Nicholas U. Mayall
Born	May 9, 1906(1906-05-09) Moline, Illinois, U.S.
Died	January 5, 1993 (aged 86) Tucson, Arizona
Residence	U.S.
Nationality	American
Fields	Astronomy
Institutions	Mount Wilson Observatory Lick Observatory Kitt Peak National Observatory Cerro Tololo Inter-American Observatory
Alma mater	University of California, Berkeley

Nicholas Ulrich Mayall (May 9, 1906 – January 5, 1993) was an American observational astronomer. After obtaining his doctorate from the University of California, Berkeley, Mayall began his career at the Lick Observatory, where he remained until 1960 except for a brief leave to MIT's Radiation Laboratory to help the war effort during World War II. While at Lick, he added to the knowledge of nebulae, supernovae, spiral galaxy internal motions, the redshifts of galaxies, and the origin, age, and size of the universe.^[1][2] He was a key player in both the planning and construction of what was to become Lick's 120-inch (3.0 m) telescope, which represented a major improvement over Lick's prior 36-inch (0.91 m) telescope.

Mayall also spent 11 years as director of the Kitt Peak National Observatory, where he shepherded it and the Cerro Tololo Inter-American Observatory into top research observatories, with premiere telescopes, before retiring in 1971.^[3]

[edit] Early life

Mayall's father, Edwin L. Mayall, Sr., was an engineer for a manufacturing company in Illinois. His mother was Olive Ulrich Mayall. Although she never attended college, she set high educational standards for Mayall and his younger brother, Edwin, Jr., who was born in 1907. Sometime between his brother's birth and 1913, the family moved to California's Modesto area, where Mayall entered first grade. Sometime before 1917, they proceeded to Stockton where they remained (except for a brief return to Peoria, Illinois during 1918–1919) through 1924 and Mayall's Stockton High School^[4] graduation. During this period, presumably during his high school years, his parents were divorced.^[5]

During his senior year, in the fall of 1923, Mayall was secretary of the science club and set up the club's visit to the Lick Observatory. His father gave him use of his car, a Moline Knight, to transport the club members up the dirt and gravel winding mountain road leading to the observatory. This was his first visit to the observatory where he would be a student and spend many years of his career. After visiting, he read all the astronomy books available in the local libraries, although he did not at this time imagine making astronomy his profession.^[6][7]

[edit] Education

Mayall began college in the fall of 1924 at the University of California, Berkeley, pursuing a degree in mining. He had an apartment with his mother on Durant Avenue. He worked at the school's library to earn money necessary for their needs. Mayall generally did well in school and was eventually elected to both the Sigma Xi and Phi Beta Kappa. However, at mid-terms of his second year, he was getting poor grades in both mineralogy and chemistry laboratory. He met with the dean to discuss his grades and the dean was made aware that he was color-blind. This prohibited him from observing small color changes in bead and flame tests, and also kept him from seeing small color changes in precipitations and titrations. His adviser directed him to change his major as he would not be able to graduate as a mining engineer with such a handicap.^[8][9]

Mayall now began to consider pursuing an education in astronomy. His mother encouraged him to pursue whatever interested him the most and to do it well. He surveyed many professors in the astronomy department as to whether they enjoyed their work and whether they made a satisfactory wage and found that the answers were yes. Therefore, he transferred to the College of Letters and Science in order 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 math. He discovered that he greatly enjoyed astronomy and thus decided upon a course of graduate level study followed by a career as a research scientist.^[10][11]

After graduating in 1928,^[11] he 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 1929–1931, where he assisted luminaries such as Edwin Hubble, Paul W. Merrill, and Milton Humason.^[12][13] This led to publishing papers with Seth Barnes Nicholson and others about Pluto, shortly after its discovery, on its mass^[14][15] and orbit.^{[2][16][17][18][19]}

Mayall returned to Berkeley in 1931 to pursue graduate level work. His thesis topic, suggested by Hubble, 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 supplemented the counts Hubble himself was making using the 60-inch (1.5 m) and 100-inch (2.5 m) telescopes at Mt. Wilson. He completed his thesis and was awarded his Ph.D. degree in 1934.^[20] Hubble complimented Mayall for his work, although significant results were never achieved (nor for Hubble either) due to 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.^[21][22]

While working on his thesis, Mayall had the idea to design and build a small, fast slitless spectrograph^[23] that was optimized for nebulae and galaxies. This he proposed to be used with the Crossley Reflector to make it competitive for at least some of the work that Milton L. Humason and Hubble were doing with the larger Mt. Wilson telescopes. It was never expected to compete with the Mt. Wilson 100-inch (2.5 m) for stars or elliptical galaxies, which have condensed, relatively bright nuclei, but instead be more efficient for extended, low-surface-brightness gaseous nebulae and irregular galaxies. Mayall's thesis adviser, William Hammond Wright, and the then head of the Lick stellar spectroscopy program, Joseph Haines Moore, encouraged Mayall to pursue the spectrograph design. The spectrograph was constructed at the Lick Observatory shop. When put into use, it proved to indeed be more efficient for extended, low-surface-brightness objects. This was accentuated in the ultraviolet part of the spectrum because, with Wright’s strong encouragement, Mayall used fused quartz to make ultraviolet transmitting optics. This was distinct from the Mt. Wilson spectrographs that utilized heavy glass lenses and prisms that absorb ultraviolet radiation.^[24][25][26]

[edit] Lick Observatory

The main Lick Observatory building and the South (large) Dome that houses the south telescope.

While Mayall hoped to join the Mount Wilson team upon getting his doctoral, there were no openings during the Great Depression. Instead he began his career at Lick. This 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 the darkrooms and 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 of Los Angeles. They had met during his two years in Pasadena. They lived in a small apartment that was part of the little astronomy village where all the Lick astronomers lived on the Mount Hamilton summit.^[27][28]

Using his spectrograph, Mayall was the first to determine the radial velocities of many knots in the Crab Nebula.^[17] Using his 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 the Crab nebula was the remnant of a supernova first observed and recorded in 1054, rather than a classical nova.^[29][30] Walter Baade was instrumental in stimulating and counseling Mayall after around 1939, taking on the role previously filled by Hubble.^[31]

In 1941, together with Arthur Bambridge Wyse and Lawrence Hugh Aller, he studied the rotation of nearby galaxies and found that there was much matter that was too faint to see, but which could be detected by way of its gravitational effect.^[32] Mayall spent about three years researching fifty Milky Way globular clusters up until 1942 and found the Milky Way had about one half the mass as previously thought.^[33]

While at the Lick Observatory, he collaborated on a 20-year project with astronomers at Mount Palomar and Mount Wilson on the Big Bang theory of 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 6 billion years (three times the prior estimate), and its size three times larger than thought.^[2][34]

[edit] World War II

Mayall accepted a position at the MIT's Radiation Laboratory in Cambridge, Massachusetts, to work on radar development during World War II. Early in 1942, he began his work at Cambridge, which was the only time in his adult life that he resided other than in California and Arizona. However, the climate of Boston 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 Mt. Wilson Observatory offices. Many wartime Office of Scientific Research and Development (OSRD) projects related to optics, aerial gunnery, aerial photography, and bombing tactics were in progress there. Unhappy with the management of his project and feeling like his talents were not being used well, he transferred again in February 1944 to Caltech to work on big rocket development. There he became an expert on high-speed photography that was needed to analyze rocket trajectories. In the spring of 1945 he was transferred to a very secret atomic bomb project that required very-high-speed photography. He visited Los Alamos twice, once near the time of the Trinity test. By October 1, 1945, the war had ended and Mayall had returned to astronomical research at Lick.^[35][36][37]

[edit] 120-inch (3.0 m) telescope

The Lick 120-inch (3.0 m) telescope, with the dome open for maintenance

Mayall was an important influence in determining the Lick Observatory's future during World War II. Ever since 1931 when he had returned to Lick and Berkley after serving two years as an assistant at Mount Wilson, he had felt strongly that Mount Hamilton required a larger telescope.^[38] 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 was accentuated by the 72-inch (1.8 m) Dominion Astrophysical Observatory in 1917 and Mount Wilson's even larger 100-inch (2.5 m) in 1919. Mayall was adept at working with the small Crossley but understood that it could never really stand up to a telescope that collected nine times the amount of light. This was only going to get worse when the 200-inch (5.1 m) Palomar was completed. Mayall and other young faculty at Lick thought that older Moore and Wright were too complacent with the small telescopes and should have tried harder to attain a larger reflector.^[39]

Unbeknownst to Mayall, Lick observatory director William H. Wright and the prior director, Robert G. Aitken, had both tried in secret to raise money for 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. Although trying multiple times, they continued to fail, primarily due to the Great Depression. However, in 1942, Sproul wanted Paul W. Merrill from Mt. Wilson to succeed Wright and he was turned down. Agitated by the refusal, Sproul changed his stance and told the regents that they had to figure out 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 when the war ended.^[39]

The plan for a large telescope was leaked around September 1944 in the form of the University's budget proposals. Joseph H. Moore, interim wartime Lick director, and Wright imagined an 85-inch (2.2 m) or 90-inch (2.3 m) reflector based upon the funds proposed in the budget by Sproul. Mayall and Gerald E. Kron sent a letter to Sproul as representing the younger Lick staff members requesting 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 the nearly completed 120-inch (3.0 m) Pyrex glass disk that was initially planned to be used as a flat in the auto-collimation test of the 200-inch (5.1 m) Palomar mirror^[40] and argued to Sproul to have the Lick telescope use that size mirror. Much to their surprise, Sproul agreed.^[39][41]

Shane was 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. Doing most of their work by letter, Mayall began by convincing the others that 120 inches (3.0 m) was feasible. 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, the committee decided upon the basic parameters of what would become the 120-inch (3.0 m) Lick telescope. On March 7, Mayall joined Shane, Wright, and Moore (not present at the March 6 meeting) at Mt. Hamilton to choose the location upon which to build the reflector.^[39]

[edit] Postwar Lick research

HST image of Mayall II, assembled from images in visible and near-infrared in July 1994

During the long period of building the 120-inch (3.0 m) telescope, Mayall continued to use Lick's difficult 36-inch (0.91 m) Crossley Reflector and focused his efforts on utilizing his fast spectrograph, which 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 a little bit in the galactic rotation found in the flattened system of interstellar matter and young stars in our galaxy.^[42][43][44] In 1948, Mayall accidentally discovered a type 2 supernova while conducting other research.^[45][46]

Other research he performed included the twenty year collaboration (formulated in 1935 by Hubble) with Milton Humason to gather redshift values for all northern galaxies exceeding 13 visual magnitude. Mayall handled the brighter ones on the Crossley while Humason tackled the dimmer ones using the Mount Wilson 100-inch (2.5 m). This work resulted in the 1956 paper he co-authored with Humason and Allan Sandage on the rate of expansion of the universe that listed over 800 redshift values (300 determined by Mayall) for galaxies measured from 1935 to 1955 at Lick, Wilson, and Palomar.^{[17][34][47][48][49][50]}

At Lick he also studied galaxy motion, such as the rotational motion of the Andromeda and Triangulum galaxies.^[2][17][51] He presented this work at a symposium on the structure of the Milky Way in June 23, 1950 at the University of Michigan in Ann Arbor.^[51] This work demonstrated the inner solid-body rotation and the outer Keplerian motion.^[17] Gerry Kron marveled at the sensitivity of Mayall's eyes that could reach down to 17 visual magnitude using the 36-inch (0.91 m) telescope.^[17] Sadly, his eyesight deteriorated in later life to the point that he could no longer read.^[17]

The 120-inch (3.0 m) telescope became operational in the beginning of 1960 and Mayall began using it,^[52] however, he left Lick in September of that year.^[53]

[edit] Kitt Peak National Observatory

Overview of some of the telescopes at the Kitt Peak National Observatory

Aerial view of the Cerro Tololo Interamerican Observatory

Mayall on March 2, 1973 viewing through the telescope to be named in his honor

Mayall moved on from the University of California (after more than 25 years^[36] progressing from student to astronomer), to become the second director of Kitt Peak National Observatory.^[54] With financial support from the National Science Foundation, several universities formed a consortium—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 7,000-foot (2,100 m) Kitt Peak and oversaw the building of its 84-inch (2.1 m) reflector that was finished in the spring of 1960.

However, the AURA board decided that Meinel was not suited for the job and chose Mayall to replace him on October 1, 1960,^[55] even though he had no administrative experience, although Mayall had previously been appointed in 1958 as 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 take the offer.^{[56][57][58][59]}

As director, Mayall oversaw the building of the 4-metre (160 in) Kitt peak reflector,^[60] which was named in his honor on June 20, 1973.^[61][62] It was still being built when he retired in 1971 and was completed in 1973.^[63] He was intimately involved in the expansion of the national observatory to the Southern hemisphere in what eventually became the Cerro Tololo Interamerican Observatory. The 4-metre (160 in) telescope there (identical to the Kitt peak one) was commissioned in 1974 and completed in 1976.^{[64][58][61][65][52]}

[edit] Retirement

In 1971, at the age of sixty-five, Mayall retired.^[66][67] His retirement was honored with a symposium on his 65^th birthday, May 8, 1971.^[17][68] During retirement, he continued participation in many organizations. This included the overview committee for Fermilab.^[17] He died on January 5, 1993 of complications from diabetes and his ashes were spread high on an empty ridge of Kitt Peak.^[2][69] Surviving Mayall were his widow, Kathleen Boxall,^[2] his wife for 58 years.^[17] They had two children, Bruce I. Mayall and Pamela Ann Mayall, who at the time of his death, lived in Mission Viejo, California and Snowflake, Arizona, respectively.^[2][17]

[edit] Honors

[edit] Bibliography

[edit] See also

• IC 10—Mayall was first to suggest that it is extragalactic.

[edit] References

[edit] Cited sources

[edit] External links

• Mayall and others inspecting the Mayall 4-meter primary blank.
• Picture of Mayall next to the telescope named in his honor.
• Mayall observing the sun with others in 1964.