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NICHOLAS ULRICH MAYALL May 9, 1906-January 5, 1993 BY DONALD E. OSTERBROCK NICHOLAS U. MAYALL WAS born in the Midwest near the beginning of the twentieth century and died in Ari- zona near its anti. He was an outstanding observational astronomer of gaseous nebulae, globular clusters, en c! gal- axies. A product of the University of California, he joiner! the staff of its Lick Observatory even before he completer! his Ph.D. en c! remainec! a member for more than a quarter of a century, obtaining with its small reflecting telescope 11 , 1 ,~ O O excellent ctata on objects too faint for most astronomers to see. During WorIc! War II, he clic! important weapons clevel- opment work at Cambridge, Massachusetts, and then at Pasa- clena, California. He helpec! launch the Lick Observatory's large, new, postwar telescope and then left the University of California to become the director of the still very young Kilt Peak National Observatory. He built it up into an im- portant research institution, with large telescopes in both hemispheres, the National Optical Astronomy Observato- ries of tociay. LIFE HISTORY Mayall was born in Moline, Illinois, on May 9, 1906, the first of two sons. His father, Edwin L. Mayall, Sr., was an 189
90 B I O G RA P H I C A L EMOIRS engineer who worker! for a manufacturing firm in Illinois. His mother, Olive UIrich Mayall, although she clic! not go to college, hac! a visionary unclerstancling of higher education en c! set high stanciarcis for her two sons, Nicholas en c! Edwin, {r. The family mover! to the central valley of California some- time between 1907, when Edwin, {r., was born, en c! 1913, when Nick began first gracle at a small rural school near Modesto. By 1917 they hac! mover! to Stockton. Except for one year back in Peoria, Illinois (1918-19), they stayer! there through 1924, when Nick gracluatec! from high school. Some- time along the line, probably while Nick was in high school, his parents were clivorcecI. In his senior year at Stockton High School, Nick arranged for the science club, of which he was secretary, to visit Lick Observatory, atop 4,200-foot-high Mount Hamilton, near San Jose. He was allowed! to drive his father's auto en c! take a car full of boys up the wincling mountain roacI, at that time unsurfaced! flirt en c! gravel. It was his first sight of the observatory where he was to be a student en c! spenc! so much of his professional career. The visit inspirer! him to react all the astronomy books in the high school en c! local public libraries, but he hac! never thought of making as- tronomy his profession. EDUCATION In the fall of 1924 Mayall enterer! the University of Cali- fornia in Berkeley as a freshman in the College of Mining. He liver! with his mother in an apartment on Durant Av- enue en c! worker! in the stacks at the university library to earn the money they neeclec! to survive. Mayall was a goof! student, who ultimately was electec! to Phi Beta Kappa en c! Sigma Xi, but by the midterm examinations in the first semester of his sophomore year he was howling for poor marks in mineralogy en c! chemistry laboratory. The clean
NICHOLAS ULRICH MAYALL 191 caller! him in en c! fount! that Mayall was color-blincI. He conic! not see the subtle color changes in flame en c! beac! tests, nor in titrations en c! precipitations. His aciviser toIc! Mayall that there was nothing to do but change his major, a mining engineer hac! to be able to clo those tests to graclu O O ate. At this point Mayall cleciclec! that maybe astronomy was for him after all. He consultec! his mother, who urger! him to clo what interested him most but, whatever it was, to clo it well. First, he investigatec! carefully, asking several profes- sors in the Berkeley astronomy department if they were happy in their work en c! making a clecent living. Receiving affirmative answers, he transferred to the College of Letters en c! Science en c! majorec! in astronomy. This clic! not clelay his progress, for nearly all his freshman work hac! been in mathematics en c! basic physical sciences. He fount! he likes! astronomy very much en c! cleciclec! to go on to graduate work en c! a career as a research scientist. In 192S, when Mayall finisher! his unclergracluate work en c! receiver! his A.B., the University of California hac! the most outstanding graduate astronomy program in the country. All the courses were taught by the professors in the Berke- ley department on the campus, but many of the students clic! their thesis work on Mount Hamilton, uncler the tute- lage of a Lick astronomer who became a member of their thesis committee. The founder en c! long-time chairman of the Berkeley department, Armin 0. Leuschner, was an ex- pert on celestial mechanics. Most of the other faculty mem- bers in the department were his former students, selectee! much more for their teaching ability than their research qualifications. What research they did do was also in celes- tial mechanics, except for C. Donalc! Shane, another Berke- ley product who hac! clone his thesis on carbon stars at Lick en c! who taught all the astrophysics courses in the clepart
192 B I O G RA P H I C A L EMOIRS meet, unclergracluate or graduate. The graduate students were very well trainee! in the "theoretical astronomy" of that clay ( celestial mechanics), especially "Leuschner's methocI" for determining the orbit of a newly cliscoverec! comet or asteroic! from three observations of its position. Mayall received a teaching fellowship (making him equiva- lent to a teaching assistant of tociay, worth $600 a year then) for his first year as a graduate student, 1928-29. He enjoyoc! the course work, especially in astrophysics, en c! learner! to calculate orbits rapidity en c! accurately. In the summer of 192S, before beginning as a graduate student, Mayall worked as the gracler for an astronomy course taught in the Berke- ley summer session by Seth B. Nicholson of the Mount Wil- son Observatory staff. He was a Berkeley product himself, who in 1914 at Lick cliscoverec! Jupiter IX, a small faint moon of the giant planet. Its orbit became the subject for his 1915 Ph.D. thesis. Nicholson toIc! Mayall that there wouIc! be an opening for a computer (a job hell! by a human being at that time) at the Mount Wilson Observatory of- fices in Pasadena the following year. By then Mayall was tiring of course work, he applier! for the Mount Wilson position and got it. He worked there two years ~ ~ 929-3 ~ ), learning research by cloing it. His job was to assist Nicholson en c! several other staff members, inclucling Edwin Hubble, Alfrec! H. Joy, en c! Director Walter S. Aciams, by measuring and reducing their observational data. When Clyde Tombaugh cliscoverec! Pluto at Lowell Observatory in ~ 930, Mayall, working with Nicholson, clemonstratec! that Leuschner hac! taught them well. They user! the first preliminary orbit for the new planet, calculates! by Ernest CIare Bower en c! Fret! L. Whipple at Berkeley, to search along its early path for a direct photograph in the Mount Wilson collection that wouIc! provicle an early position of it. They fount! it, a very faint object in a crowclec! fielcI, on a plate taken in 1919, mea
NICHOLAS ULRICH MAYALL 193 surer! it, en c! quickly caTculatec! en c! publisher! the first cle- finitive orbit with an eccentricity. It shower! that Pluto was certainly a planet whose orbit crosser! that of Neptune. But Mayall manager! to get to Mount Wilson often himself, work- ing with the staff astronomers on all the telescopes en c! using most of them on his own as well. He became espe- cially close to Milton L. Humason en c! was inspirer! by Edwin Hubble. Mayall cleciclec! he wantec! to make his career in nebular spectroscopy en c! research. When he returnee! to Berkeley in the fall of 1931 to com- plete his graduate course work, Mayall hac! a Martin Kellogg Fellowship (worth $1,000 per year) en c! a prospective thesis topic, suggestec! by Hubble. It 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 (36-inch) reflector, on Mount Hamilton, to supplement the counts Hubble him- self was making with the 60-inch en c! 100-inch telescopes at Mount Wilson. Mayall clic! very well in his courses en c! went to Lick Observatory in the summer of 1932 to begin the main part of the observational work. He hac! learner! well from his Mount Wilson mentors en c! was an expert at ob- taining first-liass direct photographs with the ancient en c! tricky Crossley telescope. Mayall macle the counts on his own plates, after closely inspecting earlier ones taken by his predecessors at the instrument, Heber D. Curtis, Charles D. Perrine, en c! lames E. Keeler, the latter the seconc! cli- rector of Lick Observatory, who hac! put the Crossley into operating conclition en c! with it first cliscoverec! (at the turn of the century) the very large number of spiral "nebulae" in the universe. Mayall finisher! his thesis en c! receiver! his Ph.D. degree at the 1934 Berkeley commencement. Hubble praiser! his work, which was in fact excellent technically. However, the whole program, on which Hubble himself spent years, never
94 B I O G RA P H I C A L EMOIRS achiever! very significant results. It was flawed! by the lack of accurate magnitude stanciarcis for the faint galaxies at which it was aimec! en c! by the then-unrecognizec! very strong clus- tering tendency of galaxies. LICK OBSERVATORY Mayall's thesis Divisor, William H. Wright, a University of California graduate en c! a Lick Observatory staff member since 1897, was a nebular researcher en c! spectroscopist him- self en c! a great frienc! en c! admirer of Hubble. Mayall wan tee! to design en c! built! a small fast spectrograph, optimizer! for nebulae en c! galaxies, to use at the Crossley to make it com- petitive for at least some of the spectacular work that Humason en c! Hubble were then cloing with the larger tele- scopes at Mount Wilson. Wright en c! Joseph H. Moore, the heat! of the Lick stellar spectroscopy program, encouragec! Mayall to go ahead with the design and then had the spec- trograph built in the observatory shop. Though there was no opening on the staff for even the most junior astrono- mer, they kept Mayall at Lick as an observing assistant after he got his Ph.D. It was the same position he hell! for the final year of his thesis work en c! in reality allowed! him to devote most of his time to his own research. The job pair! very poorly, but the Great Depression was at its height (or in its depth), and there were few available alternatives, none J for Mayall, who was committee! to a research career with the spectrograph he hac! clesignecI. He hac! hoper! for a position at Mount Wilson, but there were no openings at all there because of the Depression. As he began his postdoctoral career at Lick, Mayall mar- riec! Kathleen (Kay) Boxall of Los Angeles on June 30, 1934. They met cluring his two years in Pasadena, according to family legencI, at a field! hockey game, probably at Tourna- ment Park, very near Caltech. Whether it was a mixer! game
NICHOLAS ULRICH MAYALL 195 or Mayall was a spectator was not reported. They mover! into a small apartment in the little astronomy village on the summit of Mount Hamilton, where all the astronomers livecI. One year later, on July I, 1935, Robert G. Aitken, the elclerly director of Lick Observatory, retired, en c! Wright succeeclec! him in the post. The two of them, en c! Moore, hac! manager! to keep Mayall en c! his goof! frienc! Arthur B. Wyse, who hac! also receiver! his Lick Ph.D. in 1934, on the staff, initially as observing assistants. Now as assistant as- tronomers they replacer! Aitken en c! Robert l. Trumpler, who mover! to Berkeley in 1935. Mayall began using his new nebular spectrograph at the CrossTey. Although it was not competitive with Humason's instrument on the much larger 100-inch telescope for stars or elliptical galaxies, with their condensed, relatively bright nuclei, the Lick spectrograph was actually faster for extenclecI, low-surface-brightness gaseous nebulae en c! irregular galax- ies. This was particularly the case in the ultraviolet, for Mayall, with Wright's strong encouragement, user! quartz en c! ultra- violet transmitting optics, in contrast to the Mount Wilson spectrographs with their heavy glass lenses en c! prisms. With it Mayall got the first really goof! spectrum of the Crab nebula. From it en c! the previously publisher! angular rate of expansion of the nebula, he was able to estimate its clis- tance. With this ciata, Mayall became the first to recognize en c! prove the Crab nebula to be the remnant of a super- nova observer! en c! recorclec! by Chinese astronomer-astrolo- gers in 1054, rather than an ordinary nova. He also fount! important new results on emission nebulae in the nearby spiral galaxy M 33 en c! various irregular galaxies en c! on the unexpected occurrence of forbiciclen emission lines of ion- izec! oxygen in the spectra of the nuclei of many galaxies, a sign of the frequent presence of ionized interstellar gas even in the centers of these objects. With Hubble's encour
96 B I O G RA P H I C A L EMOIRS agement Mayall measurer! spectroscopically the rotational velocities of several spiral galaxies. Wyse colIaboratec! with Mayall on several papers on the interpretation of the mea- surec! raclial velocities of the H II regions in M 31 en c! M 33 in terms of the rotation of these two especially nearby spi- ral galaxies, the gravitational field! that it impliecI, en c! hence the distribution of mass within them. They macle a goof! team, Wyse more theoretically inclined, Mayall an excep- tionally skillet! observer with the Crossley reflector he knew so well. His color blinciness stool! him in goof! steal! here, for along with it he apparently hac! much more acute sensi- tivity to very low light levels than most mortals. Certainly he conic! see on the slit en c! in the periscope eyepiece of his spectrograph objects that were too faint for most other as- tronomers who observer! with him, inclucling myself. Among the California graduate students who worker! with him in those early years at Lick, the closest to Mayall were Daniel M. Popper en c! Lawrence H. Aller (who finisher! his Ph.D. at Harvarc! but came back to Mount Hamilton to observe several times). They both acimirec! him greatly for his observational skills, his cleclication to astronomy, en c! his warm, friencITy personality. He was a goof! Divisor to them en c! a realistic one. {an H. Oort, the outstanding Dutch astronomer, colIabo- ratec! with l. l. L. Duyvenciak, an Oriental scholar, in estab- lishing the identity of the Crab nebula with the "new star" recorclec! by the Chinese a millennium ago. After HolIanc! was overrun by the Nazis early in World War II, Oort, by correspondence, suggested to Mayall further ancient sources, inclucling Semitic records, which might contain informa- tion. Mayall helped track them down at Berkeley and pub- lishec! the results in a joint paper with Oort. The MayalIs hac! two chilciren, Pamela en c! Bruce, who grew up on the mountain en c! attenclec! its one-room school.
NICHOLAS ULRICH MAYALL 197 When they graduated from eighth grade, they had to go away to boarding schools. Mayall took the hour-a-day job as postmaster on Mount Hamilton to help pay the associated costs. WORLD WAR II World War II abruptly put Mayall's research career on hold, just as he was getting established. Well before America entered the war both he and Wyse applied for Naval Re- serve commissions, to be called to duty as navigation in- structors if needed. Mayall was rejected, because his color blindness prevented him from passing the required physi- cal examination. In the fall of 1941 Wyse joined a wartime Navy antisubmarine technical project at San Diego as a ci- vilian scientist. He was killed in sea trials of a proposed new submarine detection system in June 1942 in a collision of two dirigibles over the Atlantic Ocean. He had been Mayall's close friend. Mayall, along with nearly everyone else who knew Wyse, expected that he would someday become direc- tor of Lick Observatory. Even before Wyse's death, Mayall accepted a position at the Radiation Laboratory in Cambridge, Massachusetts, to work on radar development. Gerald E. Kron (who recruited him) and Hamilton M. Offers, of the Lick staff, both single men, had begun working there before Pear! Harbor. Mayall worked on testing and calibrating the accuracy of the posi- tions of airplanes provided by the early radar systems, com- paring them with optical, visual, and photographic posi- tions. However, the Boston climate, changeable and extreme compared with the California weather to which Mayall was accustomed, caused him and his family many colds and illnesses and aggravated his arthritis and sciatica. He felt he could not make real contributions at the Radiation Labora- tory, dominated by electronic and antenna experts.
98 B I O G RA P H I C A L EMOIRS In micI-! 943 Mayall arranger! to transfer to the Mount Wilson Observatory offices in Pasadena, where several war- time Office of Scientific Research en c! Development projects concernec! with optics, aerial gunnery, bombing tactics, en c! aerial photography were uncler way. There, in the atmo- sphere of California en c! astronomy, Mayall's health was re- storecI. In one of the ironies of the war, he ate lunch tinily with the two German-born Mount Wilson Observatory staff members Ruclolph Minkowski, a naturalizes! American citi- zen who was working with him on the OSRD projects, en c! Walter Baacle, still a German national, who conic! not par- ticipate in or even know of the war work. Presumably, Mayall en c! Minkowski "buttoner! up their lips" (as the wartime posters urged them to do) and did not pass any military secrets to Baacle. His enemy alien status meant he was re- stricted to Los Angeles County, and, as practically the only member of the Mount Wilson staff not cloing any war work, Baacle hac! nearly unlimitec! use of the 100-inch telescope. Uncler the wartime brownout in Los Angeles, the night skies were unusually ciark, en c! Baacle was able to take direct pho- tographs of the nearby Andromeda galaxy, M 3l, and its companions, which shower! stars to a fainter level than he hac! been able to reach before. This observation was the final evidence in his great discovery of the "two stellar popu- lations," young stars en c! oicI. Mayall was on the scene in the late summer en c! fall of 1943 as Baacle clic! this work en c! cliscussec! it ciaily with him. Astronomical observations were not military secrets, en c! the enthusiastic Mayall kept the few elderly Lick astronomers still on the job at Mount Hamilton informed of Baade's epochal results. Mayall enjoyed the Mount Wilson Observatory atmosphere, especially when he was even allowed! to work with the 60- inch telescope for two nights cluring his Christmas vaca- tion! But he believer! that, owing to mismanagement in the
NICHOLAS ULRICH MAYALL 199 higher levels of the OSRD optical instruments division, he en c! the Mount Wilson group were not being given a chance to make a really effective contribution to the war effort. Hence, he welcomer! an opportunity to transfer in Febru- ary 1944 to the California Institute of Technology, whose big rocket development project was clearly providing im- mecliately effective weapons. Several other astronomers were working there, inclucling Kron, who hac! mover! there ear- lier, Horace W. Babcock, who clic! his Lick Ph.D. thesis un- cler Mayall's supervision, en c! John B. Irwin, a former Ber- keley en c! Lick graduate student. Mayall, who worker! on the Caltech campus en c! sometimes at the more open test- ing areas at Inyokern, in the Mojave Desert, soon macle himself a highly productive member of the project. He be- came an expert at high-speec! photography, necessary to stucly en c! unclerstanc! rocket trajectories en c! impacts. After the German surrender in the spring of 1945, Mayall was transferred to an ultrasecret group working on very-high- speec! photography for the atomic bomb project, in con- nection with the plutonium implosion weapon. He macle at least two trips to Los Alamos, one at about the time of the Trinity test, but he was not there for the firing. Probably he had briefed the Los Alamos high-speed photography group or cliscussec! some of their results with them. Mayall, a con- firmec! believer in security to the enc! of his life, steacifastly cleclinec! to discuss this aspect of his wartime career. Soon after the war enclecI, Mayall was releaser! from his post, en c! by October I, 1945, he was back in astronomical research at his belovec! Mount Hamilton. During his three years with the OSRD, Mayall hac! macle important contribu- tions to the war effort, particularly at Caltech and Inyokern. In aciclition, he hac! gotten out of the comfortable little worIc! of astronomy en c! hac! greatly broaclenec! his outlook on science, research, en c! leaclership. At the Racliation Labo
200 B I O G RA P H I C A L EMOIRS ratory and at Caltech, Mayall saw big science in action, in its wartime version, en c! he macle many contacts with physi- cists with whom he wouIc! interact frequently in his later years as director of Kitt Peak National Observatory. THE 120-INCH TELESCOPE During Woric! War II, Mayall playact an important role in determining the future of Lick Observatory. From the time he returnee! to Berkeley en c! Lick in 1931, after his two years as an assistant at Mount Wilson, he felt acutely the neec! for a larger telescope at Mount Hamilton. The Lick astronomers priclec! themselves on getting important results with their small, 36-inch CrossTey reflector, which hac! been dwarfed! by the Mount Wilson 60-inch since 190S, the Do- minion Astrophysical Observatory 72-inch since 1917, en c! the Mount Wilson 100-inch since 1919. Mayall became an expert observer with the Crossley, but he realizer! that it conic! never really compete with a telescope with three times its diameter, nine times its collecting area. It wouic! be even worse when the Palomar 200-inch came into use. Mayall en c! the other younger Lick faculty members believer! that the older astronomers, Wright and Moore, were too com- mittec! to the small telescopes ant! shouIc! have worker! harcler to get a larger reflector for Mount Hamilton. Wright was proud of what he had accomplished with the CrossTey and tended to scoff at the big-telescope mystique, but actually behind the scenes he and Aitken, his predecessor, had tried hard to raise the money for a larger reflector from private sources en c! also to persuacle University of California Presi- clent Robert G. Sproul to put it in the buciget. They failer! in each attempt, largely because of the Great Depression. However, unknown to Mayall, Sproul changer! his mine! in 1942, after his first choice for a director to succeec! Wright, Paul W. Merrill of Mount Wilson Observatory, clecTinec! to
NICHOLAS ULRICH MAYALL 20 leave the big telescopes even for the directorship of the University of California's famous research institution. Sprout, shaken by Merrill's refusal, toIc! the regents that they must raise the money somehow after the war enclecI. At the same time, he either secretly appointee! Shane, by then chairman of the Berkeley Astronomical Department, as postwar clirec- tor of Lick, or promiser! him the post. In September 1944 news of the planned big postwar tele- scope but not of the new director surfacer! in the Univer- sity of CaTifornia's budget proposals. Moore, by then the interim wartime director, en c! Wright, seventy-two years oIc! but still very much on the scene as a retiree! astronomer recallec! to service, thought of it as an 85-inch or 90-inch telescope, the largest instrument that they believer! conic! be built for the funcis specifier! in Sproul's buciget pro- posal. Mayall en c! the other young Lick astronomers en c! former graduate students now in Pasadena, all of whom longer! to return to Mount Hamilton en c! who cliscussec! frequently everything that happened there, believed that Moore en c! Wright were out of touch with the real neecis of astronomy. EmboIclenec! by the wartime emphasis on youth and on cutting through red tape to get results, Mayall re- solvec! to go straight to the president of the university him- self. He wrote Sproul, asking for an appointment to see him on one of his regular monthly visits to the University of California at Los Angeles campus. Kron also signet! the letter, in which they said that, "as younger members of the ELick] staff, who hope to use the instrument," they wished to discuss "what kinc! of telescope" the University of Califor- nia shouIc! built! when the war enclecI. Sproul welcomer! them to his Los Angeles office in December 1944. Mayall clic! most of the talking. He emphasizec! the new! for a telescope bigger than a 90-inch. In Pasadena he hac! seen the 120-inch glass clisk originally intenclec! for testing the
202 B I O G RA P H I C A L EMOIRS 200-inch Palomar mirror, then nearly finisher! in the Caltech optical shop. He urger! Sprout to make the Lick reflector that large. To Mayall and Kron's surprise, Sprout quickly assenter! en c! in turn urger! them to keep up the pressure on "the old men." In early 1945 Sprout appointee! a committee, chairec! by Shane, then on leave at Los Alamos as assistant director for scientific personnel, to plan the postwar Lick telescope. He also appointee! Moore en c! Mayall to the committee, as well as Mount Wilson Observatory Director Walter S. Aciams en c! Caltech physicist Ira S. Bowen, who wouIc! succeec! Aciams en c! become the first director of Mount Wilson en c! Palomar Observatories at the war's anti. The committee worker! mostly by correspondence, en c! Mayall's first letter helpec! to per- suacle Shane that it was reasonable to hope for a 120-inch rather than settle for a 90-inch, as he hac! earlier thought. Mayall, on the scene in Pasadena, was invaluable in provicI- ing liaison between the strong telescope group there en c! Shane, whose expertise was much more in teaching en c! university administration than in instrument design. Aciams en c! John A. Anderson, executive officer of the 200-inch project, macle their drawings, plans, en c! experience freely available to the California astronomers. Mayall was present at the one actual meeting of the committee, in Pasadena on March 6, 1945, when Shane conic! get away from Los Alamos briefly. On that clay the committee macle all the basic decisions for what eventually became the Lick 120- inch reflector. Shane en c! Mayall went on to Mount Hamilton the next clay en c! there, with Moore (who hac! not been able to get to Pasadena) and Wright, picked out the spot where the telescope would be erected. After the war Shane guided the 120-inch project through the university en c! helpec! Sproul sell it to the legislators en c! the governor. Caltech macle its clisk available at cost,
NICHOLAS ULRICH MAYALL 203 which bypasses! the clelay that ordering a new one wouic! have caused. Mayall, as the most experienced big telescope user on the Lick faculty, who often went to Mount Wilson en c! later even to Palomar to observe with Baacle, Minkowski, en c! Humason, macle many suggestions that were incorpo- ratec! into the Lick reflector. It was safe, souncI, conserva- tive, en c! productive his style exactly. POSTWAR LICK RESEARCH The 120-inch telescope was years in the burbling. Mean- while, Mayall worker! actively on research with the Crossley reflector. He began obtaining the integrated spectra of gIobu- lar clusters with his fast spectrograph well before the war. Now he finisher! this work en c! publisher! the results the raclial velocities of the first fifty clusters. The result was important in proving that the system of globular clusters shares only slightly in the galactic rotation exhibitec! by the flattener! system of young stars en c! interstellar matter in the Milky Way. This work, like all of Mayall's, was very well suites! to his small telescope en c! fast spectrograph, opti- mizec! for extenclecI, low-surface-brightness nebulae, galax- ies, en c! clusters. Much of Mayall's best work was done in collaboration with or at the suggestion of his friends en c! mentors at Mount Wilson Observatory. Although he still idolized Hubble, who hac! been on leave as director of the Army's Ballistics Research Laboratory at Aberdeen, MarylancI, for the clura- tion of the war, by the time the 200-inch telescope went into operation in 1948 the great observational cosmologist was tires! en c! ill. He sufferer! a heart attack in 1949, never fully recovered, en c! cliec! in 1953. Baacle hac! become Mayall's chief source of inspiration cluring WorIc! War II. He wrote frequently to his younger frienc! at Mount Hamilton, en c! they hac! Tong discussions at the informal Lick-Mount Wil
204 B I O G RA P H I C A L EMOIRS son en c! Palomar nebular research conferences that Shane en c! Bowen arranged. With Baacle's continues! encourage- ment en c! acivice, Mayall carrier! out a long, important pro- gram of spectroscopy of the H II regions in the spiral arms of M 3l, to better define its rotation curve. One very important paper Mayall published in observa- tional cosmology, with Humason en c! the young Allan Santiago as coauthors, was a catalog of the Lick, Mount Wilson, en c! Palomar recishifts of galaxies. It container! the recishifts of more than 800 galaxies observer! over the years from 1935 to 1955. Humason proviclec! the ciata on the ellipticals en c! distant spirals for which the 100-inch en c! 200-inch tele- scopes en c! their spectrographs were so well suited, Mayall for the irregulars en c! nearer spirals, en c! Santiago proviclec! most of the magnitudes. He was also chiefly responsible for the discussion in terms of the velocity-clistance relationship. This paper enormously strengthener! the observational evi- clence for a linear velocity-clistance relationship. The value they cleterminec! for the Hubble constant, IS0 km/sec/Mpc was a step along the way from the outstanding observa- tional cosmologist's early value of 530 km/sec/Mpc to the currently acceptec! values of 50 to 100 km/sec/Mpc. The great expert on spectral classification of stars, Will- iam W. Morgan, worker! with Mayall en c! his collection of galaxy spectra during a visit to Lick. They published a joint paper on the results, a spectral classification of galaxies that shower! many of the population en c! heavy-element abun- ciance differences between spiral en c! elliptical galaxies, much later made quantitative by detailed CCD spectrophotom- etry. Mayall en c! Kron, again with the very active encour agement of Baacle, collaborates! on measuring the colors of globular clusters in our own Galaxy en c! in M 31 en c! its companions, for information on interstellar extinction en c! the stellar populations of these clusters.
NICHOLAS ULRICH MAYALL 205 From the enc! of Woric! War II, Mayall was the editor of all the Lick Observatory scientific publications en c! hence a member of the eclitorial boars! of the Astrophysicat fournat. He clevotec! consiclerable effort to this task en c! greatly im- provec! the clarity en c! accuracy of presentation of several of his colleagues' papers. As the ~ 20-inch telescope approached completion on Mount Hamilton, Mayall was responsible for taking the test exposures that shower! how close the primary mirror was to the correct form en c! what aciclitional figuring was neces- sary to bring it to the final icleal paraboloicI. On this project he worker! with Stanislavs Vasilevskis, who measurer! the plates en c! reclucec! the numerical results to quantify the form of the mirror. In ~ 958 with the telescope still not completecI, Shane stepper! clown as director. Albert E. WhitforcI, his successor, was brought from the University of Wisconsin to finish the task en c! put the ~ 20-inch into operation. The opticians finally figurer! the mirror correctly, as the test plate Mayall took on June 17, 1959, confirmed. Then the mirror conic! be aluminized and the auxiliary instruments installed. By early 1960 the 120-inch was in regular operation. Mayall began taking direct exposures of nebulae en c! galaxies at the prime focus, but only a few months later, in September 1960, he left Lick Observatory en c! Mount Hamilton. KITT PEAK NATIONAL OBSERVATORY Mayall left the University of California, where over a span of more than a quarter of a century he hac! been uncler- gracluate, graduate student, en c! assistant en c! hell! every rank from assistant astronomer to astronomer, to become the seconc! director of Kilt Peak National Observatory. The national observatory concept hac! only become a reality a few years before. Uncler the financial sponsorship of the
206 B I O G RA P H I C A L EMOIRS National Science Foundation, a group of universities orga- nizec! a consortium, Associatec! Universities for Research in Astronomy, to built! en c! operate a research observatory for all American astronomers to use. The first director. Aden B. Meinel, locater! the site, Kitt Peak, a 7,000-foot mountain near Tucson, Arizona. He selectee! en c! recruitec! the first staff members en c! built the first telescopes. But in the spring of 1960, as the Kitt Peak 84-inch reflector was completec! en c! cleclicatecI, the AURA Boarc! of Directors cleciclec! that Meine! was not the person to manage it. He resigned, en c! the boars! namer! Mayall to succeec! him. Shane, who repre- sentec! the University of California on the AURA boars! en c! was its president at that time, playact the major role in per- suacling him to take the job. Mayall hac! never hac! any previous administrative experi- ence, but he was an excellent choice for the post. Then fifty-four years oIcI, he was really for a change, and, after only a brief hesitation, he acceptec! the proferrec! appoint- ment. He gave Kitt Peak instant creclibility, in a way that Meinel, a postwar Ph.D., en c! the few young staff members he hac! assemblec! conic! not clot Several of the Lick, Mount Wilson, en c! Palomar astronomers, comfortable with the iclea of an elite few having the largest telescopes in the worIc! at their clisposal, hac! scoffer! at the concept of an observatory for everyone (although Bowen, Shane, en c! Whitforc! all supporter! the project strongly). But no one conic! scoff at Mayall, one of the most respected research astronomers in America. A member of the National Academy of Sciences since 1949 en c! chairman of its astronomy section, former president of the Astronomical Society of the Pacific, en c! president of the International Astronomical Union Com- mission on Extragalactic Nebulae, he clearly belonged. He conic! recruit new staff members who wouIc! come firm in
NICHOLAS ULRICH MAYALL 207 the knowlecige that he wouic! be there for years en c! that the national observatory was there to stay. In his early years Mayall receiver! frequent acivice from Shane, but he quickly picket! up the skills neeclec! to direct Kitt Peak National Observatory. He was particularly effec- tive in hancIling its external relations, with NSF aciministra tors, university vice-presiclents en c! business managers, en c! Arizona en c! government officials. The 1960s were the post- sputnik era in American science. The country was prosper- ous en c! eager to support research. Mayall saw to it that Kitt Peak got its share of the available funcling. He knew well all the astronomers who represented their various universities on the AURA boars! en c! conic! work effectively with them. Mayall clelegatec! almost all the responsibility for clesign- ing new instruments en c! operating the telescopes to the younger staff astronomers. Some met the challenge, others clic! not. As the staff grew, Mayall brought in some first-rate scientists who were willing to give their time en c! effort to make it possible for short-term visitors from all over the country to get important scientific results. Everyone who worker! uncler Mayall at Kitt Peak consiclerec! him kinc! en c! gentle, en c! some thought that he was a little too gentle- with others. One administrator, not a scientist, was a con- tinual source of problems, but he was useful, too, en c! Mayall never got ric! of him. As director, Mayall presided over the building of the 4- meter reflector, Kitt Peak's largest telescope. It was a huge team-engineering project that hac! been planner! even be- fore he came on board. Some of his former Lick colleagues en c! students were surpriser! en c! somewhat clisappointec! that he never began a research program of his own with the big Kitt Peak reflector, but he felt that he had too many other responsibilities that hac! to come first. Mayall was much more personally involves! in the expan
208 B I O G RA P H I C A L EMOIRS sion of the national observatory to the southern hemisphere' in the Chile project that eventually became Cerro Tololo Interamerican Observatory. He en c! Shane went to Chile two months after he acceptec! the directorship en c! scouter! the prospective sites. Mayall reporter! that he favorer! the one that was subsequently chosen, on Cerro Tololo. He strongly believer! in the southern hemisphere observatory, as he clemonstratec! by his frequent trips to Chile en c! al- most tinily raclio en c! telex contacts with the CTIO director, Victor Blanco. Mayall helpec! it grow, en c! its 4-meter reflec- tor was well uncler way when he retiree! in 1971, at the age of sixty-five. Mayall's retirement was market! by a scientific symposium, hell! in Tucson, at which Morgan, Minkowski, Santiago, en c! Margaret Burbicige were the invites! speakers. He en c! his wife remainec! in Tucson, and, when the Kilt Peak 4-meter reflector was completec! en c! cleclicatec! in 1973, it was namer! the Mayall telescope for him. He was present for its "first light" on February 27 of that year. The telescope was in full operation by 1974, as was the Cerro Tololo 4-meter tele- scope the following year. Mayall hac! liver! to see his work bear fruit. In retirement he corresponclec! frequently with Shane en c! Frank K. Ecimoncison, the long-time AURA rep- resentative of Indiana University who was one of the strongest early proponents of the cooperative or national observatory concept. Mayall kept in touch with the observa- tory en c! his many friends on its staff. He hac! sufferer! from diabetes for thirty years en c! cliec! at his home in Tucson on January 5, 1993. In summary, Mayall was an outstanding observational as- tronomer. At Lick Observatory he macle many contribu- tions to our knowledge of gaseous nebulae, supernovae, the motions within spiral galaxies, en c! the recishifts of the galaxies in the universe. In eleven years as director of Kilt
NICHOLAS ULRICH MAYALL 209 Peak National Observatory, he built it en c! Cerro Tololo Interamerican Observatory into first-rate research observa- tories, with worIcI-cIass telescopes. Throughout his career he remainec! a kincI, considerate person who was respected en c! acimirec! by all who worker! for him. THIS BlOG~PHICAL MEMOIR IS based largely on the written record of Mayall's research, given in his published scientific work, and of his other accomplishments and his life, drawn from hundreds of letters to, from, and about him in the Mary Lea Shane Archives of the Lick Observatory, going back to the 1924 letter that he wrote as secretary of the Stockton High School science club. These include a great many letters from his own personal scientific correspondence, which he presented to the archives. Some of the material on his student days is from his autobiographical chapter in a University of California centennial volume.) I knew Mayall personally since 1957, had many conversations with him in his later years about his scien- tific life, and interviewed him extensively in 1987, just before the Lick Observatory centennial. In addition, I received letters and messages from many of Mayall's former colleagues at Lick, Kitt Peak, and the wartime Caltech project, giving their reminiscences of him. I am greatly indebted to all of them, as I am to Kay and Bruce Mayall, who kindly provided additional information, particularly on this great astronomer's early life. NOTE 1. Nicholas U. Mayall. In There Was Light, Autobiography of a Uni- versity: Berkeley: 1868-1968, ed. I. Stone, pp. 107-19. Garden City: Doubleday & Co., 1970.
210 B I O G RA P H I C A L S E L E C T E D EMOIRS B I B L I O G RAP H Y 1928 With H. G. Miles and F. L. Whipple. Elements and ephemeris of comet k 1927 (Skjellerup). Lick Obs. Bull. 13:120-22. 1930 With S. B. Nicholson. The probable value of the mass of Pluto. Publ. Astron. Soc. Pac. 42:350-51. 1931 With S. B. Nicholson. Positions, orbit, and mass of Pluto. Astrophys. 7. 73:1-12. Recent novae in the great spiral nebula in Andromeda (M 31~. Publ. Astron. Soc. Pac. 43:217-20. 1934 A study of the distribution of extra-galactic nebulae based on plates taken with the Crossley reflector. Lick Obs. Bull. 16:177-98. The spectrum of the spiral nebula NGC 4151. Publ. Astron. Soc. Pac. 46:134-38. 1935 An extra-galactic object three degrees from the plane of the galaxy. Publ. Astron. Soc. Pac. 47:317-18. 1936 A low dispersion UV glass spectrograph for the Crossley reflector. Publ. Astron. Soc. Pac. 48:14-18. 1937 The spectrum of the Crab nebula in Taurus. Publ. Astron. Soc. Pac. 49:101-5. 1939 The Crab nebula, a probable supernova. Astron. Soc. Pac. Leaflet 3:145-54.
NICHOLAS ULRICH MAYALL 211 With L. H. Aller. Emission nebulosities in the spiral nebula Messier 33. Publ. Astron. Soc. Pac. 51:112-14. The occurrence of X3727 tO II] in the spectra of extragalactic nebulae. Lick Obs. Bull. 19:33-39. 1940 With L. H. Aller. The rotation of the spiral nebula Messier 33. Publ. Astron. Soc. Pac. 52:278. With T. H. Moore and T. F. Chappell. Astronomical Photographs Taken at the Lick Observatory. Mount Hamilton: Lick Observatory. 1941 With A. B. Wyse. Increased speed of two Lick Observatory spectro- graphs treated with non-reflecting films. Publ. Astron. Soc. Pac. 53: 120-22. The radial velocity of IC 10. Publ. Astron. Soc. Pac. 53:122-24. With E. Hubble. Direction of rotation of spiral nebulae. Science 93:434. 1942 With L. H. Aller. The rotation of the spiral nebula Messier 33. Astrophys. f. 95 :5-23. With A. B. Wyse. Distribution of mass in the spiral nebulae Messier 31 and Messier 33. Astrophys. f. 95:24-43. With T. H. Oort. Further data bearing on the identification of the Crab nebula with the supernova of 1054 A.D. Part II. The astro- nomical aspects. Publ. Astron. Soc. Pac. 54:95-104. 1946 The radial velocities of fifty globular star clusters. Astrophys. f. 104:290- 323. 1951 With W. Baade. Distribution and motions of gaseous masses in spi- rals. In Problems of Cosmical Aerodynamics: Proceedings of the Sympo- sium on the Motion of Gaseous Masses of Cosmical Dimensions Held at Paris, August 16-19, 1949, pp. 165-84. Dayton: Central Air Docu- ments Office. Comparison of rotational motions observed in the spirals M 31 and M 33 and in the Galaxy. Publ. Obs. Univ. Michigan 10:19-24.
212 BIOGRAPHICAL MEMOIRS 1956 With M. L. Humason and A. R. Sandage. Redshifts and magnitudes of extragalactic nebulae. Astron. f. 61:97-162. 1957 With W. W. Morgan. A spectral classification of galaxies. Publ. Astron. Soc. Pac. 69:291-303. 1960 With S. Vasilevskis. Quantitative tests of the Lick Observatory 120- inch mirror. Astron. f. 65: 304-17. With G. E. Kron. Photoelectric photometry of galactic and extraga- lactic star clusters. Astron. f. 65:581-620. 1962 The story of the Crab nebula. Science 137:91-102. With A. de Vaucouleurs. Redshifts of 92 galaxies. Astron. f. 67:363- 69. 1970 With P.-O. Lindblad. Mean rotational velocities of 56 galaxies. Astron. Astrophys. 8: 364-74.
