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# Astronomers

  (190-120 B.C.) Hipparchus was a Greek. He made the first star catalogue. A star catalogue is a list of stars which tells where each one is in the sky.
  (A.D. 100-170) Ptolemy was also a Greek. He made a list of constellations, or groups of stars. The 48 constellations he named did not cover the whole sky, but no one dared add to the list for more than a thousand years. Ptolemy thought that the earth stood still and that all the heavenly bodies traveled around it. Of course, this idea was wrong, but many of his ideas were right. An astronomy book he wrote was used for centuries.
  (1473-1573) Copernicus (ko per ne kus) was a Polish astronomer. He wrote a book that completely changed the study of astronomy. In it he explained that the earth is not the center of the universe. He said that the earth is one of the sun’s family of planets and that it spins on its axis as it travels around the sun. All the astronomers of today agree with those ideas.
  (1546-1601) Tycho Brahe (Brah e) a Dane, was the first astronomer to study the stars called "novae." Novae are stars that suddenly become very much brighter and then fade. Brahe also watched the planets and kept a careful record of where they were in the sky.
  (1564-1642) Galileo the famous Italian scientist was the first tostudy the sky with a telescope. He discovered that there are mountains on the moon and sunspots on the sun. He saw four of the moons of Jupiter.
  (1629-1695) Christian Huyghens (Hoy kens) was a Dutch astronomer. He discovered the rings of Saturn and found out a great deal about Mars.
  (1642-1727) Sir Isaac Newton, the most famous English scientist of all time, wondered what keeps the moons and planets in their paths. In trying to find out, he discovered the laws of gravity and motion.
  (1656-1742) Halley, Edmond lived in England in Newton’s time. He became famous for his study of comets. Halley’s comet is named for him. He was made Astronomer Royal in 1721 and began an 18-year study of the complete revolution of the moon.
  (1693-1762), Bradley, James British astronomer, born in England. In 1729 his theory of the aberration of the fixed stars, containing the important discovery of the aberration of light, was published. Bradley also discovered the vibration of the earth's axis.
  (1731-1806), Banneker, Benjamin African American farmer, self-taught mathematician and astronomer. Banneker was born in Maryland and spent most of his life on the tobacco farm he inherited from his father. He helped survey the site of the national capital between 1791 and 1793.
  (1758-1840), Olbers, Heinrich Wilhelm Matthäus a German physician and astronomer, born in Abergen. In 1779 he devised a method, still employed by astronomers, for calculating the orbits of comets. (Olbers discovered several comets, the first, named after him, in 1815.) In 1781 he identified Uranus as a planet rather than as a comet, as had previously been assumed. He discovered the asteroid Belt in 1802 and first proposed that all asteroids are fragments of a shattered planet that formerly revolved around the sun. He observed, in 1826, that the night sky should be regularly lit up if the universe were infinite and similar, with stars in every direction.
  (1784-1846), Bessel, Friedrich Wilhelm German astronomer and mathematician, best known for making the first accurate measurement of the distance to a star. Born in Minden. He established the uniform system for computing star positions that is still in use. From 1821 to 1833 he accurately determined the positions of stars to the ninth magnitude, bringing the number of stars so cataloged to 50,000.
  (1799-1875), Argelander, Friedrich Wilhelm August German astronomer, who compiled a catalog of more than 300,000 stars over a 25-year period. Argelander was born in Memel, Prussia.
  (1825-1865), Bond, George Phillips American astronomer, a pioneer of photographic astronomy. With his father, he established the Harvard College Observatory as one of the most important centers of astronomical research in the United States. George Bond was born in Massachusetts, and earned his B.A. degree from Harvard University in 1845. He then started work as assistant astronomer at the Harvard College Observatory. He demonstrated photographic astronomy’s use in mapping the sky and in measuring the comparative brightness and exact location of heavenly objects. He also used photography to study the moon’s surface and was the first person to photograph a dual star, Bond discovered Hyperion, the eighth satellite of Saturn, and Saturn’s or C ring, the dim ring that is closer to Saturn than the planet’s two brighter rings.
  (1846-1919), Pickering, Edward Charles American astronomer and physicist, who devised the meridian photometer with which he made more than 1,400,000 measurements of the magnitudes of stars. Pickering was born in Boston and educated at Harvard College (now Harvard University).
  (1855-1916), Lowell, Percival American astronomer, who made important records of the planets. He is best known for his belief that there are canals on the surface of Mars and that these canals provide proof of intelligent life there. Born in Boston, Massachusetts, and educated at Harvard University.
  (1862-1938), Campbell, William Wallace American astronomer, who pioneered in the use of spectroscopy to study the motions of stars. Born in Hancock County, Ohio, Campbell was educated at the University of Michigan. His Stellar Motions (1913) and catalog of nearly 1000 stellar velocities became the classic works in the field. Through his studies of planetary atmospheres, Campbell was also one of the first to declare (1894) Mars unsuitable to life as known on earth.
  (1863-1941), Cannon, Annie Jump American astronomer, born in Dover, Delaware, and educated at Wellesley and Radcliffe colleges. She was an assistant at the Harvard College Observatory from 1897 until 1911, when she was appointed curator of astronomical photographs. She was responsible for the photographic discovery of 5 novas and about 300 variable stars. She is best known for compiling a bibliography of about 200,000 references to variable stars and for completing a catalog of more than 350,000 stellar spectra; the catalog is still accepted as an international standard.
  (1889-1953), Hubble, Edwin Powell American astronomer who made important contributions to the study of galaxies, the expansion of the universe, and the size of the universe. Hubble was the first to discover that fuzzy patches of light in the sky called spiral nebula were actually galaxies like the earth’s galaxy, the Milky Way. Hubble also found the first evidence for the expansion of the universe, and his work led to a much better understanding of the universe’s size. Hubble was born in Marshfield, Missouri. He attended high school in Chicago, Illinois, and received his bachelor’s degree in mathematics and astronomy in 1910.
  (1893-1960), Baade (Wilhelm Heinrich) Walter German born U.S. astronomer, educated at the University of Göttingen, whose studies of stars in the Andromedagalaxy led him, in the 1950's, to double the common estimate of the size and age of the universe. Begun at Mount Wilson Observatory in 1931, these studies established two major types of stars: the younger, hotter, Population I type and the older, cooler, Population II.
  (1900-79), Payne-Gaposchkin, Cecilia Helena English-born American astrophysicist. Known for her study of variable stars, she was also the first astronomer to measure by means of spectral analysis the relative abundances of chemical elements in a star. She was the first to show that more than 60 percent of the known galactic novas in the Milky Way are concentrated in the quadrant containing the galactic center.
  (1905-73), Kuiper, Gerard Peter Dutch-born American astronomer, who is noted for his contributions to knowledge of the solar system and for his important role in connection with the United States space program. Kuiper was born in Harencarspel, the Netherlands.
  (1905-1993), Hogg, Helen Battles Sawyer American astronomer who spent her career in Canada locating and cataloging variable stars. Variable stars change brightness in regular intervals and the length of the cycle of one type of variable star depends on its brightness, so astronomers use them to calculate distances to stars and to determine the structure and size of galaxies. Hogg focused on variable stars in globular clusters, very old, extremely large, and dense groupings of stars found in the outer halo of the Milky Way galaxy.
  (1920-), Gold, Thomas Austrian-American astronomer, born in Vienna and educated at the University of Cambridge. He is best known as the developer-with Austrian-British mathematician Hermann Bondi and British astronomer Fred Hoyle-of the steady-state theory of the universe. The theory, proposed in 1948, holds that the universe is homogeneous and that matter is continuously being created as the universe expands.
  (1926-1993), Henize, Karl Gordon American astronaut and astronomer. Henize was one of a group of scientists selected by NASA for flights to the moon on later Apollo missions. From 1956 to 1959 he was a senior astronomer at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, where he worked on Project Moonwatch, an effort to track earth-orbiting satellites by telescope. Henize was selected by NASA in 1967 as a scientist-astronaut candidate for Apollo missions. After Skylab, Henize began working on designing experiments using telescopes aboard the space shuttle.
  (1934-1996), Sagan, Carl Edward American astronomer who popularized science and tried to make it more accessible to the public. Sagan’s research spanned many areas of astronomy, cosmology, and the philosophy of science, but he was especially interested in the origin of life on the earth and in the possibility of life elsewhere in the universe. Sagan was born in New York City. In the early 1960s Sagan did his first major research on the planetary surface and atmosphere of the planet Venus. At the time, many scientists believed that the surface of Venus might have moderate temperatures that humans could endure. Measurements of radiation from Venus seemed to show that even Venus’s dark side was nearly 300° C (nearly 600° F).

  ### By: Luke and Andrew

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