Johannes Franz Hartmann (11 January 1865 – 13 September 1936) was a German

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate caus ...

and

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

. In 1904, while studying the

spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...

of Delta Orionis he noticed that most of the spectrum had a shift, except the

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

lines, which he interpreted as indicating the presence of

interstellar medium In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstella ...

. Asimov, ''

Asimov's Biographical Encyclopedia of Science and Technology ''Asimov's Biographical Encyclopedia of Science and Technology'' is a history of science by Isaac Asimov, written as the biographies of initially 1000 scientists and later with over 1500 entries. Organized chronologically, beginning with Imhotep ( ...

'' 2nd Revised edition He was the director of the

La Plata Astronomical Observatory The La Plata Astronomical Observatory ( es, Observatorio Astronómico de La Plata) is an observatory located in the city of La Plata, capital of the province of Buenos Aires, Argentina. Its IAU code is 839. History La Plata was a planned city ...

, Argentina, from November 1922 to May 1934, and was also known under the name Juan Hartmann. He oriented the work of the observatory towards

astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline said, Astrophysics "seeks to ascertain the nature of the h ...

and discovered the three

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

s of the main-belt, 965 Angelica, 1029 La Plata and 1254 Erfordia at La Plata between 1921 and 1932. His doctorate was from the

University of Leipzig Leipzig University (german: Universität Leipzig), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 Decemb ...

in 1891 on lunar eclipses. The lunar crater '' Hartmann'' on the

far side ''The Far Side'' is a single-panel comic created by Gary Larson and syndicated by Chronicle Features and then Universal Press Syndicate, which ran from December 31, 1979, to January 1, 1995 (when Larson retired as a cartoonist). Its surrealis ...

of the Moon was named in his honor. Note, however, that the asteroid 3341 Hartmann was named after

William K. Hartmann William Kenneth Hartmann (born June 6, 1939) is a noted planetary scientist, artist, author, and writer. He was the first to convince the scientific mainstream that the Earth had once been hit by a planet sized body (Theia), creating both the ...

and is unrelated to him. Delegates to the Fourth Conference International Union for Cooperation in Solar Research at Mount Wilson Observatory

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External links

*
Lista de cientificos

1865 births 1936 deaths 19th-century German astronomers Discoverers of asteroids * 20th-century German physicists 20th-century German astronomers German expatriates in Argentina 19th-century German physicists {{Germany-astronomer-stub

See also

References

External links