrier...
.
He then decided to experiment with applying photography
Photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
to the determination of stellar parallax
Stellar parallax
Stellar parallax is the effect of parallax on distant stars in astronomy. It is parallax on an interstellar scale, and it can be used to determine the distance of Earth to another star directly with accurate astrometry...
. With the object of testing the capabilities of the method, he took for his first essay the well-known star 61 Cygni
61 Cygni
61 Cygni,Not to be confused with 16 Cygni, a more distant system containing two G-type stars harboring the gas giant planet 16 Cygni Bb. sometimes called Bessel's Star or Piazzi's Flying Star, is a binary star system in the constellation Cygnus...
, and his results agreed so well with those previously attained that he undertook the systematic measurement of the parallaxes of second-magnitude stars, and published the outcome in the third and fourth volumes of the Publications of the Oxford University Observatory. Although some lurking errors impaired the authority of the concluded parallaxes this work ranks as a valuable contribution to astronomy, since it showed the possibility of employing photography in such delicate investigations.
When an international survey of the heavens was proposed, the zone between 25° and 31° north declination was allotted to him, and at the time of his death some progress had been made in recording its included stars. Pritchard became a fellow of New College, Oxford
New College, Oxford
New College is one of the constituent colleges of the University of Oxford in the United Kingdom.- Overview :The College's official name, College of St Mary, is the same as that of the older Oriel College; hence, it has been referred to as the "New College of St Mary", and is now almost always...
, in 1883, and an honorary fellow of St John's College, Cambridge
St John's College, Cambridge
St John's College is a constituent college of the University of Cambridge. The college's alumni include nine Nobel Prize winners, six Prime Ministers, three archbishops, at least two princes, and three Saints....
, in 1886. He was elected a fellow of the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
in 1840, and in 1892 was awarded one of the royal medals for his work on photometry
Photometry (astronomy)
Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation...
and stellar parallax
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. The term is derived from the Greek παράλλαξις , meaning "alteration"...
.
External links
- Awarding of RAS gold medal
- PRITCHARD, CHARLES, Dictionary of national biography, vol. 16, 1909, pages 403-406