Nicholas Mayall

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 worked at the Lick Observatory, where he remained until 1960 except for a brief period at MIT's Radiation Laboratory during World War II.

During his time at Lick, Mayall 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 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.

Mayall spent 11 years as director of the Kitt Peak National Observatory until his retirement in 1971. Under his leadership it, and the Cerro Tololo Inter-American Observatory, developed into two of the world's top research observatories, equipped with premiere telescopes.^[3] Mayall was responsible for the construction of the 4-metre (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.

Early life

Mayall's father, Edwin L. Mayall, Sr., was an engineer for a manufacturing company in Illinois. His mother, Olive Ulrich Mayall, although never attending college, set high educational standards for Mayall and his younger brother, Edwin, Jr., 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) until 1924 and Mayall's Stockton High School^[4] graduation. During this period, presumably during his high school years, Mayall's parents 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 permitted him to use his car, a Moline Knight, to transport the club members up the dirt and gravel winding mountain road leading to the observatory. This was Mayall's first visit to the observatory where he would spend many years 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.^[6][7]

Education

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 the school's library to help support them both. Mayall generally did well at university, and was eventually elected to the Sigma Xi and Phi Beta Kappa. However, at mid-terms 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 a mining engineer with such a handicap.^[8][9]

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 math. Eventually Mayall 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] 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 1929–1931, where he assisted luminaries such as Edwin Hubble, Paul W. Merrill, and Milton L. Humason.^[12][13] This activity resulted in him coauthoring papers on Pluto's mass^[14][15] and orbit with Seth Barnes Nicholson and others, shortly after Pluto's discovery^{[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 should have supplemented the counts Hubble himself was making using the 60-inch (1.5 m) and 100-inch (2.5 m) telescopes at Mt. Wilson. Mayall successfully 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 an idea of designing a small, fast slitless spectrograph,^[23] 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 the work that 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) 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 adviser, William Hammond Wright, and 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 expectations of Mayall. With Wright's strong encouragement, Mayall had used fused quartz to make ultraviolet transmitting optics, whereas the Mt. Wilson spectrographs used heavy glass lenses and prisms, which absorb ultraviolet radiation.^[24][25][26]

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 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 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 from Los Angeles, whom he had met during his two years in Pasadena. They lived in a small apartment that was part of the little astronomy village on the Mount Hamilton summit, where all Lick astronomers resided at that time.^[27][28]

Using his newly built spectrograph, Mayall was the first to determine the radial velocities of many knots in the Crab Nebula.^[17] 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 the Crab nebula was the remnant of a supernova 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 Wyse and Lawrence Aller, Mayall studied the rotation of nearby galaxies and found that there was much matter that was too faint to be observed, but which could be detected by way of its gravitational effect.^[32] He 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 supposed.^[33]

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 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]

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 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 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, 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 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]

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 committed to the small telescopes and should have tried harder to obtain a larger reflector.^[39]

Unknown to Mayall, Lick observatory director William H. Wright and his predecessor, 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. Despite multiple attempts, 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 urged Sproul to have the Lick telescope use a mirror of that size. 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. The committee functioned primarily through correspondence. Mayall's first letter helped to convince Shane that 120 inches (3.0 m) 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, 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]

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

Kitt Peak National Observatory

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

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.

Aerial view of the Cerro Tololo Interamerican Observatory

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]}

Retirement

Mayall retired in 1971, at the age of 65,^[66][67] an event that was honored by a symposium held on his birthday, May 8.^[17][68] During his retirement, he continued to play an active role in many organizations, including the overview committee for Fermilab.^[17] He died on January 5, 1993 of complications caused by diabetes; his ashes were spread high on an empty ridge of Kitt Peak.^[2][69] Mayall was survived by his wife of 58 years, Kathleen Boxall,^[2][17] and their two children: Bruce I. Mayall and Pamela Ann Mayall.^[2][17]

Honors

Bibliography

See also

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

References

Cited sources

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