Peder Horrebow
Encyclopedia
Peder [Nielsen] Horrebow (Horrebov) (14 May 1679 – 15 April 1764) was a Danish
astronomer. Born in Løgstør
, Jutland
to a poor family of fishermen, Horrebow entered the University of Copenhagen
in 1703. He worked his way through grammar school and university by virtue of his technical knowledge: he repaired mechanical and musical instruments and cut seals. He received his MA from the university in 1716, and his MD in 1725. From 1703 to 1707, he served as an assistant to Ole Rømer and lived in Rømer's home. He worked as a household tutor from 1707 to 1711 to a Danish baron
, and entered the governmental bureaucracy as an excise
writer in 1711.
After repeatedly petitioning King Frederick IV
, Horrebow became professor of mathematics at the University of Copenhagen in 1714. He also became director of the university's observatory
(called the Rundetårn
, "the Round Tower"). His son Christian
succeeded him in this position (Horrebow had a total of 20 children).
In 1728, the great fire of Copenhagen
destroyed all of the papers and observations made by Rømer, who had died in 1710. Horrebow wrote the Basis Astronomiae (1734–35), which describes the scientific achievements made by Rømer. Horrebow's own papers and instruments were destroyed in the same fire. Horrebow was given a special grant from the government to repair the observatory and instruments. Horrebow received further support from a wealthy patron.
Horrebow invented a way to determine a place's latitude
from the stars. The method fixed latitude by observing differences of zenith
distances of stars culminating within a short time of each other, and at nearly the same altitude, on opposite sides of the zenith. The method was soon forgotten despite its value until it was rediscovered by the American Andrew Talcott
in 1833. It is now called the Horrebow-Talcott Method.
He wrote on navigation
and determined the sun parallax
, 9", an approximative solution to the Kepler equation. Horrebow also learned how to correct inherent flaws in instruments. This preceded Tobias Mayer
's theory of correction of 1756.
Horrebow was a member of a number of scientific societies, including the Académie des Sciences (from 1746). He also worked as a medical doctor and as an academic notary (from 1720).
He died in Copenhagen.
The crater Horrebow
on the Moon
is named after him.
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
astronomer. Born in Løgstør
Løgstør
Løgstør is a town with a population of 4,357 and a former municipality in Region Nordjylland on the Jutland Peninsula in northern Denmark. The municipality, including the island of Livø, covered an area of , and had a total population of 10,270...
, Jutland
Jutland
Jutland , historically also called Cimbria, is the name of the peninsula that juts out in Northern Europe toward the rest of Scandinavia, forming the mainland part of Denmark. It has the North Sea to its west, Kattegat and Skagerrak to its north, the Baltic Sea to its east, and the Danish–German...
to a poor family of fishermen, Horrebow entered the University of Copenhagen
University of Copenhagen
The University of Copenhagen is the oldest and largest university and research institution in Denmark. Founded in 1479, it has more than 37,000 students, the majority of whom are female , and more than 7,000 employees. The university has several campuses located in and around Copenhagen, with the...
in 1703. He worked his way through grammar school and university by virtue of his technical knowledge: he repaired mechanical and musical instruments and cut seals. He received his MA from the university in 1716, and his MD in 1725. From 1703 to 1707, he served as an assistant to Ole Rømer and lived in Rømer's home. He worked as a household tutor from 1707 to 1711 to a Danish baron
Baron
Baron is a title of nobility. The word baron comes from Old French baron, itself from Old High German and Latin baro meaning " man, warrior"; it merged with cognate Old English beorn meaning "nobleman"...
, and entered the governmental bureaucracy as an excise
Excise
Excise tax in the United States is a indirect tax on listed items. Excise taxes can be and are made by federal, state and local governments and are far from uniform throughout the United States...
writer in 1711.
After repeatedly petitioning King Frederick IV
Frederick IV of Denmark
Frederick IV was the king of Denmark and Norway from 1699 until his death. Frederick was the son of King Christian V of Denmark and Norway and Charlotte Amalie of Hesse-Kassel .-Foreign affairs:...
, Horrebow became professor of mathematics at the University of Copenhagen in 1714. He also became director of the university's 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...
(called the Rundetårn
Rundetårn
The Rundetårn is a 17th-century tower located in central Copenhagen, Denmark. One of the many architectural projects of Christian IV, it was built as an astronomical observatory...
, "the Round Tower"). His son Christian
Christian Horrebow
Christian Pedersen Horrebow was a Danish astronomer of the 18th century. He was a son of Peder Horrebow, whom he succeeded as director of the observatory associated with the University of Copenhagen....
succeeded him in this position (Horrebow had a total of 20 children).
In 1728, the great fire of Copenhagen
Copenhagen Fire of 1728
The Copenhagen Fire of 1728 was the largest fire in the history of Copenhagen, Denmark. It began on the evening of October 20, 1728, and continued to burn until the morning of October 23. It destroyed approximately 28% of the city , left 20% of the population homeless, and the reconstruction lasted...
destroyed all of the papers and observations made by Rømer, who had died in 1710. Horrebow wrote the Basis Astronomiae (1734–35), which describes the scientific achievements made by Rømer. Horrebow's own papers and instruments were destroyed in the same fire. Horrebow was given a special grant from the government to repair the observatory and instruments. Horrebow received further support from a wealthy patron.
Horrebow invented a way to determine a place's latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
from the stars. The method fixed latitude by observing differences of zenith
Zenith
The zenith is an imaginary point directly "above" a particular location, on the imaginary celestial sphere. "Above" means in the vertical direction opposite to the apparent gravitational force at that location. The opposite direction, i.e...
distances of stars culminating within a short time of each other, and at nearly the same altitude, on opposite sides of the zenith. The method was soon forgotten despite its value until it was rediscovered by the American Andrew Talcott
Andrew Talcott
Andrew Talcott was an American civil engineer and close friend of Civil War General Robert E. Lee. While serving as a Confederate States of America Colonel and the State Engineer of Virginia, he was arrested and made prisoner of war during that conflict.-Early life:Talcott was born on April 20,...
in 1833. It is now called the Horrebow-Talcott Method.
He wrote on navigation
Navigation
Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...
and determined the sun 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"...
, 9", an approximative solution to the Kepler equation. Horrebow also learned how to correct inherent flaws in instruments. This preceded Tobias Mayer
Tobias Mayer
Tobias Mayer was a German astronomer famous for his studies of the Moon.He was born at Marbach, in Württemberg, and brought up at Esslingen in poor circumstances. A self-taught mathematician, he had already published two original geometrical works when, in 1746, he entered J.B. Homann's...
's theory of correction of 1756.
Horrebow was a member of a number of scientific societies, including the Académie des Sciences (from 1746). He also worked as a medical doctor and as an academic notary (from 1720).
He died in Copenhagen.
The crater Horrebow
Horrebow (crater)
Horrebow is a lunar impact crater that is located along the northern shore of Mare Frigoris, just to the south of the walled plain J. Herschel. To the west of Horrebow is the crater Robinson....
on 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...
is named after him.