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that ¡nd- onts THE PRESENT POSITION new IN GROUND-BASED ASTRONOI,TT lmy ìent port ents ces- It is clear that ground-based astronomy has spread before it a wealth of inviting prospects. Questions of the most fundamental nature regarding med the structüe and evolutionary history of the universe can be asked with DOt reasonable hope of obtaining answers. But on one frontier after another uch the growth of knowledge is limited because we need far more extensive oce. obse¡vational data than we now have. rbe What new facilities are needed to exploit the opportunities? In arriving refft at a recommended program, the Panel has conside¡ed the existing facilities, oce. and has reviewed how they came into being and were brought to their ugh present state of operating eficíency. It has compared the technical capabil- tds, ities of existing proven telescopes with the requirements set by the observa- )my tional tasks now clearly foreseen, It has also considered a projection of astronomical manpower over the next ten years, to keep the facilities and the number of observing outlets ín step with the demands of a growing body of researchers, and yet not outrun the expected supply of experienced instru- mentalists and observers needed to build and operate t-he new major installa- tions proposed. The Panel presents here its evaluations of tìe present posi- tion as a background for the recommendations tÏat follow in Sections III and IV. EORET IC AL AST ROP HY SIC TH S Before éxtensive new facilities are recommended, it is necessary to ínquire whether progress in understanding the universe is not as dependent on interpretâtion of old observations in the light of known physical laws, and on the new ideas that may thus come from theoretical astrophysicists, as it is on accumulation of still more observations. In the earþ decades of the 20th century, when the highly successful mountain-top observatories in tle western United States were exploring the virgin ffelds laid open by the great new telescopes, it was perhaps tme that not enough time was spent t3 Copyright © National Academy of Sciences. All rights reserved.

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on relating observaüons to theo¡etical lmowledge, The interpretations were not long in coming, but they came mainly from elsewhere. The founda- tions of modern theoretical ashophysics-theories of stellar atmospheres, the internal constitution of tlle stars, and cosmolog¡ for example-wãe hid in Europe, where cloudy skies anil small telescopes discouraged rapid develop- ment of observational astronomy. The Panel believes that any imbalance that may once have existed in this coultry has long since been co¡¡ected. At many universities in the United States tlere are groups of mature practitioners of theoretical astro- physics. Graduate schools give every young astronomer ín training a basíc grounding in the subiect, and at certain centers a number of studànts pre. pare for caree¡s in that field. Physical scientists trained in neighboring ûelds have become interested in astronomy and have made maior theoretica-i conkibutions to problems of thermonuclear energy soutces, to stellar evolu- tion, and to the radiation physics of radio sources, for example. Another desirable development has been the near disappearance of t}re separation between observationalists and theo¡ists. euite a number of U.S. astronomers are adept in both roles, and a balance in the numbers of spè- cialists of the two Çpes is maintained in most university graduate depart- ments. Through Irequent visitation and extended sojoìlrns at maior centets, the pure theoretical âshophysicists maintain fairly continuous contact with . :,1 the latest observational results, and there is immediate feedback of their ideas into proposed new observations. The Panel concludes that progress in observational astronomy is not idealimited. The limitation is still well on the side of obsewations, which come much more slowly than the flashes of insight that may be their initial ilspiration. While the Panel has concentrated its attention on the facilities needed to accelerate the acquisition of new observatíonal data about tÏe universe, it also recognizes the great importance of a continuing buildup of strength on the theo¡etical side. OPTICAL ASTRONOMY Present Domínant Position of the UníteiL States The position of Ieadership that thd United States enjoys in optical astronomy has been won as a direct result of its superior observing facilities. The event of greatest hístoric signiffcance was the building of the S6-inch refractor T4 Copyright © National Academy of Sciences. All rights reserved.

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at Lick Observatoïy on Mount Hamilton in the 1880's. This was the ffrst rtions permanently occupíed mountain observatory anywhere, anil quickly demon- unda- itt"ted t¡" advantages of such a site' The greât success of tle 36-inch tìe s, Crossley reflector at Lick Observatory a few years later leil naturaþ to ricl in tle perfecting of the large modern reflecting telescope, with all its advan- 'elop- tages for askophysical research. The founding of the Mount Wilson Ob- seivatory witl its 60-inch reflector, completed in 1908, and its 100-inch in :ed in 1918, was perhaps the decisive step towaril achieving leatlership. It was n the not entirely a matter of size and superior atmospheric conditions, however. astlo- The insistence of tle builders of all these pioneering telescopes on the high- basic est sta¡dards of optical and mechanical performance also contributed to ¡ pre: their spectacular success. The McDonald 82-inch telescope in West Texas oring in 1939, the giant 200-inch reflector on Palomar Mou¡rtain in 1949, and the etical 120-inch reflàctor at Lick Observatory in 1959 complete tìe list of tle rvolu- telescopes that have continued ttre tradition. All save the last were private grftr; th" 120-inch was ffnanced by tax monies of the State of California. rf the Íhese great telescopes are the peculiar American contribution to the devel- : U.S. opment of asbonomy. Inshuments like them are so essential to astronomers I spe- tlat nerv large telescopes are being planned in other parts of tÏe world. )part- À 104-inch reflector at the Crimean Observatory in the U.S.S.R. is iust get- nters, ting its auxiliary instruments, and a 237-ínch for a mountain site in the with U.S.S.n. is being planned. A 150-inch reflector for the Southem Hemisphere their is beíng planned by a group of European countries, and anottrer one of similar size for t}re Southern Hemisphere is being discussed by British s not Commonwealth nations. The momentum of the .{merican observatories will vhich not be quícHy overcome, but inevitable continuation of a position of leader- ¡itial ship should not be assumedl, leded i¡else, Thø Limìting Fa.ctor for Future Success rngth \ryith these excellent instruments in thè good-climate areas of tÏe western United States, what limits more rapid progress on the unsolved prob- lems already opened up? The Panel believes that it is not a lack of a unifying tleoretical concept or of new ideas, as explained earlier; not is it the lack of a proper number of skilled and imaginative observational âstronomers, It is not tÏe need to wait for crucial bits of data from space telescopes, helpful as these may be in certain cases. Neither is it delay in the con- nomy struction of a larger telescope than any yet made to get pâst an all-important event threshold of information. The limíting factor is, rather, simply the ertremelg actor t5 Copyright © National Academy of Sciences. All rights reserved.

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smnll m.rmber ol telescopes of ad.equnte siza in d.ark-skg Incatians and, úrc l consequent slow accumulation of urgentþ needed observational data. Only : a handful of ast¡onomers can now be engaged in a sustaineil attack on fron- tier problems at any one time. This dilemma arises because astronomical soulces are so faint tlat tele- scopes of the largest size are required for at least part of most problems. If we compute tle output capacity of all telescopes with adequate light- collecting area now in operation any'rvherg and compare this with the crucial I problems requiring certain numbers of photon-hours for their solution, we immediately perceive that our present instrumental facilities are entirely inadequate to meet the astronomical demand. Thus data precious to the advance of astrophysics are presently denied us. Only two existing telescopes are adequate for pushing current frontier problems to the observational limit. These are the Lick 120-inch and the Palomar 200-inch reflectors. (The 100-inch telescope on Mount Wilson has lost efiectiveness because of the light from nearby metropolitan areas.) These two telescopes do not begin to satisfy the requirements of mid-2Oth century astronomy. Experience over the past 20 years at the McDonald, Lick, Mount Wílson, and Palomar Observatories, shows that the most effi- cient exploitation of large telescopes requires carrying on several programs at once-work on faint obiects at the photomehic limit during the dark of tle moon, and spectroscopic work during moonlight. There is, however, an optimum number of perhaps 10 long-term problems that can be handled at any one time-giving each of them about 35 nights a year. Even then, such problems as t-he distance scale of the udverse, where cepheid variables must be found and measured. in galaxies, require.two to four years to com- plete at tlis rate, because of the large number of plates required. This means that 10 to 15 stafi astlonomers per major telescope is all that can be efiective. With onþ two major frontier telescopes operating, this means that no more than two or th¡ee astronomers in tTe entire worlil now have the opportunity to work on the most excitíng problems in any given ûeld. Competition and the obviously needed opportunity to check results are lacking. The problem, serious enough from the standpoint of progress, is even more serious in another respect: it squeezes out of research life at the frontier top-notch men who, by accident, are not among the fortunate staff members of big observatoríes. This is an extremely unilesirable situa- tion from many points of view. The problem can be, and is, documented every month by the adminis- trations of both Lick and Mount Wilson-Palomar, where meritorious projects 16 r-_ Copyright © National Academy of Sciences. All rights reserved.

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bv competent "outsicle" astronomers must be fumed down time after time il the fár hck of guest-investigator time at tbe telescopes' Ooly The establishment of the Kitt Peak National Observatory will begin to fron- ease the problem, but it is so acute that tÏe establishment of only one more 50-inch) is ot a sufficient answer' This is partþ -rio, t"i"r"op" (the 1be the only non-private instnment available to the tele- : because Kitt Þeak will n ,lems. more thnn 700 obsørcer canÅ,íilntes' ( Neither the Lick nor tle Mount Wil- IiCht- instítutions, ancl ,on arrd Pulomar Observatories are federally supportetl rucial thei¡ instruments are not generally available' ) If the yearþ assigned observ- n, we ing ,i*" on any large telescope is cut below 15 niqhts p3r proiect, no real tirely mã¡or problem'can be completed successfully in less,than three or four o the .,""r.. *hi"h is extremeþ long by modern standarils' There will, of course, L" i"* spectacular onå-shoi discoveries made with only a few nights, but rntier th" "follo*-ìp of these leads, so essential in the orclerly, progressive advance tl the of astronomy, will be missing. /ilson The inádeq-uacy of the existing large telescopes for the difficult prob- :eas,) lems involving fãínt sources would be even more acute if telescopes of lesser i-20th size could ,to-'t b" used to câlry the considerable fraction of the needed rnald, observations that do not demanil such geat light-gathering power' Tele- t efi- scopes of intermediate size can perforrn all the standard- observational tasks ms at ove-r most of the brightness range covered by obiects of a given class' For ,i thu some types of measrirement, toãh ut the study of nebulae, there is almost )f, an no loss of efficiency in going to a quite motlest telescqpe' ndled of the most productive use of Recent astronãmy it t"pl"t" *ith then, "*amples telescopes of small and intermediate size. Examples are: (1) photoelectric iables photometry of hundreds of sta¡ clusters to iletermi¡e color-magnituile dia- com- g."-., (2j the study of the rotation of galaxies from- spectrographic r-adial This ielocities, (S) spectroscopic studies of physical conditions and abundance an be ratios in gàsåous nebdaã, (4) the study of intrinsic variablg stars a¡d neans eclipsing iinaries, ( 5 ) narrow-band ûlter photometry for determining have lumlnosity and chemical composition of stars, and (6J obiective prism ûeld. suruey, fó, the discovery of peculiar emission obÍects and t-he iilentiffcation s are of stars of a particular class. gress, Interest L these valuable lines of research has maintaineil a steady ife at pressure on telescopes of small ancl intermediate size, which has been unate ànly pa*ly relieved b'y the facilities alreacly completecl at the Kitt Peak situa- Ñ"íi-"t óbservatory. The inadequacy so strongly felt at the largest tele- scopes is equally critical all along the line, and plans to bolster observing ninis- poiu, by U"lai"g new telescopeì must give attention to the whole range oiects t7 Copyright © National Academy of Sciences. All rights reserved.

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of sizes in order to provide an eficient set of observing tools tailored to the varied obsewational needs of the astronomical community. RADIO ASTRONOMY PÍesent Posítiøn of the United States The United States now has an impressive group of major radio telescopes; contrary to the situation in optical astronomy, however, it can not be said that the Àmerican position is dominant. The ûrst line of American tele- scopes, all constructed in the recent past, includes three large telescopes: the 1,000-foot ffxed-mirror irìstuument at .,{recibo, Puerto Rico, the 300-foot paraboloid at the National Radio Astronomy Observatory (NRÀO), and the 600-foot cylindrical paraboloid of the Universíty of lllinois; the latter two are tuansit instruments. Then there are the two-element interfetometers at the California Institute of Technology anil NRAO, and the soon-to-be- completed, 140-foot, fuþ steerable radio telescope at NRAO. As power- ful as these i¡strûments are, they are exceeded in capability (in ways to be discussed later ) by such foreign instuuments âs the 2l0-foot telescope in Australía, tÏe 22-meter millimeter-wave telescope near Moscow, and ttre large cross-q4)e arrays nearing completion near Sydney and Moscow. A {urther development that will outrank American telescopes in capability is tlre proposed high-resolution instrument to be constructed by the Benelux nations. for Hàgþ Angulnr Resolutian NaeiL Even more important than the capabilities of U. S. railio telescopes rela- tive to tlose in other parts of tlre world, however, is the capaciÇ of these telescopes to provide the key data requirecl by the central problems now confronting radio astronomers. In one ffeld of research after another, existing and projected telescopes fall short in one all-important respect: angular resolution. The reason for the exceedíngly |uzzy view o{ the radio sþ given by these instruments is that they are not large enough, measured in units of the wavelength of the receíved radiation, to narrow the instru- mental diflraction patter:n to efiective levels. It must be remembe¡eil that radio telescopes difier f¡om optical telescopes in their ability to resolve ûne detail because the wavelengths of the radio waves are as much as a million times longer tlian the wavelength of the optical railiation. t8 t_ s Copyright © National Academy of Sciences. All rights reserved.

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opes; , said tele- opes: )-foot , and r two retels o-be- lwef- ys to scope , ?nd scow. .bility 7 ¡elux The peculiar galary tr482 in hlJd,rogen light. Thø frLaments eúend,íng upøard and Fíguîe are composeð. ol nateîial tlxrolÙn oltt bg an erplosion in tlle nuclear regioñ of the dotL;nuaard, galaq about I milliþn geo.Ìs aga. rela- these ; now other, rpect: radio !sured nsfuu- I ttrat 'e ûne lillion É. Copyright © National Academy of Sciences. All rights reserved.

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r Fígure 2 The spiúL galaxg M31, uíth íts tüo compaìnioß, as photogruphed þith øn optícøl telescope giDíng a rcsolu- tion of 1 second, of arc- iJ- Copyright © National Academy of Sciences. All rights reserved.

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The galarg M31 øs ít u;ould, appeu to a lelesaope 4 ¡esoluÍían ol 34' The gaünV M37 Fìgure seen tD¡th 12, resohttìon- o.s L íts tØo aompaníons, ,ope eíþíng ø rcsolu 5 galatg M31 as seen aith 3' resolut¡on- 6 Th.e The galary M37 as seen @ìth ft Figurc rcsolutìon. Copyright © National Academy of Sciences. All rights reserved.

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8 The spiîol golLxg M87 os seen Ðilh 7' rcsolutíon' Fìs|iîe galarg M87 as seen aíth an optícal 7 The l)71n, tio" tttot pott¡ble Øíth er'islìñg rcilìo relescopes spìto¿ Fìeu¡e telescope gioíng 7" tesolution The uhbþool galary as seen 1þith 7' resohiìon' The whi pool ¿alaxg,M51' as seen þith an optí' 9 Figure gioìn! 7" resolulion' cal telescope i I- l Copyright © National Academy of Sciences. All rights reserved.

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seen tDíth 7' xs ting tad,io t el¿sc opes. 12 Thé bared spi¡al gala*g NGC 1300, a's seen Th.e barred' spâ¡al' gala*E NCC 7300' as seen r-igute 11 of existirl! radío Loith 7' lesolution, begond the cøpabi\ta optícal telescope giDing 7" rcsolutìon telescopes, Copyright © National Academy of Sciences. All rights reserved.

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ïï I strongly supported small but active astronomy programs' These few schools then ãevelopeil into the only graduate departments in the Unitetl States that stressed observational astrophysics, and tley a¡e the schools from which most graaluate astronomers have emerged' Not only thes-e schools, but also schooli that wânt to stør, astronomy programs' face almost insurmount- able problems in the present era with its increased pressure for excellence. Except for a hantlful of radio telescopes, there have been very few major adilitions to tÏe equipment of the existing graduate schools for mâny years. Even mo¡e serious is the fact that most of tle newly created grailuate depart' ments have virtually no instrumental legacy from the past. This problem was recognized about ten years ago when the discussions leading tJ setting up tÏe Kitt Peak National Observatory anil the National Radio Astronomy Observatory were begun. If the Kitt Peak Obserwatory did not exist, the situation in optical astronomy would now be almost intoler- able. At present, some of tìe graduate-student pressure is relieved because students from any institution in the courìtry can use the national facilþ at Kitt Peak. But it is estimated that Kitt Peak can satisfy only 25 per cent of the total demand that will develop in the near future. Furthermore, there is a fundamental disadvantage in reþing solely on the national facilities. Faculty members and students must travel from their home institutions to distant places in order to collect material for their re- search problems. They then return to their own graduate departments to analyze t}'te data. It is usuaþ the case in all experimental science that, as insight into a problem develops, difierent data are required or new tech- niqies must be employed at intermediate stages in the research. It is dificult .meet this requirement unless the research facilities are constantþ at to hand at the home institution. The most efficient use of the telescopes at Kitt Peak and NRAO would be in the Ênal push toward solution of problems, after observational techniques had been thoroughly tested on nearby mod- ern instruments. Thus, the necessariþ limitetl period with a larger telescope and good skies for optical observers could be usecl far more productiveþ' it is the opinion of this Panel that a number of graduate schools in tÏe country should be supported in tlreir attempt to acquire moderate-size tele' scopes so tåat such a icheme of operation could be adopted generally' There a Iimit to tlie size of the optical telescope that can be iustiûed i*, åf "orrrse, in parts of the country with low percentages of clear nights' In tlre opinio'l of ihe Parrel, telescopås hrger than 48 inches should not be built in areas of relatively poo, *""|h"r. Ho*"u"t, ít is abundantþ clear from results ob- tainecl, íoiexample, at the Case Institute of Technology, the University of !t Copyright © National Academy of Sciences. All rights reserved.

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t, Wisconsín, and the University of Michigan that telescopes of 24- to 4O-inch size can anil have contributeil enormously to tle progress of observational astronomy. The research of both faculty and students _at these institutions is of high caliber, and exempliffes what can be done under relativeþ poor sþ conditions. The existence of modern telescopes at individual graduate schools has many advantages. À healthy ,"s""r"L atmosphere is almost automatically f"culty and students alike. The equipment is available for "r""i"d stronoirical pioblems that could not be solved on an expeditiola,ry "*orrf many a basis at a nauonal fãciüty. Specíal work on novae' comets, planets, and the moon at certain unprediótable times requires obsewations thât could not be made at a national observatory huntlreds or even thousands of miles away' Any problem requiring close iurveillarce, such as those posed by irregular ]rarialle stars, eJipsirig binaries, int¡insic variables, and tìre radio emission of Jupiter, cannotie ãealt with away from home because the neecl is for ,"j"uiu,l obr"*"tions at selected tímes. Most importânt is the fact that most uniiversity-connccted astronomeïs are engaged in teaching and hence a¡e on students are' t-he campus for three quarters of the year. A'nil this is where the If maxiirum use is to be made of equipment, it must not be locateil hun- dreds of miles away, but must be easiþ accessible, not more than one hour's travel time awaY. MANPOWER We have now outlined the present position of optical and radio astlonomy with respect to the facilitiei needeil for an aggressive attack on problems awaitinj solution. There remains the important question of the balance l¡e- t*e"o tie creation of facilities and tìe number of astronomers that wiII be demanding observing time when the facilíties are completed' The a-nswer to this question cannot be given in hard bookkeeping terms' because the availability of facilities afiects the choice that young scientists l, make on whether to g; into tÌìeoretical or into observational astronomy' The for evidence we have cit-ed earlier in this discussion-the unsatisûed demand centeï and the desire of many univer- the telescope time at maior observing sity graduate departments for modern, locaþ based observing equipment- poLis to tlte current severe limitations in facilities' Fine new instmments ^o.rdonbt"dly do attract and inspire imaginative use by outstanding young 28 ,i tn Þ -,.. Copyright © National Academy of Sciences. All rights reserved.

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lr ì ì LC scientists. Without allowance for such intangibles, the Panel has examined the growth rate in the number of asttonomels in recent years, anil has at- tempteil to set upper and lower limits on tìle nunber of U. S. astronomers a decade hence. The conclusion points to no less than a doubling in t}re next ten years. If the current rapid growth in graduate enrollment continues, the factor of increase may be as large as 2.4. Truiníng of As'tronnmers Comparcd to Ttainíng of Other Phgsical Scíenfists Astronomy is one of the smallest disciplines among the engineering, mathe- matical, and physical sciences. The annual proiluction of Ph.D.'s has been widely used as an index of the growth rate in these Êelils, The following studies contain material relevant to the present discussion: Doctorate Productíon in tJni,teiJ Statas Uniqersitíes. Ofice of ScientiÊc Personnel of the National Àcademy of Sciences-National Research Council, Publication 1142. (See also Phgsics Toil'ag, 15:21, 1962 for ilata on physics Ph.D.'s.) Comparìson of Eørned Degrees Aaarded 7907-1962 ttsith Ptoiectioru to 2000. Nàtional Science For:ndation Report NSF 64-2. lnoestíng án Scíentìfic Progress. National Science Foundation Report NSF 6l-27; also Report NSF 62-43. Meating Manpouer Naeds in Science ønd' Technologg. Report No. 1, Graduate Training in Engineering, Mathematical, and Physical Sciences, by President's Science Àdvisory Committee, Dec.12, \962. The semilogarithmie plot of Figure 17 shows the annual U' S. Ph.D. proiluction in astronomy, physics, and all physical sciences (ûrst two refer- ãnces above ) . It is apparent tha t ouer the long term +Áe country's astuonomy education system has not consistentþ maintained tÏe smoothed growth rate of about 7 per cent per year (doubling time, 10.2 years) that has prevailed in related ,ãi"n""r. The decline in the period 1935-4I may have been causeil by the paucity of ¡obs in astronomy at a time when the field ofiereil many fáwer industrial and government openings than were available to physicists' The Ph.D.-production rate is perhaps a less reliable basis for estimating tÏe U. S. wolking force in astronomy than in othei physical sciences because of the importani fraction of foreign-born, foreign-trained scientists in the group. Môreot er, there is good evidence that an appreciable proportion of ihe present astronomy force transfened into astronomy aftel Ph'D' training in o-ther disciplines, such as physics and engineering. Yet Figure 17 shows 29 Copyright © National Academy of Sciences. All rights reserved.

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tl:l 'i ,l;l il rl i,. .t r970 1960 1950 r940 1930 1920 Fígure 77 sciences ùt the fJnitect States' Annual Ph.D, 11ro¿uctìott itu attÍonony and other Ttlrysical t i &_ I 1,u.. Copyright © National Academy of Sciences. All rights reserved.

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steady growth at about 3.8 per cent a year ( l9-year doubling time) through all the lostwar years, including the I950's, when physics-Ph.D. proiluction was onã plateau. Since 1956, there have been signs of an upsurge that may lead to a much higher growth rate. Before exploring the implications and making a projection based on the best cu¡rent data, it ís of interest to con- sider alnother'index of research activity in astronomy to see if corroborative evidence exists. rdÀIt 89í PER Fígøe 78 the lntemational Astrononúcal Uniotu 7921-1963' Crouth of U,5. membetship ¡tu proiecte¿ to f972. tlw Infernatianal Astronomical Union (J. S. Membershâp ín Figure 18 shows the number of U. S' members in the International Astro- nomical Union (IAU) from 1923 to 1961. Membership in the IAU is univer- sal enough among established professional astronomers so that weighting in favor of [he intemational-minded is negligible. Yet the standards of member- ship are such that, at any one time, a number of young and productive ,"rã"."h"r* who make heavy demanils on facilities are not being counted' The membership ffgure is tìerefore lower than the actual force, presumably by a constant percentage in a period of stable growth. The enumeration is insensitive to fôreign birth and training, anil to transfer into asEonomy from initial training in another ûeld' The plot in Figure 18 shows a steady growth rate of-4'5 per cent per year ( iloubling Umã, fO years) from 1923 to 1955. The-tlree points {rom (The íSSS ìo fSO¿ Jrow a sharp ltptorn to a doubling time of nine years 1964 point is an estimate from the U. S. National Committee of the IAU, 31 lì -t þ B'- Copyright © National Academy of Sciences. All rights reserved.

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tle impression gainedJrom the glowÌb based on nominations. ) This conffrms tìe American Astronomical Society, and from the rapid in membership of swelling of the astronomy graduate student population' Since the latter gives the most up-to-tlate irformation, it has been made tl-re subiect of a special study. . Graduate Stuiønt Populntion in Astrotwmg Depattments The current survey gïew out of a census made by W. E. Howard III for the 1962 Conference on Graduate Education in Astronomy, held at Bìoomington, Indiana. Material for this study was gathered by inquiries to the 28 clepart- ments listed in the brochure entitled "Careers in Astronomy," published in 1962 by the Committee on Education in Astronomy of the American AStro- nomicál Society, plus four new departments known to the committee' The replies on tìe .t,rmbets of students in the falls of 1957, 1960, and 1963, plus eaich deparunent's estimate of the 1966 enrollment, are listeil in Table 1' The totals, plotted in Figure 19, establish a growth rate within the graduate schools of 19 per cent a year (a doubling time of 4.0 years )' This is near-þ twice the rate attained or projectecl in related sciences A simple extrapola- tion predicts 2,590 graduate students in astronomy ín 1973 The ffrst efiect of this surge was a Þh.D. output of 30 in 1962, considerably higher than ìn any previJus year, but a figure consistent with the assumption that the ph.O.t should'be at least 10 per cent of the student population, with a three- year lag to allow for the fact that rapid growth means a hígher proportion of ginning graduate students. be - What it the source of this boom and how long will it continue? In the opinion of the Panel, some o{ it was a natural growth, stimulated by general among science-inclined undergraduates of the exciting derrelop- "i"."rr"r,astronomy of the postwar years, and fostereil by wise supplemen- ments in tary support of resåarch and instïumentation in many universities by federal A new anil strong influence came with the ffrst Sputnik in 1957 ancl "gá.t"iår. tÈe widespread interest in space that followed. Since a good part of the university-based space efiort is in special institutes separate from astronomy departments-often dominated by physicists, geophysicists, and engineers- thJ rapidly growing student population in the departmental tâbülation of Table ì reprãsents a broad spectrum o{ interests, and something like the tra- ditional pioportion of tlre students may be expecteil to go ínto ground-based observational astronomy. The new astronomy students irndoubtedly lepresent a shift in interest Copyright © National Academy of Sciences. All rights reserved.

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7 THE NUMBER OF CA.NU ATE STUDENTS IN ASTRONOMI TABLE BY INSTITUTION 1966 1960 1957 1963 . (nxrncrao) 22835 Untuersitu ol Arízona O 19 22 CaliÍorûia. In'stítute of Tealnolagg 35 16 35 23 tlnÍaeîsítv of CøInÍoîrìa, BØkelea 65 20 28 20 Unìoeßitg oÍ Ca.UÍomùt, Los Angelzs 40 3 51720 Case htstitute of Techrølogv 1 71420 Uítueîsftv of Chí'cago 6 641 Unioeß¿tg of Chûìnnati 0 42 I5 Uflioeßìtg oÍ Colþru¿o 50 7 5412 Columbíø UûbeßìtlJ 5 Uníoeßítg 2 Conell 01220 Florìdø Unbetsìtg of 0 40 31 Georgetoün Un oeßtfg 45 22 40 28 Haroard Uníoeßìta 55 24 813 Utuloeßìtu oî lllítuois 17 2 25 23 30 Indí.anafJnìaersítE 16 0610 Iotþ4. State Uníaeßitg oÍ 0 026 Un¿aeßitg O Louí9íøna Sta.te 22555 Ilntuersüg of Marllønd 0 32 28 Untuersttl! of Mtch¡'gan 76 40 011 NorthØestern uníoeßìtg 15 1 71425 Ohio St tte Unheîsìtu 5 81520 unìoeÍsifv ol Pennsgh)ania 3 6710 Pr¿ncehn Aníþeßíig 6 r8-13 RensselnetPolgtechn¿clnstitlûe 0 228 tJniÐeÌsitg oî Roch¿ster I É712 Stanford Unloeß¡tg 5 51225 ' Unioersitg of Terns 0 026 Vand.erbilt Uû¡þeßítg 0 o2L6 l Uniþersítg oÍ V¿rginial 2610 Wesl.egafl Uníoersitg 0 19 14 Uníoersitv of Wbconsín 30 2 62840 Yalþ Uníoeßíta 5 Totals within the 25 per cent fraction of the physical-science doctorates thai have been going into astronomy, physics, and geo-scien ces (Doctorate Production ín Uãitel ffiates Uníoersitíes, see p. 30). This percentage has remained stable over many years, as has the over-all fractíon of abdut one sixth of total doctorate production going into all the physical sciences' The shift diil not need to b; a hrge one to produce the drastic increase in astronomy alone, since astronomy plt.¡.t irr the years 1957-62 were only 3 per cent o{ t'hose in physics, rising to just over 4 per cent in 1962. An íncrease of the astronomy Ph.D.'s to 8 pei cent of the physics production, as was the case in the pre- nuclear decaãe of the 1920t, or even to 10 or 12 per cent, woulil not be Copyright © National Academy of Sciences. All rights reserved.

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UNIFORÀ{ CROWTI¡ / , :¡ÀPERED GROWTII NUIIIER OF ASTRONOI4ENS GB¡.DUATE STI'DE\TTS I]NIFOR}I CNOWTII , 19ø PER YE,lû TÀPERED GÂOWTII 7 ¡¡n va¿¡ n¡ 1973 Fígurc 19 Ninnbet of gra.Iuate st¿(lents í'n asftonontg, the number of PhD"s 1954-1962, and Prcìecte¿ Ph.D. prcductíon an¿ total nuñl)et of \stronomeß to 7973' I l I I I L-"- Copyright © National Academy of Sciences. All rights reserved.

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emphasis among the physical -sci- tantamount to a drastic redístribution of when o{ astronomers is stilitlisproportionately small ,¡" ;ö;ä ;the"*¡er manpower in physics' geophysics' and " total "î"ärï"" astronomv combined. """^îîãrå"r be support for increas- a" tustain a high growth rate there must National Defense Education Act is t-.,;;;; of øraduate ,úraÉots' The in a1l the phvsical sciences' and the efiect Ïiäil"ff;.'"i;"ì"pìr"'i""itt maximumpáint' The new National Aero- ;ililåå;;"i vet '"""h"d supportetl Administratiãn iN¡'s¿') i"16ç5hip- ^program and 886 fel- iäöä.ii;;r;ãJ. i" il n"1'{' ii" r0 institutions tur1s62-63' sources' to "",îu"r- ""Jóp"""' to nsease' according to- NASÀ it is expected lows in 1963-64; rn view of the announced pur- ;îi;;;*'t; as 4,00ô graduate students' fraction of the recþients could be assumed' :::ili1Ë;s;;;;*i" *ho *ot'Id otherwise have go, e into some other ;;;il;r*¿""" í""il this influence could accel- ;hy"*üì;;;;. ,{ltho'tghnitis conceivable that high ffgure' it is probably p'"'"nt very erate the growth late even "yoJ th" Ñns¡' fellowships mav be not safe to attempt such " p;;ñ;ti"";*' rhe cur- o"" ofthå sources of support that will sustain the ;;;ã,;";"d ", of inte¡est in astronomv in the universities' ;';;;";;;;n""sion A Ten-Iear Proiectíon in the Uniteil States will be Two projections of the number of astronomers growth rate in It may be assumed that the 19 per cent a;ear long enough to "aì"nñ,"d. truduáte-st.'ilent pàpuìation- has-bee¡ in efiect äsiffi;; long as the growth rate is sustainetl' achieve a new equilibtitt"', "íã'tttui, "s at u 19 p"t cent a year rate' starting Aä ph.li. ptàa"Ë,íon will also increase f he production' it mav il;;ouap* of 30 in 1962' For a high estimate on tP-h.D. procluction.will rate i further be assumed th"t th;';;r""t g:rowth 1SOS-1SZS Since it is difficult to iä*"i" ""¿""ged in the tetþ' p"t"iod can be sustaineil over a long maintain that such u pft""o-áouily high rate on some assumption as ;;i;ã, ; t""t" conser-vatíve ostimate rÀust be baseclFor the low estimate' a e i" ift"'ait"i"g of a tapering fi of the growth rate' t"i tfte ûrst year' decreasing uniformly 19 per cent $owth rate ¡ """"ft tU" Z per cent lóng-term growth rate char- tt"t*ã by 1.2 per cent per year to t ten-year period' **õiah; i aì" nf..i"¡ *ià""át i" genåral by the enil oI theSociety on Janu- "ä".tråã " r,36^0 itmbets ãf the Ãmerican'Astronomical hold doctorates or professorships' "-, I laR4 620 have U. S' "iådt"1t"t santl fringe asrronomers and persons "a"a"s ome ü,J'",,mI)-J;"d""u*a( 35 i I á-... Copyright © National Academy of Sciences. All rights reserved.

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IN THE PREDICTED ASTRONOMICAL MANPOWER TABLE 2 UNITED STATES uNrFoRM cRowrr¡ RÀTE (79% a gea¡ or 4-gear d,oubling perlod) 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 43 59 71 83 98 118 I38 162 50 I95 Neø Ph.D.'s 663 703 751 8-tr 882 967 7071 7193 1337 1512 SubJotal . 11 14 16 18 20 10 11 12 13 l-54 23 Loss 653 692 740 799 869 953 1055 1175 1317 1489 Total 620 ø geaî ín first geaL d,eøeasíng to 7% ø geøÌ at eñd) cRowûr R.41æ (791¿ TÀPERED 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 42 49 56 72 8_t 90 98 106 113 64 Neu: Ph.D,'s 662 701 747 800 860 928 7004 1087 717',/ 7272 Sub-totøI 10 10 77 13 14 15 16 18 19 t2 1,5% Loss 652 691 736 788 847 914 989 1071 1159 1253 t: Total 620 ,il with primary interests in other ûelds, but there is probably approximate compensatíon by the active astronomers in the other 54 per cent of the mem- ,,1 bership who do not hold doctorates or professorships. The National Register ,i 'j. of Scientific and Technical Pe¡sonnel lists 483 full-time astronomers in the ii United States in 1962. (W. L. Koltun of the National Science Foundation, ,tl,ì il :t,l which maintains tle Register, estimates that tÏe listing, basecl on responses ii to a questionnairg is only 80 per cent complete. If allowance is made for ) l incompleteness and for about 40 Ph.D.'s added since 1962, and also for the standard loss of 1.5 per cent a year by death or retirement, found by the l ll National Science Foundation to apply generaþ ín scientiffc-manpower srü- veys, the corrected total becomes 626 full-time astronomers at the beginning :, of 1964. This is a confirrnation of the previous ffgure of 620, and that number i may be adopted as a base for the prolection. l Two projections are worked out in Table 2 and plotted in Figure 19. l|1 The high estimate shows an increase in total ashonomical manpower by a l l' ; / lactor o12.4in ten years. The low estimate proiects an increase by a factor of 2.0. Thís tabulation does not attempt to classify astronomers by categoties ì,,' of inte¡est-theoretical or observational, optical or radio, ground-based or ili space-oriented. Since shifts in emphasis occur quite slowly, no complete :' lrl overturn ín percentages would be expecteil in a decade. A prediction would I l ,i be hazardous, but the proportion of tlle student population in graduate de- i tLl partments that place emphasis on ground-based astronomy, compared with I .; ')' 36 l: Copyright © National Academy of Sciences. All rights reserved.

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ì the proportion in departments that have taken up space-orienteil astronomy, *orild årgo" againsf any immediate drift away from the present division of interest. Conclusían The surge of students into the graduate departments of astronomy has fol- no sign lowed aiteaily upward course for at least six years, and as yet shows from the cur-rent enrollment are àf ,ou.rding oif. If only the Ph.D.'s expecteil in the countetl, a"sharp increase in growth rate of the number of ast¡onomers in the count yis ioevitable. Arry reasonable assumptíon about a ¡ounding-ofi *o*tí t"t* of graduate enrollment leads to not less than a iloubling of the iumber of astrolnomers in the United States in the next ilecade' --' iin"" grounil-baseil astronomy has been shown Jo be uncler-instru- program of new facilities that menæd forïe demand already ""ittittg, " to work efiectively at moilern *ilt p"t-it roughly twice ", -åoy obseivets i"lããop", *orrãt úe consiclered rash. There will sureþ be more than enough astronomers waiting to use the new instruments' Copyright © National Academy of Sciences. All rights reserved.