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90-508: During his time at Lick, Mayall contributed to astronomical knowledge of nebulae , supernovae , spiral galaxy internal motions, the redshifts of galaxies, and the origin, age, and size of the Universe. He played a significant role in the planning and construction of Lick's 120-inch (3.0 m) reflector , which represented a major improvement over its earlier 36-inch (0.91 m) telescope. From 1960, Mayall spent 11 years as director of

180-540: A movie of the same name in 2016), depicts African-American women who served as human computers at NASA in support of the Friendship 7 , the first American crewed mission into Earth orbit. NACA had begun hiring black women as computers from 1940. One such computer was Dorothy Vaughan who began her work in 1943 with the Langley Research Center as a special hire to aid the war effort, and who came to supervise

270-417: A supernova remnant , a special diffuse nebula . Although much of the optical and X-ray emission from supernova remnants originates from ionized gas, a great amount of the radio emission is a form of non-thermal emission called synchrotron emission . This emission originates from high-velocity electrons oscillating within magnetic fields . Human computer The term " computer ", in use from

360-536: A type II supernova while conducting other research. Other research Mayall performed included the 20 year collaboration (formulated in 1935 by Hubble) with Milton Humason, to gather redshift values for all northern galaxies brighter than +13 visual magnitude . Mayall handled the brighter galaxies on the Crossley, while Humason tackled the fainter ones using the Mount Wilson 100-inch (2.5 m). This work resulted in

450-503: A brief return to Peoria, Illinois during 1918–1919). During this period, presumably during his high school years, Mayall's parents divorced. During his senior year , in the fall of 1923, Mayall was secretary of the school science club and set up a club visit to the Lick Observatory . His father permitted him to use his car, a Moline Knight , to transport the club members up the dirt and gravel winding mountain road leading to

540-433: A class of emission nebula associated with giant molecular clouds. These form as a molecular cloud collapses under its own weight, producing stars. Massive stars may form in the center, and their ultraviolet radiation ionizes the surrounding gas, making it visible at optical wavelengths . The region of ionized hydrogen surrounding the massive stars is known as an H II region while the shells of neutral hydrogen surrounding

630-520: A consultant to AURA, due to his experience in planning the Lick 120-inch (3.0 m) telescope. The board's president was Shane, who was representing the University of California, and he helped convince Mayall to accept the offer. As director, Mayall oversaw the building of the 4-meter (160 in) Kitt Peak reflector. It was still being built when he retired in 1971, and was completed in 1973, at which point it

720-837: A course of graduate level study followed by a career as a research scientist. After graduating in 1928, Mayall decided to remain at Berkeley, as it had the best astronomy graduate program of the day. However, he took a hiatus from pursuing his advanced degree and went to work as a human computer at the Mount Wilson Observatory from 1929 to 1931, where he assisted prominent astronomers including Edwin Hubble , Paul W. Merrill , and Milton L. Humason . This activity resulted in him co-authoring papers on Pluto 's mass and orbit with Seth Barnes Nicholson and others, shortly after Pluto's discovery Mayall returned to Berkeley in 1931 to pursue graduate studies. His thesis topic, suggested by Hubble,

810-421: A high degree of precision were needed for navigation and engineering. Approaches differed, but one was to break up the project into a form of piece work completed at home. The computers, often educated middle class women whom society deemed it unseemly to engage in the professions or go out to work, would receive and send back packets of calculations by post. The Royal Astronomical Society eventually gave space to

900-471: A larger reflector to replace the 36-inch (0.91 m) Crossley Reflector. They tried both private sources as well as trying to get Robert Gordon Sproul , the University of California President, to provide for one in the budget. Despite multiple attempts, they continued to fail, primarily due to the Great Depression. However, in 1942, Sproul asked Paul W. Merrill from Mount Wilson to succeed Wright, but

990-445: A mathematical formula that the committee was able to use for data correlation. Pearson brought his correlation formula to his own Biometrics Laboratory. Pearson had volunteer and salaried computers who were both men and women. Alice Lee was one of his salaried computers who worked with histograms and the chi-squared statistics. Pearson also worked with Beatrice and Frances Cave-Brown-Cave . Pearson's lab, by 1906, had mastered

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1080-722: A mining engineer with such a handicap. Mayall's mother encouraged him to study whatever interested him the most, and to do it well, so he considered astronomy as an alternative to mining. After asking many professors in the astronomy department whether they enjoyed their work and whether they made a satisfactory wage, and being content with their answers, he transferred to the College of Letters and Science to major in astronomy. This did not set him back in his degree requirements because almost all of his first year studies had been in basic physical sciences and mathematics. Eventually Mayall discovered that he greatly enjoyed astronomy, and decided upon

1170-569: A nautical almanac in the 1840s, with Maria Mitchell being one of the best-known computers on the staff. Other innovations in human computing included the work done by a group of boys who worked in the Octagon Room of the Royal Greenwich Observatory for Astronomer Royal George Airy . Airy's computers, hired after 1835, could be as young as fifteen, and they were working on a backlog of astronomical data. The way that Airy organized

1260-718: A new committee, the Mathematical Tables Committee, which was the only professional organization for human computers in 1925. Human computers were used to predict the effects of building the Afsluitdijk between 1927 and 1932 in the Zuiderzee in the Netherlands . The computer simulation was set up by Hendrik Lorentz . A visionary application to meteorology can be found in the scientific work of Lewis Fry Richardson who, in 1922, estimated that 64,000 humans could forecast

1350-774: A relatively recently identified astronomical phenomenon. In contrast to the typical and well known gaseous nebulae within the plane of the Milky Way galaxy , IFNs lie beyond the main body of the galaxy. Most nebulae can be described as diffuse nebulae, which means that they are extended and contain no well-defined boundaries. Diffuse nebulae can be divided into emission nebulae , reflection nebulae and dark nebulae . Visible light nebulae may be divided into emission nebulae, which emit spectral line radiation from excited or ionized gas (mostly ionized hydrogen ); they are often called H II regions , H II referring to ionized hydrogen), and reflection nebulae which are visible primarily due to

1440-558: 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 regions, such as in the Pillars of Creation in the Eagle Nebula . In these regions, the formations of gas, dust, and other materials "clump" together to form denser regions, which attract further matter and eventually become dense enough to form stars . The remaining material

1530-408: Is debatable for the following reason: HBC is a computational technique where a machine outsources certain parts of a task to humans to perform, which are not necessarily algorithmic. In fact, in the context of HBC most of the time humans are not provided with a sequence of exact steps to be executed to yield the desired result; HBC is agnostic about how humans solve the problem. This is why "outsourcing"

1620-412: Is expected to spawn a planetary nebula about 12 billion years after its formation. A supernova occurs when a high-mass star reaches the end of its life. When nuclear fusion in the core of the star stops, the star collapses. The gas falling inward either rebounds or gets so strongly heated that it expands outwards from the core, thus causing the star to explode. The expanding shell of gas forms

1710-404: Is then thought to form planets and other planetary system objects. Most nebulae are of vast size; some are hundreds of light-years in diameter. A nebula that is visible to the human eye from Earth would appear larger, but no brighter, from close by. The Orion Nebula , the brightest nebula in the sky and occupying an area twice the angular diameter of the full Moon , can be viewed with

1800-677: The Andromeda Galaxy is located. He also cataloged the Omicron Velorum star cluster as a "nebulous star" and other nebulous objects, such as Brocchi's Cluster . The supernovas that created the Crab Nebula , SN 1054 , was observed by Arabic and Chinese astronomers in 1054. In 1610, Nicolas-Claude Fabri de Peiresc discovered the Orion Nebula using a telescope. This nebula was also observed by Johann Baptist Cysat in 1618. However,

1890-544: The Cape of Good Hope , most of which were previously unknown. Charles Messier then compiled a catalog of 103 "nebulae" (now called Messier objects , which included what are now known to be galaxies) by 1781; his interest was detecting comets , and these were objects that might be mistaken for them. The number of nebulae was then greatly increased by the efforts of William Herschel and his sister, Caroline Herschel . Their Catalogue of One Thousand New Nebulae and Clusters of Stars

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1980-628: The Cowles Commission and the National Research Council . Following World War II, the National Advisory Committee for Aeronautics (NACA) used human computers in flight research to transcribe raw data from celluloid film and oscillograph paper and then, using slide rules and electric calculators , reduced the data to standard engineering units. Margot Lee Shetterly 's biographical book, Hidden Figures (made into

2070-494: The Great Debate , it became clear that many "nebulae" were in fact galaxies far from the Milky Way . Slipher and Edwin Hubble continued to collect the spectra from many different nebulae, finding 29 that showed emission spectra and 33 that had the continuous spectra of star light. In 1922, Hubble announced that nearly all nebulae are associated with stars and that their illumination comes from star light. He also discovered that

2160-639: The Kitt Peak National Observatory until his retirement in 1971. Under his leadership KPNO, and the Cerro Tololo Inter-American Observatory , developed into two of the world's top research observatories, equipped with premier telescopes. Mayall was responsible for the construction of the 4-meter (160 in) Kitt Peak reflector, which was named after him. When Mayall died in 1993, his ashes were spread high on an empty ridge of Kitt Peak. Mayall's father, Edwin L. Mayall Sr.,

2250-686: The West Area Computers , a group of African-American women who worked as computers at Langley. Human computing was, at the time, considered menial work. On November 8, 2019, the Congressional Gold Medal was awarded "In recognition of all the women who served as computers, mathematicians, and engineers at the National Advisory Committee for Aeronautics and the National Aeronautics and Space Administration (NASA) between

2340-443: The positions of planets . They often hired a "computer" to assist them. For some people, such as Johannes Kepler , assisting a scientist in computation was a temporary position until they moved on to greater advancements. Before he died in 1617, John Napier suggested ways by which "the learned, who perchance may have plenty of pupils and computers" might construct an improved logarithm table . Computing became more organized when

2430-548: The ultraviolet radiation it emits can ionize the surrounding nebula that it has thrown off. The Sun will produce a planetary nebula and its core will remain behind in the form of a white dwarf . Objects named nebulae belong to four major groups. Before their nature was understood, galaxies ("spiral nebulae") and star clusters too distant to be resolved as stars were also classified as nebulae, but no longer are. Not all cloud-like structures are nebulae; Herbig–Haro objects are an example. Integrated flux nebulae are

2520-506: The 1930s and the 1970s." As electrical computers became more available, human computers, especially women, were drafted as some of the first computer programmers . Because the six people responsible for setting up problems on the ENIAC (the first general-purpose electronic digital computer built at the University of Pennsylvania during World War II) were drafted from a corps of human computers,

2610-458: The 1956 paper he co-authored with Humason and Allan Sandage, on the rate of expansion of the Universe. The paper listed over 800 redshift values (300 determined by Mayall) for galaxies measured from 1935 to 1955 at Lick, Wilson and Palomar. At Lick, he also studied galactic dynamics , such as the rotational motion of the Andromeda and Triangulum galaxies. He presented this work at a symposium on

2700-427: The 200-inch (5.1 m) Hale Telescope was completed at Palomar Observatory. Mayall and other young faculty at Lick thought that the older faculty such as Moore and Wright were too committed to the small telescopes and should have tried harder to obtain a larger reflector. Unknown to Mayall, Lick observatory director William H. Wright and his predecessor, Robert G. Aitken , had both tried in secret to raise money for

2790-455: The 7,000-foot (2,100 m) Kitt Peak , and oversaw the building of its first telescope, the 84-inch (2.1 m) reflector which was completed in the spring of 1960. However, the AURA board decided that Meinel was not well suited for the job and chose Mayall to replace him on October 1, 1960, even though he had no previous administrative experience. Mayall had previously been appointed (in 1958) as

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2880-460: The Crab Nebula was the remnant of a supernova observed and recorded in 1054 ( SN 1054 ), rather than a classical nova . Walter Baade was instrumental in stimulating and counseling Mayall after around 1939, taking on the role previously filled by Hubble. In 1941, together with Arthur Wyse and Lawrence Aller, Mayall studied the rotation of nearby galaxies and found that there was much matter that

2970-689: The Frenchman Alexis Claude Clairaut (1713–1765) divided the computation to determine the time of the return of Halley's Comet with two colleagues, Joseph Lalande and Nicole-Reine Lepaute . Human computers continued plotting the future movements of astronomical objects to create celestial tables for almanacs in the late 1760s. The computers working on the Nautical Almanac for the British Admiralty included William Wales , Israel Lyons and Richard Dunthorne . The project

3060-542: The H II region are known as photodissociation region . Examples of star-forming regions are the Orion Nebula , the Rosette Nebula and the Omega Nebula . Feedback from star-formation, in the form of supernova explosions of massive stars, stellar winds or ultraviolet radiation from massive stars, or outflows from low-mass stars may disrupt the cloud, destroying the nebula after several million years. Other nebulae form as

3150-743: The Harvard Computers and added new stars in successive volumes. Elizabeth Williams was involved in calculations in the search for a new planet, Pluto , at the Lowell Observatory . In 1893, Francis Galton created the Committee for Conducting Statistical Inquiries into the Measurable Characteristics of Plants and Animals which reported to the Royal Society . The committee used advanced techniques for scientific research and supported

3240-525: The Harvard Computers for free. Many of the women astronomers from this era were computers with possibly the best-known being Florence Cushman , Henrietta Swan Leavitt , and Annie Jump Cannon , who worked with Pickering from 1888, 1893, and 1896 respectively. Cannon could classify stars at a rate of three per minute. Mina Fleming , one of the Harvard Computers, published The Draper Catalogue of Stellar Spectra in 1890. The catalogue organized stars by spectral lines . The catalogue continued to be expanded by

3330-498: The Mount Wilson spectrographs used heavy glass lenses and prisms, which absorb ultraviolet radiation. While Mayall hoped to join the Mount Wilson team upon earning his doctorate, there were no openings during the Great Depression . Instead, he began his career at Lick, which was afforded by the number two janitor resigning and Mayall being given a one-year position as observing assistant with janitorial duties limited to maintaining

3420-465: The Octagon Room with a manager, pre-printed computing forms, and standardized methods of calculating and checking results (similar to the way the Nautical Almanac computers operated) would remain a standard for computing operations for the next 80 years. Women were increasingly involved in computing after 1865. Private companies hired them for computing and to manage office staff. In the 1870s,

3510-768: The UC Berkeley library to help support them both. Mayall generally did well at university, and was eventually elected to the Sigma Xi and Phi Beta Kappa honor societies. However, at mid-term examinations of his second year, he achieved poor grades in mineralogy and chemistry laboratory. At a meeting with the dean to discuss his grades the latter became aware that Mayall was color blind , which prevented him from observing small color changes in bead and flame tests , and also kept him from seeing small color changes in precipitations and titrations . Mayall's adviser recommended that he change his major , as he would not be able to graduate as

3600-582: The United States Signal Corps created a new way of organizing human computing to track weather patterns. This built on previous work from the US Navy and the Smithsonian meteorological project . The Signal Corps used a small computing staff that processed data that had to be collected quickly and finished in "intensive two-hour shifts". Each individual human computer was responsible for only part of

3690-752: The age of 65, an event that was honored by a symposium held on his birthday, May 8. During his retirement, he continued to play an active role in many organizations, including the overview committee for Fermilab . He died on January 5, 1993, of complications caused by diabetes; his ashes were spread high on an empty ridge of Kitt Peak. Mayall was survived by his wife of 58 years, Kathleen Boxall, and their two children: Bruce Ian Mayall (1939) and Pamela Ann Mayall, their two grandchildren: Shane Nicholas Oakes (1977) and Bryce Oakes Mayall (1979), and great grand children Asa Mayall, Matthew Oakes and Kathryn Oakes Nebulae A nebula ( Latin for 'cloud, fog'; pl. : nebulae , nebulæ , or nebulas )

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3780-424: The art of mathematical table making. Human computers were used to compile 18th and 19th century Western European mathematical tables , for example those for trigonometry and logarithms . Although these tables were most often known by the names of the principal mathematician involved in the project, such tables were often in fact the work of an army of unknown and unsung computers. Ever more accurate tables to

3870-733: The beginning of the Universe. Together with Milton L. Humason and Allan R. Sandage , he wrote a 1956 paper concluding that the age of the Universe was six billion years (three times the prior estimate, and about half the modern value ), and its size three times larger than thought. After the United States entered World War II, Mayall accepted a position at the MIT Radiation Laboratory in Cambridge, Massachusetts to work on radar development. He began his work early in 1942 in Cambridge, which

3960-554: The committee decided upon the basic parameters of what would become the 120-inch (3.0 m) C. Donald Shane telescope . On March 7, Mayall joined Shane, Wright and Moore (not present at the March 6 meeting), at Mount Hamilton to choose the location upon which to build the reflector. During the long period of building the 120-inch (3.0 m) telescope, Mayall continued to use Lick's 36-inch (0.91 m) Crossley Reflector and focused his efforts on utilizing his slitless spectrograph, which

4050-503: The darkrooms and keeping instrument rooms clean. The following year, one of the senior astronomers joined the Berkeley department and his salary was split between Mayall and another young astronomer, Arthur Bambridge Wyse . On June 30, 1934, Mayall married Kathleen (Kay) Boxall from Los Angeles , who he had met during his two years in Pasadena . They lived in a small apartment that was part of

4140-507: The data. In the late nineteenth century Edward Charles Pickering organized the " Harvard Computers ". The first woman to approach them, Anna Winlock , asked Harvard Observatory for a computing job in 1875. By 1880, all of the computers working at the Harvard Observatory were women. The standard computer pay started at twenty-five cents an hour. There would be such a huge demand to work there, that some women offered to work for

4230-568: The depletion of the male labor force due to the draft , many computers during World War II were women, frequently with degrees in mathematics. In the 1940s, women were hired to examine nuclear and particle tracks left on photographic emulsions. In the Manhattan Project , human computers working with a variety of mechanical aids assisted numerical studies of the complex formulas related to nuclear fission . Human computers were involved in calculating ballistics tables during World War I. Between

4320-471: The different types of nebulae. Some nebulae form from gas that is already in the interstellar medium while others are produced by stars. Examples of the former case are giant molecular clouds , the coldest, densest phase of interstellar gas, which can form by the cooling and condensation of more diffuse gas. Examples of the latter case are planetary nebulae formed from material shed by a star in late stages of its stellar evolution . Star-forming regions are

4410-481: The early 17th century (the first known written reference dates from 1613), meant "one who computes": a person performing mathematical calculations , before calculators became available. Alan Turing described the "human computer" as someone who is "supposed to be following fixed rules; he has no authority to deviate from them in any detail." Teams of people, often women from the late nineteenth century onwards, were used to undertake long and often tedious calculations;

4500-405: The emission spectrum nebulae are nearly always associated with stars having spectral classifications of B or hotter (including all O-type main sequence stars ), while nebulae with continuous spectra appear with cooler stars. Both Hubble and Henry Norris Russell concluded that the nebulae surrounding the hotter stars are transformed in some manner. There are a variety of formation mechanisms for

4590-510: The expelled gases, producing emission nebulae with spectra similar to those of emission nebulae found in star formation regions. They are H II regions , because mostly hydrogen is ionized, but planetary are denser and more compact than nebulae found in star formation regions. Planetary nebulae were given their name by the first astronomical observers who were initially unable to distinguish them from planets, and who tended to confuse them with planets, which were of more interest to them. The Sun

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4680-420: The explosion lies in the center of the Crab Nebula and its core is now a neutron star . Still other nebulae form as planetary nebulae . This is the final stage of a low-mass star's life, like Earth's Sun. Stars with a mass up to 8–10 solar masses evolve into red giants and slowly lose their outer layers during pulsations in their atmospheres. When a star has lost enough material, its temperature increases and

4770-516: The first detailed study of the Orion Nebula was not performed until 1659 by Christiaan Huygens , who also believed he was the first person to discover this nebulosity. In 1715, Edmond Halley published a list of six nebulae. This number steadily increased during the century, with Jean-Philippe de Cheseaux compiling a list of 20 (including eight not previously known) in 1746. From 1751 to 1753, Nicolas-Louis de Lacaille cataloged 42 nebulae from

4860-621: The funds proposed in the budget by Sproul. Mayall and Gerald E. Kron sent a letter to Sproul representing the younger Lick staff members, in which they requested a meeting to discuss the kind of telescope to be built. They met with Sproul in December 1944 in Sproul's Los Angeles office. Mayall spoke of the key need for a telescope exceeding 90 inches (2.3 m). At the Caltech optical shop in Pasadena he had seen

4950-433: The lack of accurate magnitude standards for the faint galaxies that were measured and by the (then unrealized) very strong tendency of galaxies to cluster . While working on his thesis, Mayall had an idea of designing a small, fast slitless spectrograph , optimized for nebulae and galaxies. He believed that if it were used in conjunction with the Crossley reflector it would make that facility competitive for at least some of

5040-503: The light they reflect. Reflection nebulae themselves do not emit significant amounts of visible light, but are near stars and reflect light from them. Similar nebulae not illuminated by stars do not exhibit visible radiation, but may be detected as opaque clouds blocking light from luminous objects behind them; they are called dark nebulae . Although these nebulae have different visibility at optical wavelengths, they are all bright sources of infrared emission, chiefly from dust within

5130-505: The little astronomy village on the Mount Hamilton summit, where all Lick astronomers resided at that time. Using his newly built spectrograph, Mayall was the first to determine the radial velocities of many knots of gas in the Crab Nebula . Using these data and the previously published angular rate of expansion of the nebula, he was able to estimate its distance. Consequently, he became the first person to recognize and demonstrate that

5220-503: The management of his project and feeling his talents were not being well used, he transferred again in February 1944 to Caltech to work on the development of large rockets. There he became an expert on high-speed photography , which was used to analyze rocket trajectories. In the spring of 1945, he was transferred to a secret atomic bomb project that also required high-speed photography. He visited Los Alamos twice, including once around

5310-531: The men at war, most of these new computers were women and many were college educated." This would happen again during World War II , as more men joined the fight, college educated women were left to fill their positions. One of the first female computers, Elizabeth Webb Wilson, was hired by the Army in 1918 and was a graduate of George Washington University . Wilson "patiently sought a war job that would make use of her mathematical skill. In later years, she would claim that

5400-778: The naked eye but was missed by early astronomers. Although denser than the space surrounding them, most nebulae are far less dense than any vacuum created on Earth (10 to 10 molecules per cubic centimeter) – a nebular cloud the size of the Earth would have a total mass of only a few kilograms . Earth's air has a density of approximately 10 molecules per cubic centimeter; by contrast, the densest nebulae can have densities of 10 molecules per cubic centimeter. Many nebulae are visible due to fluorescence caused by embedded hot stars, while others are so diffused that they can be detected only with long exposures and special filters. Some nebulae are variably illuminated by T Tauri variable stars. Originally,

5490-638: The nearly completed 120-inch (3.0 m) Pyrex glass disc that was initially planned to be used as a flat in the auto- collimation test of the 200-inch (5.1 m) Palomar mirror and urged Sproul to have the Lick telescope use a mirror of that size. Much to their surprise, Sproul agreed. Shane was appointed chairman of a committee formed by Sproul in the beginning of 1945, to plan the new reflector. Other committee members included Mayall, Moore, Walter S. Adams and Ira S. Bowen . The committee functioned primarily through correspondence. Mayall's first letter helped to convince Shane that 120 inches (3.0 m)

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5580-401: The nebulae. Planetary nebulae are the remnants of the final stages of stellar evolution for mid-mass stars (varying in size between 0.5-~8 solar masses). Evolved asymptotic giant branch stars expel their outer layers outwards due to strong stellar winds, thus forming gaseous shells while leaving behind the star's core in the form of a white dwarf . Radiation from the hot white dwarf excites

5670-473: The observatory. This was Mayall's first visit to the observatory where he would spend much of his career. After visiting, he read all the astronomy books available in the local libraries, although he did not at that time imagine making astronomy his profession. Mayall began college in the fall of 1924 at the University of California, Berkeley , studying for a degree in mining . He took up residence with his mother in an apartment on Durant Avenue, and worked at

5760-452: The result of supernova explosions; the death throes of massive, short-lived stars. The materials thrown off from the supernova explosion are then ionized by the energy and the compact object that its core produces. One of the best examples of this is the Crab Nebula , in Taurus . The supernova event was recorded in the year 1054 and is labeled SN 1054 . The compact object that was created after

5850-576: The second director of Kitt Peak National Observatory (KPNO). With financial support from the National Science Foundation , several universities had formed a consortium — the Association of Universities for Research in Astronomy (AURA). Its purpose was to create and run a research observatory for American astronomers. The first director was Aden B. Meinel , who chose the site near Tucson at

5940-559: The sensitivity of Mayall's eyes that could reach down to +17 visual magnitude using the 36-inch (0.91 m) telescope. Mayall's eyesight later deteriorated to the point that he could no longer read. The new 120-inch (3.0 m) telescope became operational at the beginning of 1960. Mayall immediately began using it, although he left Lick in September of that year. Mayall moved on from the University of California (after more than 25 years progressing from student to astronomer), to become

6030-509: The spectra of about 70 nebulae. He found that roughly a third of them had the emission spectrum of a gas . The rest showed a continuous spectrum and were thus thought to consist of a mass of stars. A third category was added in 1912 when Vesto Slipher showed that the spectrum of the nebula that surrounded the star Merope matched the spectra of the Pleiades open cluster . Thus, the nebula radiates by reflected star light. In 1923, following

6120-592: The structure of the Milky Way on June 23, 1950, at the University of Michigan in Ann Arbor. This work demonstrated the inner solid-body rotation and the outer Keplerian motion. In 1953, together with O. J. Eggen, Mayall identified six likely globular clusters (including Mayall II ) around the Andromeda Galaxy in a Palomar 48-inch schmidt plate exposed in 1948 that was provided to them by Hubble. Gerry Kron marveled at

6210-581: The term "nebula" was used to describe any diffused astronomical object , including galaxies beyond the Milky Way . The Andromeda Galaxy , for instance, was once referred to as the Andromeda Nebula (and spiral galaxies in general as "spiral nebulae") before the true nature of galaxies was confirmed in the early 20th century by Vesto Slipher , Edwin Hubble , and others. Edwin Hubble discovered that most nebulae are associated with stars and illuminated by starlight. He also helped categorize nebulae based on

6300-546: The then head of the Lick stellar spectroscopy program, Joseph Haines Moore , encouraged him to develop his spectrograph. The device was constructed by the Lick Observatory's own workshop, and proved to be more efficient for extended, low-surface-brightness objects, particularly in the ultraviolet part of the spectrum , thus confirming the expectations of Mayall. With Wright's strong encouragement, Mayall had used fused quartz to make ultraviolet transmitting optics, whereas

6390-721: The time of the Trinity test . By October 1, 1945, the war had ended and Mayall had returned to astronomical research at Lick. During World War II Mayall became an important influence on Lick Observatory's future. Ever since 1931, when he had returned to Lick and Berkeley after serving two years as an assistant at Mount Wilson, he had felt strongly that Mount Hamilton required a larger telescope. The astronomers at Lick were proud of their ability to achieve important results with Lick's small 36-inch (0.91 m) Crossley reflector. Its diminutive size first became apparent in 1908, when Mount Wilson's 60-inch (1.5 m) telescope saw first light . This

6480-505: The two world wars, computers were used in the Department of Agriculture in the United States and also at Iowa State College . The human computers in these places also used calculating machines and early electrical computers to aid in their work. In the 1930s, The Columbia University Statistical Bureau was created by Benjamin Wood . Organized computing was also established at Indiana University ,

6570-541: The type of light spectra they produced. Around 150 AD, Ptolemy recorded, in books VII–VIII of his Almagest , five stars that appeared nebulous. He also noted a region of nebulosity between the constellations Ursa Major and Leo that was not associated with any star . The first true nebula, as distinct from a star cluster , was mentioned by the Muslim Persian astronomer Abd al-Rahman al-Sufi in his Book of Fixed Stars (964). He noted "a little cloud" where

6660-459: The war spared her from the 'Washington social whirl', the rounds of society events that should have procured for her a husband" and instead she was able to have a career. After the war, Wilson continued with a career in mathematics and became an actuary and turned her focus to life tables . Human computers played integral roles in the World War II war effort in the United States, and because of

6750-451: The weather for the whole globe by solving the attending differential primitive equations numerically. Around 1910 he had already used human computers to calculate the stresses inside a masonry dam. It was not until World War I that computing became a profession. "The First World War required large numbers of human computers. Computers on both sides of the war produced map grids, surveying aids, navigation tables and artillery tables. With

6840-437: The work of several scientists. W.F. Raphael Weldon , the first scientist supported by the committee worked with his wife, Florence Tebb Weldon, who was his computer. Weldon used logarithms and mathematical tables created by August Leopold Crelle and had no calculating machine. Karl Pearson , who had a lab at the University of London , felt that the work Weldon did was "hampered by the committee". However, Pearson did create

6930-441: The work that Humason and Hubble were doing with the larger Mt. Wilson telescopes. It was never expected to compete with the Mount Wilson 100-inch (2.5 m) instrument for stars or elliptical galaxies , which have condensed and relatively bright nuclei. The spectrograph was to be used instead to study extended, low-surface-brightness gaseous nebulae or irregular galaxies . Mayall's thesis advisor , William Hammond Wright , and

7020-571: The work was divided so that this could be done in parallel. The same calculations were frequently performed independently by separate teams to check the correctness of the results. Since the end of the 20th century, the term "human computer" has also been applied to individuals with prodigious powers of mental arithmetic , also known as mental calculators . Astronomers in Renaissance times used that term about as often as they called themselves " mathematicians " for their principal work of calculating

7110-453: The world's first professional computer programmers were women, namely: Kay McNulty , Betty Snyder , Marlyn Wescoff , Ruth Lichterman , Betty Jean Jennings , and Fran Bilas . The term "human computer" has been recently used by a group of researchers who refer to their work as "human computation". In this usage, "human computer" refers to activities of humans in the context of human-based computation (HBC). This use of "human computer"

7200-399: Was accentuated by the opening of the 72-inch (1.8 m) Dominion Astrophysical Observatory in 1917, and Mount Wilson's even larger 100-inch (2.5 m) Hooker telescope in 1919. Mayall was adept at working with the small Crossley, but understood that it could never really stand up to a competing telescope that collected nine times the amount of light. This was only going to get worse when

7290-601: Was an engineer for a manufacturing company in Illinois . His mother, Olive Ulrich Mayall, despite never attending college herself, set high educational standards for Mayall and his younger brother (Edwin Jr., born 1907). Sometime between his brother's birth and 1913, the family moved to California's Modesto area, where Mayall entered first grade . Some time before 1917, they moved again, to Stockton where they remained until 1924 and Mayall's graduation from Stockton High School (except for

7380-452: Was feasible instead of just 90-inch (2.3 m). Mayall helped to bridge the gap between the experienced team of telescope designers in Pasadena and Shane, who was more experienced as a university administrator and professor. Adams and the executive officer of the 200-inch (5.1 m) project, John August Anderson , shared their experience, drawings and plans with the Lick design committee. On March 6, 1945, with both Mayall and Shane present,

7470-685: Was named the Nicholas U. Mayall Telescope in his honor. Mayall was intimately involved in the expansion of the national observatory to the Southern Hemisphere in what eventually became the Cerro Tololo Interamerican Observatory (CTIO). The 4-metre (160 in) Víctor M. Blanco Telescope at CTIO (identical to the Mayall Telescope at Kitt Peak) saw first light in 1974 and was completed in 1976. Mayall retired in 1971, at

7560-451: Was optimized for extended, low-surface-brightness clusters, galaxies, and nebulae. In 1946, he completed his pre-war effort to get integrated spectra of globular clusters and published the work. His paper was key in demonstrating that the system of Milky Way globular clusters shares only slightly the galactic rotation found in the flattened disc of interstellar matter and young stars in our galaxy. In 1948, Mayall serendipitously discovered

7650-512: Was overseen by Nevil Maskelyne . Maskelyne would borrow tables from other sources as often as he could in order to reduce the number of calculations his team of computers had to make. Women were generally excluded, with some exceptions such as Mary Edwards who worked from the 1780s to 1815 as one of thirty-five computers for the British Nautical Almanac used for navigation at sea. The United States also worked on their own version of

7740-442: Was published in 1786. A second catalog of a thousand was published in 1789, and the third and final catalog of 510 appeared in 1802. During much of their work, William Herschel believed that these nebulae were merely unresolved clusters of stars. In 1790, however, he discovered a star surrounded by nebulosity and concluded that this was a true nebulosity rather than a more distant cluster. Beginning in 1864, William Huggins examined

7830-575: Was the only time during his adult life that he resided outside California or Arizona. However, the climate of Massachusetts was unlike that of California, which he and his family were accustomed to, and in the middle of 1943 he arranged a transfer to the Pasadena Mount Wilson Observatory offices. Many wartime Office of Scientific Research and Development (OSRD) projects related to optics, aerial gunnery, aerial photography , and bombing tactics were already in progress there. Unhappy with

7920-555: Was to count the number of galaxies per unit area on the sky as a function of position on direct plates taken with the Crossley reflector at Lick. This should have supplemented the counts Hubble himself was making using the 60-inch (1.5 m) and 100-inch (2.5 m) telescopes at Mount Wilson. Mayall successfully completed his thesis and was awarded his PhD degree in 1934. Hubble complimented Mayall for his work, although significant results were never achieved (nor by Hubble either) due to

8010-465: Was too faint to be observed, but which could be detected by way of its gravitational effect. He spent about three years until 1942 researching 50 Milky Way globular clusters , and found the Milky Way had about one half of the mass previously supposed. While at the Lick Observatory , Mayall collaborated on a 20-year project with astronomers at Mount Palomar and Mount Wilson on the Big Bang theory of

8100-559: Was turned down. Agitated by the refusal, Sproul changed his stance and told the regents that they had to find a way to raise money for a new telescope once the war ended. At about this time, Sproul promised or secretly appointed C. Donald Shane as director of Lick, to take over when the war ended. The plan for a large telescope was leaked around September 1944 in the form of the University's budget proposals. Wright and Joseph H. Moore, interim wartime Lick director, imagined an 85-inch (2.2 m) or 90-inch (2.3 m) reflector based upon

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