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Alfred Harrison Joy
Alfred Harrison Joy (September 23, 1882 in Greenville, Illinois – April 18, 1973 in Pasadena, California) was an astronomer best known for his work on stellar distances, the radial motion of stars, and variable stars. A crater on the moon has been named in his honor. Early years He was born in Greenville, Illinois, the son of F.P. Joy, a prominent clothing merchant in Greenville and one-time mayor of the town.Allan H. Keith ''Historical Stories: About Greenville and Bond County, IL'' Consulted on August 15, 2007. He received a BA from Greenville College in 1903 and an MA from Oberlin College the next year. Career After graduating, Joy went on to work at the American University of Beirut in the Syrian Protestant College as a professor of astronomy and the director of the observatory. He was forced to return to the U.S. in 1915 because of World War I. In the United States, he worked at the Mount Wilson Observatory from 1915 to 1952. There, he and his colleagues ascertained the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenville, Illinois
: Greenville is a city in Bond County, Illinois, United States, east of St. Louis. The population as of the 2020 census was 7,083, up from 7,000 at the 2010 census. It is the county seat of Bond County. Greenville is part of the St. Louis Metropolitan Statistical Area. It is also considered part of the Metro East region of Illinois. Greenville celebrated its Bicentennial in 2015 as one of the oldest communities in Illinois. It is home to Greenville University, the Richard Bock Museum, the American Farm Heritage Museum, the Armed Forces Museum and the Demoulin Museum and a federal prison, Federal Correctional Institution, Greenville (FCI Greenville). It is also home to internationally known companies, including Nevco Scoreboard, the largest privately owned scoreboard company in the world, and DeMoulin Brothers, the world's oldest and largest manufacturer of band uniforms. History Greenville was founded by George Davidson in 1815 in what was then the Illinois Territory, when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absolute Magnitude
Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it were viewed from a distance of exactly , without Extinction (astronomy), extinction (or dimming) of its light due to absorption by Interstellar medium, interstellar matter and cosmic dust. By hypothetically placing all objects at a standard reference distance from the observer, their luminosities can be directly compared among each other on a magnitude scale. As with all astronomical magnitude (astronomy), magnitudes, the absolute magnitude can be specified for different wavelength ranges corresponding to specified Filter (optics), filter bands or passbands; for stars a commonly quoted absolute magnitude is the absolute visual magnitude, which uses the visual (V) band of the spectrum (in the UBV phot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Astronomers
American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, people who self-identify their ancestry as "American" ** American English, the set of varieties of the English language native to the United States ** Native Americans in the United States, indigenous peoples of the United States * American, something of, from, or related to the Americas, also known as "America" ** Indigenous peoples of the Americas * American (word), for analysis and history of the meanings in various contexts Organizations * American Airlines, U.S.-based airline headquartered in Fort Worth, Texas * American Athletic Conference, an American college athletic conference * American Recordings (record label), a record label previously known as Def American * American University, in Washington, D.C. Sports teams Soccer * B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1973 Deaths
Events January * January 1 - The United Kingdom, the Republic of Ireland and Denmark enter the European Economic Community, which later becomes the European Union. * January 15 – Vietnam War: Citing progress in peace negotiations, U.S. President Richard Nixon announces the suspension of offensive action in North Vietnam. * January 17 – Ferdinand Marcos becomes President for Life of the Philippines. * January 20 – Richard Nixon is sworn in for a second term as President of the United States. Nixon is the only person to have been sworn in twice as President ( 1969, 1973) and Vice President of the United States ( 1953, 1957). * January 22 ** George Foreman defeats Joe Frazier to win the heavyweight world boxing championship. ** A Royal Jordanian Boeing 707 flight from Jeddah crashes in Kano, Nigeria; 176 people are killed. * January 27 – U.S. involvement in the Vietnam War ends with the signing of the Paris Peace Accords. February * February 8 – A militar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1882 Births
Year 188 (CLXXXVIII) was a leap year starting on Monday of the Julian calendar. At the time, it was known in the Roman Empire as the Year of the Consulship of Fuscianus and Silanus (or, less frequently, year 941 ''Ab urbe condita''). The denomination 188 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Publius Helvius Pertinax becomes pro-consul of Africa from 188 to 189. Japan * Queen Himiko (or Shingi Waō) begins her reign in Japan (until 248). Births * April 4 – Caracalla (or Antoninus), Roman emperor (d. 217) * Lu Ji (or Gongji), Chinese official and politician (d. 219) * Sun Shao, Chinese general of the Eastern Wu state (d. 241) Deaths * March 17 – Julian, pope and patriarch of Alexandria * Fa Zhen (or Gaoqing), Chinese scholar (b. AD 100) * Lucius Antistius Burrus, Roman politician (executed) * Ma Xiang, Chi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bruce Medal
The Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was first awarded in 1898. List of Bruce Medalists SourceAstronomical Society of the Pacific * 1898 – Simon Newcomb * 1899 – Arthur Auwers * 1900 – David Gill * 1902 – Giovanni V. Schiaparelli * 1904 – William Huggins * 1906 – Hermann Carl Vogel * 1908 – Edward C. Pickering * 1909 – George William Hill * 1911 – Henri Poincaré * 1913 – Jacobus C. Kapteyn * 1914 – Oskar Backlund * 1915 – William Wallace Campbell * 1916 – George Ellery Hale * 1917 – Edward Emerson Barnard * 1920 – Ernest W. Brown * 1921 – Henri A. Deslandres * 1922 – Frank W. Dyson * 1923 – Benjamin Baillaud * 1924 – Arthur Stanley Eddington * 1925 – Henry Norris Russell * 1926 – Robert G. Aitken * 1927 – Herbert Hall Turner * 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Effect
The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession. The reason for the Doppler effect is that when the source of the waves is moving towards the observer, each successive wave crest is emitted from a position closer to the observer than the crest of the previous wave. Therefore, each wave takes slightly less time to reach the observer than the previous wave. Hence, the time between the arrivals of successive wave crests at the observer is reduced, causing an increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T Tauri Star
T Tauri stars (TTS) are a class of variable stars that are less than about ten million years old. This class is named after the prototype, T Tauri, a young star in the Taurus star-forming region. They are found near molecular clouds and identified by their optical variability and strong chromospheric lines. T Tauri stars are pre-main-sequence stars in the process of contracting to the main sequence along the Hayashi track, a luminosity–temperature relationship obeyed by infant stars of less than 3 solar masses () in the pre-main-sequence phase of stellar evolution. It ends when a star of or larger develops a radiative zone, or when a smaller star commences nuclear fusion on the main sequence. History While T Tauri itself was discovered in 1852, the T Tauri class of stars were initially defined by Alfred Harrison Joy in 1945. Characteristics T Tauri stars comprise the youngest visible F, G, K and M spectral type stars (). Their surface temperatures are similar to those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Type
In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grating into a spectrum exhibiting the Continuum (spectrum), rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The ''spectral class'' of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature. Most stars are currently classified under the Morgan–Keenan (MK) system using the letters ''O'', ''B'', ''A'', ''F'', ''G'', ''K'', and ''M'', a sequence from the hottest (''O'' type) to the coo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pasadena, California
Pasadena ( ) is a city in Los Angeles County, California, northeast of downtown Los Angeles. It is the most populous city and the primary cultural center of the San Gabriel Valley. Old Pasadena is the city's original commercial district. Its population was 138,699 at the 2020 census, making it the 44th largest city in California and the ninth-largest city in Los Angeles County. Pasadena was incorporated on June 19, 1886, becoming one of the first cities to be incorporated in what is now Los Angeles County, following the city of Los Angeles (April 4, 1850). Pasadena is known for hosting the annual Rose Bowl football game and Tournament of Roses Parade. It is also home to many scientific, educational, and cultural institutions, including Caltech, Pasadena City College, Kaiser Permanente Bernard J. Tyson School of Medicine, Fuller Theological Seminary, ArtCenter College of Design, the Pasadena Playhouse, the Ambassador Auditorium, the Norton Simon Museum, and the USC Pacif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Wilson Observatory
The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles. The observatory contains two historically important telescopes: the Hooker telescope, which was the largest aperture telescope in the world from its completion in 1917 to 1949, and the 60-inch telescope which was the largest operational telescope in the world when it was completed in 1908. It also contains the Snow solar telescope completed in 1905, the 60 foot (18 m) solar tower completed in 1908, the 150 foot (46 m) solar tower completed in 1912, and the CHARA array, built by Georgia State University, which became fully operational in 2004 and was the largest optical interferometer in the world at its completion. Due to the inversion layer that traps warm air and smog over Los Angeles, Mount Wilson has steadier air than any other location in Nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
