Friedrich II. Graf von Hahn (July 27, 1742 – October 9, 1805) was a German nobleman, a philosopher and astronomer born in Neuhaus, Holstein,

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

. He suggested the Doppler effect before Doppler.

Career

Observatory

In 1793 Von Hahn started the construction of a private observatory, the first in

Mecklenburg Mecklenburg (; nds, label= Low German, Mękel(n)borg ) is a historical region in northern Germany comprising the western and larger part of the federal-state Mecklenburg-Western Pomerania. The largest cities of the region are Rostock, Schweri ...

, which was well equipped. He owned some of the largest mirrors made by

William Herschel Frederick William Herschel (; german: Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline ...

and precision instruments for determining the position of stars. He used his instruments in order to observe various

stars A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth ma ...

, including the

sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

, planets, and

nebulae A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust. Nebulae are often star-forming region ...

Discoveries and observations

Von Hahn spent a significant amount of time observing the nebula NGC 3242, originally discovered by William Herschel. He documented the change in position and shape of the nebula over the course of a year. He also observed the Mira star system, which he had erroneously thought to be a nebula. The discovery Von Hahn in best known for is his 1800 discovery of the central star in the Ring Nebula M 57, in the constellation,

Lyra Lyra (; Latin for lyre, from Greek ''λύρα'') is a small constellation. It is one of the 48 listed by the 2nd century astronomer Ptolemy, and is one of the modern 88 constellations recognized by the International Astronomical Union. Lyra wa ...

. This discovery contributed to Antoine Darquier de Pellepoix's discovery of the nebula 21 years earlier.

Death and memory

He died in

Remplin Remplin is a village and a former municipality in the Mecklenburgische Seenplatte district, in Mecklenburg-Vorpommern, Germany. Since 7 June 2009, it is part of the municipality Malchin. Palace Complex The town includes the remains of a once lar ...

, Germany on October 9, 1805 at the age of 63. After his death, his son, the "theatrical count" and father of author

Ida, Countess von Hahn-Hahn Countess Ida von Hahn-Hahn (german: link=no, Ida Gräfin von Hahn-Hahn; 22 June 1805 – 12 January 1880) was a German author from a wealthy family who lost their fortune because of her father's eccentric spending. She defied convention by living ...

, squandered his fortune and all books and instruments were sold. The best instruments were bought by

Friedrich Wilhelm Bessel Friedrich Wilhelm Bessel (; 22 July 1784 – 17 March 1846) was a German astronomer, mathematician, physicist, and geodesist. He was the first astronomer who determined reliable values for the distance from the sun to another star by the method ...

for the new observatory in

Königsberg Königsberg (, ) was the historic Prussian city that is now Kaliningrad, Russia. Königsberg was founded in 1255 on the site of the ancient Old Prussian settlement ''Twangste'' by the Teutonic Knights during the Northern Crusades, and was name ...

. One instrument is on display in the

Deutsches Museum The Deutsches Museum (''German Museum'', officially (English: ''German Museum of Masterpieces of Science and Technology'')) in Munich, Germany, is the world's largest museum of science and technology, with about 28,000 exhibited objects from ...

in Munich. His herschelian telescope was acquired in 1812 by the Neapolitan astronomer, Federigo Zuccari, for the new

Capodimonte Observatory The Astronomical Observatory of Capodimonte ( it, Osservatorio Astronomico di Capodimonte, italic=no) is the Neapolitan department of Istituto Nazionale di Astrofisica (National Institute for Astrophysics, INAF), the most important Italian institu ...

. Now th
mirror
of this telescope is part of the Observator
Museum
collection. He is honoured together with

Otto Hahn Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the fields of radioactivity and radiochemistry. He is referred to as the father of nuclear chemistry and father of nuclear fission. Hahn and Lise Meitner ...

by the lunar crater Hahn.

References

External links

Remplin Observatory
{{DEFAULTSORT:Hahn, Friedrich von 1742 births 1805 deaths 18th-century German astronomers German philosophers People from the Duchy of Holstein German male writers