1.
Henry Draper
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Henry Draper was an American doctor and amateur astronomer. He is best known today as a pioneer of astrophotography, Henry Drapers father, John William Draper, was an accomplished doctor, chemist, botanist, and professor at New York University, he was also the first to photograph the moon through a telescope. Drapers mother was Antonia Coetana de Paiva Pereira Gardner, daughter of the physician to the Emperor of Brazil. His niece, Antonia Maury was also an astronomer and he graduated from New York University School of Medicine, at the age of 20, in 1857. He worked first as a physician at Bellevue Hospital, and later as both a professor and dean of medicine at New York University, in 1867 he married Mary Anna Palmer, a wealthy socialite who collaborated with him in his astronomy work. Draper was one of the pioneers of the use of astrophotography, in 1872, he took a stellar spectrum that showed absorption lines, others, such as Joseph Fraunhofer, Lewis Morris Rutherfurd and Angelo Secchi, preceded him in that ambition. He resigned his chair in the department in 1873, to allow for more time for original research. He directed an expedition to photograph the 1874 transit of Venus, using his 11 inch Clark Brothers photographic refractor he took a 50-minute exposure. He photographed the spectrum of Jupiter in 1880 and this historical Henry Draper telescope is now at the Toruń Centre for Astronomy at Piwnice, Poland. The small crater Draper on the Moon is named in his honor, the Changes of Blood-Cells in the Spleen, thesis,1858. A Text-Book on Chemistry,1866 revision of his fathers 1846 text, delusions of Medicine, Charms, talismans, amulets, astrology, and mesmerism,1873. The Discovery of Oxygen in the Sun by Photography,1877, the First Photograph of a Nebula. National Academy of Sciences Biographical Memoir
2.
Astronomy
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Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics, physics, and chemistry, in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, moons, stars, galaxies, and comets, while the phenomena include supernovae explosions, gamma ray bursts, more generally, all astronomical phenomena that originate outside Earths atmosphere are within the purview of astronomy. A related but distinct subject, physical cosmology, is concerned with the study of the Universe as a whole, Astronomy is the oldest of the natural sciences. The early civilizations in recorded history, such as the Babylonians, Greeks, Indians, Egyptians, Nubians, Iranians, Chinese, during the 20th century, the field of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects, theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the results and observations being used to confirm theoretical results. Astronomy is one of the few sciences where amateurs can play an active role, especially in the discovery. Amateur astronomers have made and contributed to many important astronomical discoveries, Astronomy means law of the stars. Astronomy should not be confused with astrology, the system which claims that human affairs are correlated with the positions of celestial objects. Although the two share a common origin, they are now entirely distinct. Generally, either the term astronomy or astrophysics may be used to refer to this subject, however, since most modern astronomical research deals with subjects related to physics, modern astronomy could actually be called astrophysics. Few fields, such as astrometry, are purely astronomy rather than also astrophysics, some titles of the leading scientific journals in this field includeThe Astronomical Journal, The Astrophysical Journal and Astronomy and Astrophysics. In early times, astronomy only comprised the observation and predictions of the motions of objects visible to the naked eye, in some locations, early cultures assembled massive artifacts that possibly had some astronomical purpose. Before tools such as the telescope were invented, early study of the stars was conducted using the naked eye, most of early astronomy actually consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, and the nature of the Sun, Moon, the Earth was believed to be the center of the Universe with the Sun, the Moon and the stars rotating around it. This is known as the model of the Universe, or the Ptolemaic system. The Babylonians discovered that lunar eclipses recurred in a cycle known as a saros
3.
Star catalogue
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A star catalogue or star catalog, is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers, there are a great many different star catalogues which have been produced for different purposes over the years, and this article covers only some of the more frequently quoted ones. Star catalogues were compiled by many different ancient peoples, including the Babylonians, Greeks, Chinese, Persians, most modern catalogues are available in electronic format and can be freely downloaded from space agencies data center. Completeness and accuracy is described by the weakest apparent magnitude V, from their existing records, it is known that the ancient Egyptians recorded the names of only a few identifiable constellations and a list of thirty-six decans that were used as a star clock. They are better known by their Assyrian-era name Three Stars Each and these star catalogues, written on clay tablets, listed thirty-six stars, twelve for Anu along the celestial equator, twelve for Ea south of that, and twelve for Enlil to the north. In Ancient Greece, the astronomer and mathematician Eudoxus laid down a set of the classical constellations around 370 BC. His catalogue Phaenomena, rewritten by Aratus of Soli between 275 and 250 BC as a poem, became one of the most consulted astronomical texts in antiquity. It contains descriptions of the positions of the stars, the shapes of the constellations, approximately in the 3rd century BC, the Greek astronomers Timocharis of Alexandria and Aristillus created another star catalogue. Hipparchus completed his star catalogue in 129 BC, which he compared to Timocharis and this led him to determine the first value of the precession of the equinoxes. In the 2nd century, Ptolemy of Roman Egypt published a star catalogue as part of his Almagest, ptolemys catalogue was based almost entirely on an earlier one by Hipparchus. It remained the star catalogue in the Western and Arab worlds for over eight centuries. The earliest known inscriptions for Chinese star names were written on oracle bones, sources dating from the Zhou Dynasty which provide star names include the Zuo Zhuan, the Shi Jing, and the Canon of Yao in the Book of Documents. The Lüshi Chunqiu written by the Qin statesman Lü Buwei provides most of the names for the twenty-eight mansions, an earlier lacquerware chest found in the Tomb of Marquis Yi of Zeng contains a complete list of the names of the twenty-eight mansions. Star catalogues are traditionally attributed to Shi Shen and Gan De, the Shi Shen astronomy is attributed to Shi Shen, and the Astronomic star observation to Gan De. It was not until the Han Dynasty that astronomers started to observe and record names for all the stars that were apparent in the night sky, not just those around the ecliptic. A star catalogue is featured in one of the chapters of the late 2nd-century-BC history work Records of the Grand Historian by Sima Qian and contains the schools of Shi Shen and Gan Des work. For his Spiritual Constitution of the Universe of 120 AD, the astronomer Zhang Heng compiled a star catalogue comprising 124 constellations, Chinese constellation names were later adopted by the Koreans and Japanese. A large number of star catalogues were published by Muslim astronomers in the medieval Islamic world and these were mainly Zij treatises, including Arzachels Tables of Toledo, the Maragheh observatorys Zij-i Ilkhani and Ulugh Begs Zij-i-Sultani
4.
Spectroscopy
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Spectroscopy /spɛkˈtrɒskəpi/ is the study of the interaction between matter and electromagnetic radiation. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, later the concept was expanded greatly to include any interaction with radiative energy as a function of its wavelength or frequency. Spectroscopic data is represented by an emission spectrum, a plot of the response of interest as a function of wavelength or frequency. Spectroscopy and spectrography are terms used to refer to the measurement of radiation intensity as a function of wavelength and are used to describe experimental spectroscopic methods. Spectral measurement devices are referred to as spectrometers, spectrophotometers, spectrographs or spectral analyzers, daily observations of color can be related to spectroscopy. Neon lighting is an application of atomic spectroscopy. Neon and other noble gases have characteristic emission frequencies, neon lamps use collision of electrons with the gas to excite these emissions. Inks, dyes and paints include chemical compounds selected for their characteristics in order to generate specific colors. A commonly encountered molecular spectrum is that of nitrogen dioxide, gaseous nitrogen dioxide has a characteristic red absorption feature, and this gives air polluted with nitrogen dioxide a reddish-brown color. Rayleigh scattering is a spectroscopic scattering phenomenon that accounts for the color of the sky, Spectroscopy is used in physical and analytical chemistry because atoms and molecules have unique spectra. As a result, these spectra can be used to detect, identify and quantify information about the atoms, Spectroscopy is also used in astronomy and remote sensing on earth. The measured spectra are used to determine the composition and physical properties of astronomical objects. One of the concepts in spectroscopy is a resonance and its corresponding resonant frequency. Resonances were first characterized in mechanical systems such as pendulums, mechanical systems that vibrate or oscillate will experience large amplitude oscillations when they are driven at their resonant frequency. A plot of amplitude vs. excitation frequency will have a peak centered at the resonance frequency and this plot is one type of spectrum, with the peak often referred to as a spectral line, and most spectral lines have a similar appearance. In quantum mechanical systems, the resonance is a coupling of two quantum mechanical stationary states of one system, such as an atom, via an oscillatory source of energy such as a photon. The coupling of the two states is strongest when the energy of the matches the energy difference between the two states. The energy of a photon is related to its frequency by E = h ν where h is Plancks constant, spectra of atoms and molecules often consist of a series of spectral lines, each one representing a resonance between two different quantum states
5.
Stellar classification
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In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with absorption lines, each line indicates an ion of a certain chemical element, with the line strength indicating the abundance of that ion. The relative abundance of the different ions varies with the temperature of the photosphere, the spectral class of a star is a short code summarizing the ionization state, giving an objective measure of the photospheres temperature and density. Most stars are classified under the Morgan–Keenan system using the letters O, B, A, F, G, K, and M. Each letter class is subdivided using a numeric digit with 0 being hottest and 9 being coolest. The sequence has been expanded with classes for other stars and star-like objects that do not fit in the system, such as class D for white dwarfs. In the MK system, a luminosity class is added to the class using Roman numerals. This is based on the width of absorption lines in the stars spectrum. The full spectral class for the Sun is then G2V, indicating a main-sequence star with a temperature around 5,800 K, the conventional color description takes into account only the peak of the stellar spectrum. This means that the assignment of colors of the spectrum can be misleading. There are no green, indigo, or violet stars, likewise, the brown dwarfs do not literally appear brown. The modern classification system is known as the Morgan–Keenan classification, each star is assigned a spectral class from the older Harvard spectral classification and a luminosity class using Roman numerals as explained below, forming the stars spectral type. The spectral classes O through M, as well as more specialized classes discussed later, are subdivided by Arabic numerals. For example, A0 denotes the hottest stars in the A class, fractional numbers are allowed, for example, the star Mu Normae is classified as O9.7. The Sun is classified as G2, the conventional color descriptions are traditional in astronomy, and represent colors relative to the mean color of an A-class star, which is considered to be white. The apparent color descriptions are what the observer would see if trying to describe the stars under a dark sky without aid to the eye, or with binoculars. However, most stars in the sky, except the brightest ones, red supergiants are cooler and redder than dwarfs of the same spectral type, and stars with particular spectral features such as carbon stars may be far redder than any black body. O-, B-, and A-type stars are called early type
6.
Spectrum
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A spectrum is a condition that is not limited to a specific set of values but can vary, without steps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism, as scientific understanding of light advanced, it came to apply to the entire electromagnetic spectrum. Spectrum has since been applied by analogy to topics outside of optics, thus, one might talk about the spectrum of political opinion, or the spectrum of activity of a drug, or the autism spectrum. In these uses, values within a spectrum may not be associated with precisely quantifiable numbers or definitions, such uses imply a broad range of conditions or behaviors grouped together and studied under a single title for ease of discussion. Nonscientific uses of the spectrum are sometimes misleading. For instance, a single left–right spectrum of opinion does not capture the full range of peoples political beliefs. Political scientists use a variety of biaxial and multiaxial systems to accurately characterize political opinion. In most modern usages of spectrum there is a theme between the extremes at either end. This was not always true in older usage, in Latin spectrum means image or apparition, including the meaning spectre. Spectral evidence is testimony about what was done by spectres of persons not present physically and it was used to convict a number of persons of witchcraft at Salem, Massachusetts in the late 17th century. The word spectrum was used to designate a ghostly optical afterimage by Goethe in his Theory of Colors and Schopenhauer in On Vision. The prefix spectro- is used to form words relating to spectra, for example, a spectrometer is a device used to record spectra and spectroscopy is the use of a spectrometer for chemical analysis. In the 17th century the word spectrum was introduced into optics by Isaac Newton, soon the term referred to a plot of light intensity or power as a function of frequency or wavelength, also known as a spectral density plot. The term spectrum was expanded to apply to other waves, such as sound waves that could also be measured as a function of frequency, frequency spectrum and power spectrum of a signal. The term now applies to any signal that can be measured or decomposed along a variable such as energy in electron spectroscopy or mass to charge ratio in mass spectrometry. Spectrum is also used to refer to a representation of the signal as a function of the dependent variable. Devices used to measure an electromagnetic spectrum are called spectrograph or spectrometer, the visible spectrum is the part of the electromagnetic spectrum that can be seen by the human eye. The wavelength of light ranges from 390 to 700 nm
7.
Spectral line
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Spectral lines are often used to identify atoms and molecules from their characteristic spectral lines. Spectral lines are the result of interaction between a system and a single photon. When a photon has about the amount of energy to allow a change in the energy state of the system. A spectral line may be observed either as a line or an absorption line. Which type of line is observed depends on the type of material, an absorption line is produced when photons from a hot, broad spectrum source pass through a cold material. The intensity of light, over a frequency range, is reduced due to absorption by the material. By contrast, a bright, emission line is produced when photons from a hot material are detected in the presence of a spectrum from a cold source. The intensity of light, over a frequency range, is increased due to emission by the material. Spectral lines are highly atom-specific, and can be used to identify the composition of any medium capable of letting light pass through it. Several elements were discovered by means, such as helium, thallium. Mechanisms other than atom-photon interaction can produce spectral lines, depending on the exact physical interaction, the frequency of the involved photons will vary widely, and lines can be observed across the electromagnetic spectrum, from radio waves to gamma rays. In other cases the lines are designated according to the level of ionization by adding a Roman numeral to the designation of the chemical element, so that Ca+ also has the designation Ca II. Neutral atoms are denoted with the roman number I, singly ionized atoms with II, more detailed designations usually include the line wavelength and may include a multiplet number or band designation. Many spectral lines of hydrogen also have designations within their respective series. A spectral line extends over a range of frequencies, not a single frequency, in addition, its center may be shifted from its nominal central wavelength. There are several reasons for this broadening and shift and these reasons may be divided into two general categories – broadening due to local conditions and broadening due to extended conditions. Broadening due to conditions is due to effects which hold in a small region around the emitting element. Broadening due to extended conditions may result from changes to the distribution of the radiation as it traverses its path to the observer
8.
Vega
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It is relatively close at only 25 light-years from the Sun, and, together with Arcturus and Sirius, one of the most luminous stars in the Suns neighborhood. Vega has been studied by astronomers, leading it to be termed “arguably the next most important star in the sky after the Sun. ”Vega was the northern pole star around 12,000 BC. Vega was the first star other than the Sun to be photographed and it was one of the first stars whose distance was estimated through parallax measurements. Vega has served as the baseline for calibrating the photometric brightness scale, Vega has an unusually low abundance of the elements with a higher atomic number than that of helium. Vega is also a star that varies slightly in brightness. It is rotating rapidly with a velocity of 274 km/s at the equator and this is causing the equator to bulge outward because of centrifugal effects, and, as a result, there is a variation of temperature across the stars photosphere that reaches a maximum at the poles. From Earth, Vega is being observed from the direction of one of these poles, based on an observed excess emission of infrared radiation, Vega appears to have a circumstellar disk of dust. This dust is likely to be the result of collisions between objects in a debris disk, which is analogous to the Kuiper belt in the Solar System. Stars that display an infrared excess because of dust emission are termed Vega-like stars, α Lyrae is the stars Bayer designation. The traditional name Vega comes from a transliteration of the Arabic word wāqi‘ meaning falling or landing, via the phrase an-nasr al-wāqi‘. In 2016, the International Astronomical Union organized a Working Group on Star Names to catalog, the WGSNs first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included Vega for this star. It is now so entered in the IAU Catalog of Star Names, astrophotography, the photography of celestial objects, began in 1840 when John William Draper took an image of the Moon using the daguerreotype process. On July 17,1850, Vega became the first star to be photographed, when it was imaged by William Bond and John Adams Whipple at the Harvard College Observatory, also with a daguerreotype. Henry Draper took the first photograph of a spectrum in August 1872 when he took an image of Vega. Similar lines had already identified in the spectrum of the Sun. In 1879, William Huggins used photographs of the spectra of Vega and these were later identified as lines from the Hydrogen Balmer series. Since 1943, the spectrum of this star has served as one of the anchor points by which other stars are classified. The distance to Vega can be determined by measuring its parallax shift against the stars as the Earth orbits the Sun
9.
Edward Charles Pickering
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Edward Charles Pickering was an American astronomer and physicist as well as the older brother of William Henry Pickering. Along with Carl Vogel, Pickering discovered the first spectroscopic binary stars and he wrote Elements of Physical Manipulations. Pickering attended Boston Latin School, and received his B. S. from Harvard in 1865, soon after graduating from Harvard, Pickering taught physics at the Massachusetts Institute of Technology. Later, he served as director of Harvard College Observatory from 1877 to his death in 1919, at Harvard, he recruited over 80 women to work for him, including Annie Jump Cannon, Henrietta Swan Leavitt, and Antonia Maury. These women, the Harvard Computers, made important discoveries at HCO. Leavitts discovery of the period-luminosity relationship for Cepheids, published by Pickering, in 1876 he co-founded the Appalachian Mountain Club. In 1882, Pickering developed a method to photograph the spectra of multiple stars simultaneously by putting a large prism in front of the photographic plate. Pickering is credited for making the Harvard College Observatory known and respected around the world, the Allegheny Observatory In Its Relation To Astronomy
10.
Harvard College Observatory
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The Harvard College Observatory is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, USA, and was founded in 1839, with the Smithsonian Astrophysical Observatory, it forms part of the Harvard–Smithsonian Center for Astrophysics. HCO houses a collection of approximately 500,000 astronomical plates taken between the mid-1880s and 1989 and this 100-year coverage is a unique resource for studying temporal variations in the universe. The Digital Access to a Sky Century @ Harvard project is digitally scanning and archiving these photographic plates, in 1839, the Harvard Corporation voted to appoint William Cranch Bond, a prominent Boston clockmaker, as Astronomical Observer to the University. This marked the founding of the Harvard College Observatory, hCOs first telescope, the 15-inch Great Refractor, was installed in 1847. That telescope was the largest in the United States from installation until 1867, on the night of July 16–17,1850, Whipple and Bond made the first daguerreotype of a star. Cannon and Leavitt were hired initially as computers to perform calculations and examine stellar photographs, from 1898 to 1926, a series of Bulletins were issued containing many of the major discoveries of the period. These were then replaced by Announcement Cards which continued to be issued until 1952, in 1908, the observatory published the Harvard Revised Photometry Catalogue, which gave rise to the HR star catalogue, now maintained by the Yale University Observatory as the Bright Star Catalogue. Field 1971–1972 Harvard Computers Sears Tower – Harvard Observatory The Minor Planet Center credits many asteroid discoveries to Harvard Observatory, see List of largest optical refracting telescopes, for other great refractors Dava Sobel. The Glass Universe, How the Ladies of the Harvard Observatory Took the Measure of the Stars, HCO home page Harvard-Smithsonian Center for Astrophysics Harvard College Observatory Bulletins Harvard College Announcement Cards
11.
Williamina Fleming
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Williamina Paton Stevens Fleming was a Scottish-born and American astronomer. During her career, she helped develop a common system for stars and cataloged thousands of stars. Among several career achievements that advanced astronomy Fleming is noted for her discovery of the Horsehead Nebula in 1888, williamina Stevens was born on May 15,1857, to Mary and Robert Stevens, he a carver and gilder of Dundee, Scotland. There, in 1877, she married James Orr Fleming, an accountant and she worked as a teacher a short time before the couple emigrated to Boston, Massachusetts, USA, when she was 21. After she and her child were abandoned by James Fleming, she worked as a maid in the home of Professor Edward Charles Pickering, who was director of the Harvard College Observatory. The story was told that Pickering was often frustrated with the performance of the computers at the observatory and, reportedly, would complain loudly, My Scottish maid could do better. In 1881 Pickering hired Fleming to join the HCO and taught her how to analyze stellar spectra, soon she devised a system for classifying stars according to the relative amount of hydrogen observed in their spectra. Later, Annie Jump Cannon developed a classification system based upon the surface temperature of stars. Fleming contributed to the cataloging of stars that later were published as the Henry Draper Catalogue, in nine years effort she cataloged more than 10,000 stars. During her career she discovered 59 gaseous nebulae, over 310 variable stars, in 1907 she published a list of 222 variable stars she had discovered. Subsequent professional publications neglected to credit to Fleming and W. H. C. In 1886 Fleming was placed in charge of the dozens of women hired to compute mathematical classifications, soon after she was appointed honorary fellow in astronomy of Wellesley College. Shortly before her death the Astronomical Society of Mexico awarded her the Guadalupe Almendaro medal for her discovery of new stars and she published A Photographic Study of Variable Stars. She published her discovery of white dwarfs, also she published Spectra and Photographic Magnitudes of Stars in Standard Regions. She died in Boston on May 21,1911, the lunar crater Fleming was jointly named after her and Alexander Fleming. In 1906, she was made a member of the Royal Astronomical Society of London. Birth and Marriage details from Scotlands People website http, //www. scotlandspeople. gov
12.
Antonia Maury
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Antonia Maury was an American astronomer who published an important early catalog of stellar spectra. Antonia Coetana de Paiva Pereira Maury was born in Cold Spring, maurys father was the Reverend Mytton Maury, a direct descendant of the Reverend James Maury and one of the sons of Sarah Mytton Maury. Maurys mother was Virginia Draper, a daughter of Antonia Coetana de Paiva Pereira Gardner, Maury was also the granddaughter of John William Draper and a niece of Henry Draper, both pioneering astronomers. As such, young Antonia and her two siblings were exposed to science at an early age. Her younger sister, Carlotta Maury, went on to become a geologist, stratigrapher, Antonia Maury attended Vassar College, graduating in 1887 with honors in physics, astronomy, and philosophy. There, she studied under the tutelage of renowned astronomer Maria Mitchell, after completing her undergraduate work, Maury went to work at the Harvard College Observatory as one of the so-called Harvard Computers, highly skilled women who processed astronomical data. In this capacity, Maury observed stellar spectra and published an important catalogue of classifications in 1897, edward Charles Pickering, the observatorys director, disagreed with Maury’s system of classification and explanation of differing line widths. In response to negative reaction to her work, she decided to leave the observatory. However, Danish astronomer Ejnar Hertzsprung realized the value of her classifications and used them in his system of identifying giant, in 1908, Maury returned to Harvard College Observatory where she remained for many years. Her most famous work there was the analysis of the binary star Beta Lyrae. After retirement, Maury pursued interests in nature and conservation and she enjoyed bird-watching, and she fought to save western Sequoia trees from being felled during wartime. Maury died on January 8,1952, in Dobbs Ferry, in 1943, Antonia Maury was awarded the Annie Jump Cannon Award in Astronomy by the American Astronomical Society. The lunar crater Maury and a number of smaller craters are co-named for Antonia Maury. They were originally named for her cousin, Commander Matthew Fontaine Maury, United States Navy and are, perhaps, Maury Family Tree by Sue C. West-Teague Antonia Maury Vassar alumnae magazine, v.37, March 1952 Maury, Antonia Coetana De Paiva Pereira, P. 240-241 by Martha J. Bailey Gingerich, Owen. Maury, Antonia Caetana de Paiva Pereira, the Remarkable Lives of 100 Women Healers and Scientists. Sky and Telescope, v.11, March 1952,106, Maury, Antonia Caetana De Paiva Pereira. Notable American Women, the Modern Period, edited by Barbara Sicherman, Carold Hurd Green, with Ilene Kantrov, Harriette Walker
13.
Arequipa
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Arequipa is the capital and largest city of the Arequipa Region and the seat of the Constitutional Court of Peru. Its industrial activity includes manufactured goods and camelid wool products for export, the city has close trade ties with Chile, Bolivia and Brazil. The city was founded on August 15,1540, by Garcí Manuel de Carbajal as Villa Hermosa de Nuestra Señora de la Asunción, during the Colonial period, Arequipa became highly important for its economic prosperity and for its loyalty to the Spanish Crown. After Peru gained its independence from Spain in 1821, Arequipa acquired greater political significance, the historic center of Arequipa spans an area of 332 hectares and is a UNESCO World Heritage Site. Its historic heritage, natural scenery and cultural sites make the city a major tourist destination and its religious, colonial, and republican architectural styles blend European and native characteristics into a unique style called Escuela Arequipeña. A local tradition states that Inca Mayta Capac received a petition from his subjects to reach the valley of the River Chili and they asked him for permission to stay in the region as they were impressed by the beauty of the landscape and the mild climate. However, another tale states that when the first Europeans arrived to the valley, they pointed at the ground. The local chief, not understanding the question, assumed they were asking for a permission to sit down and gave a positive answer, which sounded like Arequipa. Another possible origin of the name comes from the Aymara language phrase qhipaya ari or Ari qipa. The early inhabitants of the Arequipa City area were people who relied on activities such as hunting, fishing and gathering for survival. Later, pre-Inca cultures domesticated llamas and became sedentary with the development of agriculture, during this time, major irrigation channels were built within the valley of the Chili river, which allowed the development of agriculture by means of terraces built on both sides of the valley. The Yarabaya and Chimbe tribes settled in the current location. Lands were then distributed among three families who founded the towns of Yanahuara, Cayma, Tiabaya, Socabaya, Characato and others. At the time of its foundation, Arequipa had already a city council, because the foundation of the town occurred in part as a relocation of Villa Hermosa de Camana, the name was partially conserved as Villa Hermosa de Arequipa. Charles V of Germany and I of Spain gave the town a status of city by Royal Decree on 22 September 1541, the relocation efforts were led by Garci Manuel de Carbajal, who was selected as the political authority for the foundation of the new town. Among the first public works carried out in the city are the Main Church, the City Hall, the bridge on the Chili River and the monastery of Nuestra Señora de Gracia. Since its Spanish founding and over three centuries, the population of the city was mostly of Spanish origin, which represented a strong following of Spain. One aspect that distinguished Arequipa from the rest of the country was the explicit and public commitment of the city to the Spanish Crown
14.
Peru
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Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the west by the Pacific Ocean. Peruvian territory was home to ancient cultures spanning from the Norte Chico civilization in Caral, one of the oldest in the world, to the Inca Empire, the largest state in Pre-Columbian America. The Spanish Empire conquered the region in the 16th century and established a Viceroyalty with its capital in Lima, ideas of political autonomy later spread throughout Spanish America and Peru gained its independence, which was formally proclaimed in 1821. After the battle of Ayacucho, three years after proclamation, Peru ensured its independence, subsequently, the country has undergone changes in government from oligarchic to democratic systems. Peru has gone through periods of political unrest and internal conflict as well as periods of stability, Peru is a representative democratic republic divided into 25 regions. It is a country with a high Human Development Index score. Its main economic activities include mining, manufacturing, agriculture and fishing, the Peruvian population, estimated at 31.2 million in 2015, is multiethnic, including Amerindians, Europeans, Africans and Asians. The main spoken language is Spanish, although a significant number of Peruvians speak Quechua or other native languages and this mixture of cultural traditions has resulted in a wide diversity of expressions in fields such as art, cuisine, literature, and music. The name of the country may be derived from Birú, the name of a ruler who lived near the Bay of San Miguel, Panama. When his possessions were visited by Spanish explorers in 1522, they were the southernmost part of the New World yet known to Europeans, thus, when Francisco Pizarro explored the regions farther south, they came to be designated Birú or Perú. An alternative history is provided by the contemporary writer Inca Garcilasco de la Vega, son of an Inca princess, the Spanish Crown gave the name legal status with the 1529 Capitulación de Toledo, which designated the newly encountered Inca Empire as the province of Peru. Under Spanish rule, the country adopted the denomination Viceroyalty of Peru, the earliest evidences of human presence in Peruvian territory have been dated to approximately 9,000 BC. Andean societies were based on agriculture, using such as irrigation and terracing, camelid husbandry. Organization relied on reciprocity and redistribution because these societies had no notion of market or money, the oldest known complex society in Peru, the Norte Chico civilization, flourished along the coast of the Pacific Ocean between 3,000 and 1,800 BC. These early developments were followed by archaeological cultures that developed mostly around the coastal, the Cupisnique culture which flourished from around 1000 to 200 BC along what is now Perus Pacific Coast was an example of early pre-Incan culture. The Chavín culture that developed from 1500 to 300 BC was probably more of a religious than a political phenomenon, on the coast, these included the civilizations of the Paracas, Nazca, Wari, and the more outstanding Chimu and Mochica. Their capital was at Chan Chan outside of modern-day Trujillo, in the 15th century, the Incas emerged as a powerful state which, in the span of a century, formed the largest empire in pre-Columbian America with their capital in Cusco
15.
Southern Hemisphere
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The Southern Hemisphere is the half sphere of Earth which is south of the equator. It contains all or parts of five continents, four oceans and its surface is 80. 9% water, compared with 60. 7% water in the case of the Northern Hemisphere, and it contains 32. 7% of Earths land. Due to the tilt of Earths rotation relative to the Sun, September 22 or 23 is the vernal equinox and March 20 or 21 is the autumnal equinox. The South Pole is in the middle of the southern hemispherical region, Southern Hemisphere climates tend to be slightly milder than those at similar latitudes in the Northern Hemisphere, except in the Antarctic which is colder than the Arctic. This is because the Southern Hemisphere has significantly more ocean and much land, water heats up. In the Southern Hemisphere the sun passes from east to west through the north, sun-cast shadows turn anticlockwise throughout the day and sundials have the hours increasing in the anticlockwise direction. Cyclones and tropical storms spin clockwise in the Southern Hemisphere due to the Coriolis effect, the southern temperate zone, a subsection of the Southern Hemisphere, is nearly all oceanic. Forests in the Southern Hemisphere have special features which set apart from those in the Northern Hemisphere. Both Chile and Australia share, for example, unique species or Nothofagus. The eucalyptus is native to Australia but is now planted in Southern Africa and Latin America for pulp production and, increasingly. Approximately 800,000,000 humans live in the Southern Hemisphere and this is due to the fact that there is significantly less land in the Southern Hemisphere than in the Northern Hemisphere. Africa Antarctica Asia Australia South America Zealandia Media related to Southern Hemisphere at Wikimedia Commons
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Annie Jump Cannon
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Annie Jump Cannon was an American astronomer whose cataloging work was instrumental in the development of contemporary stellar classification. Pickering, she is credited with the creation of the Harvard Classification Scheme and she was nearly deaf throughout her career. Annie Jump Cannon was born on December 11,1863, in Dover and she was the eldest of three daughters born to Wilson Cannon, a Delaware shipbuilder and state senator, and his second wife, Mary Jump. Cannon took her mothers advice and pursued her love of astronomy, Cannon suffered hearing loss sometime during her childhood or early adult years. Sources vary on the frame and actual cause, although it is sometimes attributed to scarlet fever. Some people claim Cannons hearing loss made it difficult for her to socialize and she never married and did not have children. At Wilmington Conference Academy, Cannon was a student, particularly in mathematics. In 1880, Cannon was sent to Wellesley College in Massachusetts, one of the top schools for women in the US. Cannon studied under Sarah Frances Whiting, one of the few women physicists in the United States at the time and she graduated with a degree in physics in 1884 and returned home to Delaware for a decade. During these years, Cannon developed her skills in the new art of photography, in 1892 she traveled through Europe taking photographs with her Blair box camera. Soon afterward, Cannon was stricken with scarlet fever that rendered her nearly deaf and this hearing loss made it difficult for Cannon to socialize. As a result, she immersed herself in her work and she never married nor had children. In 1894, Cannons mother died and life at home grew more difficult and she wrote to her former instructor at Wellesley, professor Sarah Frances Whiting, to see if there was a job opening. Whiting hired her as a physics teacher at the college. This opportunity allowed Cannon to take courses at the college in physics. Whiting also inspired Cannon to learn about spectroscopy, in order to gain access to a better telescope, Cannon enrolled at Radcliffe College as a special student, continuing her studies of astronomy. Radcliffe was set up near Harvard College for Harvard professors to repeat their lectures to the young Radcliffe women and this relationship gave Cannon access to the Harvard College Observatory. Pickering hired her as his assistant at the Observatory, in 1907, Cannon finished her studies and received her masters from Wellesley College
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Carbon star
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There are also some dwarf and supergiant carbon stars, with the more common giant stars sometimes being called classical carbon stars to distinguish them. In most stars, the atmosphere is richer in oxygen than carbon, ordinary stars not exhibiting the characteristics of carbon stars but cool enough to form carbon monoxide are therefore called oxygen-rich stars. Carbon stars have quite distinctive spectral characteristics, and they were first recognized by their spectra by Angelo Secchi in the 1860s, by definition carbon stars have dominant spectral Swan bands from the molecule C2. Many other carbon compounds may be present at levels, such as CH, CN, C3. Carbon is formed in the core and circulated into its upper layers, in addition to carbon, S-process elements such as barium, technetium, and zirconium are formed in the shell flashes and are dredged up to the surface. When astronomers developed the classification of the carbon stars, they had considerable difficulty when trying to correlate the spectra to the stars effective temperatures. The trouble was all the atmospheric carbon hiding the absorption lines normally used as temperature indicators for the stars. Carbon stars also show a spectrum of molecular lines at millimeter wavelengths. In the carbon star IRC+10216 more than 50 different circumstellar molecules have been detected and this star is often used to search for new circumstellar molecules. Using this new Harvard classification, the N class was later enhanced by an R class for less deeply red stars sharing the characteristic carbon bands of the spectrum. Later correlation of this R to N scheme with conventional spectra, showed that the R-N sequence approximately run in parallel with c, instead a new dual number star class C was erected so to deal with temperature and carbon abundance. Such a spectrum measured for Y Canum Venaticorum, was determined to be C54, where 5 refers to temperature dependent features and this Morgan–Keenan C system classification replaced the older R-N classifications from 1960–1993. A new revised Morgan–Keenan classification was published in 1993 by Philip Keenan, defining the classes, C-N, C-R, later the classes C-J and C-Hd were added. This constitutes the established classification system used today, carbon stars can be explained by more than one astrophysical mechanism. Classical carbon stars are distinguished from non-classical ones on the grounds of mass and these fusion products have been brought to the stellar surface by episodes of convection after the carbon and other products were made. In this phase, the luminosity rises, and material from the interior of the star moves up. Since the luminosity rises, the star expands so that the helium fusion ceases, and the hydrogen shell burning restarts. The non-classical kinds of stars, belonging to the types C-J and C-H, are believed to be binary stars, where one star is observed to be a giant star
18.
Apparent magnitude
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The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth. The brighter an object appears, the lower its magnitude value, the Sun, at apparent magnitude of −27, is the brightest object in the sky. It is adjusted to the value it would have in the absence of the atmosphere, furthermore, the magnitude scale is logarithmic, a difference of one in magnitude corresponds to a change in brightness by a factor of 5√100, or about 2.512. The measurement of apparent magnitudes or brightnesses of celestial objects is known as photometry, apparent magnitudes are used to quantify the brightness of sources at ultraviolet, visible, and infrared wavelengths. An apparent magnitude is measured in a specific passband corresponding to some photometric system such as the UBV system. In standard astronomical notation, an apparent magnitude in the V filter band would be denoted either as mV or often simply as V, the scale used to indicate magnitude originates in the Hellenistic practice of dividing stars visible to the naked eye into six magnitudes. The brightest stars in the sky were said to be of first magnitude, whereas the faintest were of sixth magnitude. Each grade of magnitude was considered twice the brightness of the following grade and this rather crude scale for the brightness of stars was popularized by Ptolemy in his Almagest, and is generally believed to have originated with Hipparchus. This implies that a star of magnitude m is 2.512 times as bright as a star of magnitude m +1 and this figure, the fifth root of 100, became known as Pogsons Ratio. The zero point of Pogsons scale was defined by assigning Polaris a magnitude of exactly 2. However, with the advent of infrared astronomy it was revealed that Vegas radiation includes an Infrared excess presumably due to a disk consisting of dust at warm temperatures. At shorter wavelengths, there is negligible emission from dust at these temperatures, however, in order to properly extend the magnitude scale further into the infrared, this peculiarity of Vega should not affect the definition of the magnitude scale. Therefore, the scale was extrapolated to all wavelengths on the basis of the black body radiation curve for an ideal stellar surface at 11000 K uncontaminated by circumstellar radiation. On this basis the spectral irradiance for the zero magnitude point, with the modern magnitude systems, brightness over a very wide range is specified according to the logarithmic definition detailed below, using this zero reference. In practice such apparent magnitudes do not exceed 30, astronomers have developed other photometric zeropoint systems as alternatives to the Vega system. The AB magnitude zeropoint is defined such that an objects AB, the dimmer an object appears, the higher the numerical value given to its apparent magnitude, with a difference of 5 magnitudes corresponding to a brightness factor of exactly 100. Since an increase of 5 magnitudes corresponds to a decrease in brightness by a factor of exactly 100, each magnitude increase implies a decrease in brightness by the factor 5√100 ≈2.512. Inverting the above formula, a magnitude difference m1 − m2 = Δm implies a brightness factor of F2 F1 =100 Δ m 5 =100.4 Δ m ≈2.512 Δ m
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Right ascension
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Right ascension is the angular distance measured eastward along the celestial equator from the vernal equinox to the hour circle of the point in question. When combined with declination, these astronomical coordinates specify the direction of a point on the sphere in the equatorial coordinate system. Right ascension is the equivalent of terrestrial longitude. Both right ascension and longitude measure an angle from a direction on an equator. Right ascension is measured continuously in a circle from that equinox towards the east. Any units of measure could have been chosen for right ascension, but it is customarily measured in hours, minutes. Astronomers have chosen this unit to measure right ascension because they measure a stars location by timing its passage through the highest point in the sky as the Earth rotates. The highest point in the sky, called meridian, is the projection of a line onto the celestial sphere. A full circle, measured in units, contains 24 × 60 × 60 = 86 400s, or 24 × 60 = 1 440m. Because right ascensions are measured in hours, they can be used to time the positions of objects in the sky. For example, if a star with RA = 01h 30m 00s is on the meridian, sidereal hour angle, used in celestial navigation, is similar to right ascension, but increases westward rather than eastward. Usually measured in degrees, it is the complement of right ascension with respect to 24h and it is important not to confuse sidereal hour angle with the astronomical concept of hour angle, which measures angular distance of an object westward from the local meridian. The Earths axis rotates slowly westward about the poles of the ecliptic and this effect, known as precession, causes the coordinates of stationary celestial objects to change continuously, if rather slowly. Therefore, equatorial coordinates are inherently relative to the year of their observation, coordinates from different epochs must be mathematically rotated to match each other, or to match a standard epoch. The right ascension of Polaris is increasing quickly, the North Ecliptic Pole in Draco and the South Ecliptic Pole in Dorado are always at right ascension 18h and 6h respectively. The currently used standard epoch is J2000.0, which is January 1,2000 at 12,00 TT, the prefix J indicates that it is a Julian epoch. Prior to J2000.0, astronomers used the successive Besselian Epochs B1875.0, B1900.0, the concept of right ascension has been known at least as far back as Hipparchus who measured stars in equatorial coordinates in the 2nd century BC. But Hipparchus and his successors made their star catalogs in ecliptic coordinates, the easiest way to do that is to use an equatorial mount, which allows the telescope to be aligned with one of its two pivots parallel to the Earths axis
