Department Of Terrestrial Magnetism Research Articles

Edward R. D. Scott (1947–2021): A tribute to an exceptional scientist and wonderful man

Edward R. D. Scott (1947–2021): A tribute to an exceptional scientist and wonderful man

Vera Cooper Rubin

Vera Cooper Rubin

An Early Big Hit to Mars May Have Scarred the Planet for Life

PLANETARY GEOLOGY Earth has its high-standing continents and low-lying ocean basins, thanks to plate tectonics. And Mars has its smooth northern lowlands and its cratered highlands. But there's no credible sign that plate tectonics ever operated on Mars, so how did a third of the planet come to be as much as 4 kilometers lower than the rest? For the past quarter-century, a leading theory has held that a giant impact battered the young planet and excavated the northern lowlands, but that idea seemed to have serious problems. Now, two new studies purport to ease the difficulties with a giant impact. In one study, researchers reveal the true dimensions of the huge “Borealis basin,” making it look much more like the crater of a giant impact. And a second group has run simulations that suggest how an impactor could have blasted out an 8000-kilometer-wide crater without melting it into an unrecognizable puddle of magma. “I think there's much to recommend [a giant impact] now with all this new work,” says Sean Solomon, a planetary geophysicist at the Carnegie Institution of Washington's Department of Terrestrial Magnetism in Washington, D.C. ![Figure][1] Striptease. Removing the Tharsis volcanoes of Mars (reds and yellows, left panel) from part of the northern lowlands (light blue, right panel, top ) uncovered an elliptical basin that looks like an impact crater. CREDIT: MARS ORBITER LASER ALTIMETER (MOLA) TEAM/GODDARD SPACE FLIGHT CENTER/NASA Last month, planetary geophysicist Jeffrey Andrews-Hanna of the Massachusetts Institute of Technology in Cambridge and colleagues presented their test of the giant-impact hypothesis at the Lunar and Planetary Science Conference (LPSC) in Houston, Texas. In 1984, planetary scientists Donald Wilhelms, now retired from the U.S. Geological Survey, and Steven Squyres of Cornell University first proposed that a huge impactor had blasted out the Borealis basin. Fitting a circle to the “dichotomy boundary” between the basin and the highlands, they suggested that the circle could mark the outer edge of a huge crater. But the fit was too rough to win many converts. So Andrews-Hanna and his colleagues looked for a better way to trace out the dichotomy boundary. The great Tharsis volcanic complex had obscured much of the boundary when it smothered one-quarter of the planet with lava hundreds of millions of years after the lowlands formed. To “remove” Tharsis, they drew on measurements of martian gravity and surface height from the past decade of Mars orbiters. Subtle variations in the pull of gravity—evidenced in variations of a spacecraft's orbit—reflect the added mass of Tharsis lavas as well as the extent of the deep, less-dense crustal rock buoying up the highlands. The height of the surface constrains the volume of added lavas. By combining the data in a model, the researchers erased Tharsis's contribution to the present surface and traced the topographic edge of the Borealis basin right under Tharsis. Rather than a circle, the best shape for the basin turns out to be a 10,650-kilometer-long ellipse, they reported at the LPSC meeting. That's a familiar look for big impact basins. The 2300-kilometer Hellas impact basin in the southern highlands, for example, is also elliptical and also underlain by a uniformly thin crust. And there's no particular reason, Andrews-Hanna said, why the giant-impact theory's only serious rival—a peculiar sort of churning deep within the planet—would produce an elliptical basin or the observed sharp boundary between thin and thick crust. The other long-standing objection to impact excavation was the mere survival of a craterlike feature of any sort. Any object hundreds of kilometers across that hit Mars at tens of thousands of kilometers per hour, the thinking went, would heat the planet so dramatically that any crater would disappear in a sea of globe-girdling melted rock. Now that computer models are up to the task of simulating giant impacts in detail, that thinking is changing. As most recently reported at last December's American Geophysical Union meeting, planetary scientist Margarita Marinova of the California Institute of Technology in Pasadena and colleagues have simulated a range of giant impacts on Mars, all producing 8000-kilometer craters. They found that the melt from vertical impacts does in fact obliterate the crater but that faster, low-angle impacts do not. Simulated glancing blows at angles below 30° produce less melt overall and splash much of it into space. The giant-impact mechanism “was always thought dynamically impossible,” said Andrews-Hanna at LPSC. “Now you can't dismiss the possibility.” The two studies are convincing researchers that “the giant impact lives (after all)!” as planetary geophysicist Roger Phillips of Southwest Research Institute in Boulder, Colorado, playfully writes in an e-mail. Few are entirely won over yet, but a giant impact worked out as the origin of Earth's moon. Perhaps it will also serve to explain the deepest mystery of martian geology. [1]: pending:yes

The Re-Os isotopic system: geochemistry and methodology at the Geochronological Research Center (CPGeo) of the University of São Paulo, Brazil

The Re-Os isotopic system is an important tool for the study of mantle-crust processes, geochronology and the tracing of source reservoirs for metal deposition. Rhenium and osmium differ fundamentally from other lithophile isotopic systems with regards to their behavior during partial melting processes, coupled with the chalcophile/siderophile nature of both elements. These differences make the system extremely useful for a number of novel applications not traditionally addressed by lithophile isotopic systems. A low-blank technique for the analysis of Re-Os isotopes in geological materials has been established at the Geochronological Research Center (CPGeo) of the Geosciences Institute of the University of São Paulo, Brazil, with the aim of furthering knowledge of regional geology, tectonic evolution, petrology and ore deposition in South America. The techniques described here use isotope dilution to simultaneously determine the concentration of Os and Re as well the Os isotopic composition of geologic materials. Sample digestion and sample-isotopic spike equilibration are achieved in sealed borosilicate glass tubes at high temperature. Osmium is separated and purified by carbon tetrachloride solvent extraction and micro-distillation techniques. Rhenium is separated and purified by anion exchange chromatography. Accuracy of the concentration and isotopic determinations is monitored by the analysis of a certified reference material (WPR-1) and the use of the Department of Terrestrial Magnetism (DTM) Os isotopic standard. Measured values and precision of these standards is within error and comparable to established Re-Os laboratories.

James Alfred Van Allen

James Alfred Van Allen

George W. Wetherill (1925–2006)

George West Wetherill, a pioneer of geochronolgy and planetary science, passed away from heart failure at his home in Washington, D.C., on 19 July 2006, one month short of his 81st birthday Wetherill, director emeritus of the Carnegie Institution of Washington's Department of Terrestrial Magnetism, made major contributions to a wide variety of fields, including geochronology and the formation of the planets.Wetherill was born in Philadelphia, Pa., on 12 August 1925. After service in the U.S. Navy in World War II, where he taught radar at the Naval Research Laboratory, he entered the University of Chicago on the G.I. Bill. Wetherill obtained four degrees, culminating in his Ph.D. in physics in 1953. He began work at Carnegie's Department of Terrestrial Magnetism in 1953 and became part of its geochronology group, working with Thomas Aldrich, George Tilton, and Gordon Davis.

George West Wetherill

George West Wetherill

A tribute to the life and work of George W. Wetherill: Some reflections of his career at DTM

George Wetherill and I worked together as scientific collaborators when I was a postdoctoral fellow in 1977-1978 at the Department of Terrestrial Magnetism (DTM) of the Carnegie Institution of Washington (CIW) in Washington, D.C. We worked on problems of meteoroids interacting in Earth's atmosphere along with Richard McCrosky at Harvard College Observatory and Zdeněk Ceplecha at the Ondřejov Observatory in Czechoslovakia and also with Sundar Rajan who had already arrived at DTM from the University of California at Berkeley before me.

Roy Middleton

Roy Middleton, emeritus professor of physics at the University of Pennsylvania, died at home in Media, Pennsylvania, on 23 June 2004 after a prolonged illness.Middleton was born on 3 October 1927 in Atherton, a suburb of Manchester, England. He took his first steps toward a scientific career at the nearby Wigan Technical College, a direction that in the English system of the time would have taken him into industry. The University of London recognized his ability, which gained him enrollment there. He received his BSc in physics in 1948 and earned a PhD in physics from Liverpool University three years later under the supervision of Leslie L. Green, who later became director of the Nuclear Structure Facility at Daresbury, UK.The 8-MeV deuteron cyclotron at Liverpool was used for some of the earliest studies of direct nuclear reactions, and Middleton, first as a graduate student and then as a research associate, enthusiastically measured (d,p) angular distributions using photographic plates. That work led to his studying (d,n) reactions for his PhD thesis using recoil protons in nuclear emulsions as the detection method. He remained at Liverpool as a research associate until 1955.That same year, Middleton accepted a position as scientific officer at the Atomic Weapons Research Establishment at Aldermaston, soon after it had acquired one of the first tandem Van de Graaff accelerators, an instrument ideal for exciting direct reactions. He was a supremely creative experimentalist, both in the planning and execution of experiments and in the development and use of accelerator peripheral equipment. Of particular significance was his use of a multiple-gap charged-particle spectrometer for observing the products of nuclear reactions. The instrument allowed rapid accumulation of large amounts of data that unraveled the structures of scores of nuclei. The University of Pennsylvania took notice of that work and Middleton’s skills with the then new tandem accelerator, and invited him to direct the new Tandem Accelerator Laboratory. He joined the faculty there in 1965 as a professor of physics. Tandem accelerators achieved a new versatility and ease of operation through Middleton’s development of a negative-ion source capable of producing useful currents from a large fraction of the periodic table. His related resource document, which he called the “Negative-Ion Cookbook,” circulated as the bible of the nuclear physics and, later, accelerator mass spectrometry communities. He was later (1979) awarded the American Physical Society’s Tom W. Bonner Prize for his work on the development and use of ion sources. Middleton entered the field of accelerator mass spectrometry very early and collaborated with Jeffrey Klein of Penn and with Fouad Tera, Selwyn Sacks, and Julie Morris at the Carnegie Institution of Washington’s Department of Terrestrial Magnetism. Using beryllium-10, they demonstrated that lava from island-arc volcanoes had components that had once been on the ocean floor and had been subducted to the roots of volcanoes in transport processes lasting millions of years. Their results were reported in Geochimica et Cosmochimica Acta in 1986. Middleton developed or refined the accelerator method for the other cosmogenically generated isotopes carbon-14, aluminum-26, chlorine-36, and calcium-41. He actively participated in the science resulting from the use of those isotopes in a range of studies involving lunar samples, meteorites, tectites, and the erosion of rock surfaces and soils. In collaboration with the Hospital of the University of Pennsylvania, Middleton produced the short-lived positron-emitting isotopes carbon-11, oxygen-15, and fluorine-18 for diagnostic studies of patients. The tracers were immediately transmitted to the hospital in gaseous form through tubing. That approach proved so successful that the hospital acquired a cyclotron to open the door to continued medical opportunities.From 1986 to 1991, Middleton held the Andrew W. Mellon Foundation Professorship in physics at Penn. In his final years at university, he did outstanding work on negative ions, particularly on dianions, work often referred to in the literature of theoretical chemistry. He retired from Penn in 1996.For thousands of undergraduate students, Middleton was an exceptionally effective, patient, and supportive teacher. If a student from his class in introductory physics needed his help, Middleton would, without complaint, interrupt his work at the tandem accelerator to provide that assistance. Although he taught the same course many times, he captured his students’ full attention with new notes and ideas. He brought to the classroom the same freshness and enthusiasm with which he approached his research. In 1969, the Lindback Foundation awarded him the Christian R. and Mary F. Lindback Award for Distinguished Teaching. [Editor’s Note: Louis Brown, one of the authors of this obituary, did not live to see it published; he died on 25 September 2004. See his obituary on page 81 of this issue.] Roy Middleton PPT|High resolution© 2005 American Institute of Physics.

A Conversation with William A. Fowler ? Part I

Nobel laureate William A. Fowler recalls his early education in physics; his part in the history of nuclear physics at the California Institute of Technology in the 1930s; parallel efforts elsewhere, particularly at Berkeley and the Department of Terrestrial Magnetism in Washington,D.C.; his contacts with J. Robert Oppenheimer; and his work with Charles C. Lauritsen and Tommy Lauritsen before and after World War II.

A proton accelerator in Trondheim in the 1930s

ABSTRACT: Johan Holtsmark at the Norwegian Institute of Technology (N.T.H.) in Trondheim, Norway, built a Van de Graaff generator for nuclear disintegration between 1933 and 1937. This is believed to be the second Van de Graaff generator in Europe and the first particle accelerator in Scandinavia. Holtsmark's successful project followed the failed attempt at N.T.H. by Olaf Devik in the 1920s to develop a discharge tube for nuclear disintegration driven by an evacuated Tesla coil. The genesis of Holtsmark's project was the interaction with Odd Dahl, who had constructed a Van de Graaff accelerator at the Department of Terrestrial Magnetism, Carnegie Institution of Washington. Holtsmark approached organizations potentially interested in cancer research and treatment for financial support. The electrical engineers appointed to build several parts of the accelerator had been radio amateurs, like many accelerator pioneers at the time. The team had to construct almost everything themselves given financial constraints and the lack of a supporting electrical industry. When operative in 1937, the Van de Graaff generator was already a comparatively small machine. The Trondheim scientists chose to develop it as a precision machine for proton capturing experiments in light elements. The accelerator proved a useful tool for research and teaching until 1963, when it was shut down and given to the Norwegian Museum of Science and Technology. This article seeks to answer why Holtsmark engaged in such an ambitious project in the periphery of Europe's scientific community and how he succeeded at a small department with several coexisting research activities.

Radio Observatory at Maipú Completes Mission, Closes Doors

After 40 years of operation, the Radio Observatory of the University of Chile (ROM), located at Maipú, has closed down. The ROM came to life in 1959, 27 years after Karl Jansky’s momentous discovery of cosmic radio waves. The facility was the result of two cooperative programs of the University of Chile, one with the department of terrestrial magnetism (DTM) of the Carnegie Institution of Washington and the other with the University of Florida in Gainesville. These efforts were initiated and encouraged by the late Federico Rutllant, director of the National Astronomical Observatory of the University of Chile, who wanted to have the university involved in radio astronomy. Rutllant’s more ambitious interests led to the installation of large international observatories in northern Chile. At the DTM he met Merle A. Tuve, who was enthusiastic about developing radio astronomy in South America. In Gainesville, Rutllant met Alex G. Smith, who wanted to observe Jupiter’s decametric emission from the Southern Hemisphere.As a student I tested the prospective sites. After Maipú was selected, I worked with the DTM in designing and building a 1200-meter-long, 16-element interferometer to observe the Sun at 175 MHz. John W. Firor and Bernard F. Burke, then at the DTM, helped me with the fundamentals of interferometry. Jorge May, also a student, worked with Thomas D. Carr on different types of antennas to observe Jupiter. The first successful observation was made on 25 November 1959, when the interferometer recorded a strong solar storm. As far as we know, the ROM was the first operating radio observatory in Latin America. It worked at very low frequencies and carried out observations of the Sun, pulsars, SN1987A, the Magellanic Clouds, and so forth. However, its most successful tasks were the decametric observations of Jupiter that spanned two Jovian years, and the 45-MHz continuum survey of the southern sky. The latter survey was done with a large filled array that worked as a transit instrument; because of problems inherent in very low-frequency observations, the southern survey took 15 years to complete. The observations were combined later with others made from the Northern Hemisphere with a similar antenna, resulting in an all-sky survey at 45 MHz.The ROM made significant contributions to teaching. A number of electrical engineering students obtained their degrees under the guidance of engineer Juan Aparici, who was responsible for most of the electronic design and construction. Also, several students received MS degrees in astronomy.The ROM became a solid research center, establishing cooperative programs with international institutions. The first was in the mid-1980s with Columbia University in the US, through the installation and use of a 1.2-meter dish, built to observe molecular line emission in the mm-wavelength range, at Cerro Tololo InterAmerican Observatory. Carbon monoxide is important in the interstellar medium because it radiates a strong line in the 1–0 transition and is a good tracer of molecular hydrogen, which does not emit radio waves. The main goal, successfully accomplished, was to make a survey of the southern Milky Way in that transition. This pioneer project opened the rich field of mm-wave spectroscopy. Part of the ROM’s legacy is a new generation of Chilean radioastronomers who are involved in important cooperative programs with the US, Japan, and several European countries.The ROM had scant funding, but it received equipment donations from the University of Florida, the NASA satellite tracking station near Santiago, and the European Southern Observatory. Many people associated with the ROM deserve mention here, but space limitations prevent it. Credit for keeping the ROM running belongs to Jorge May.So, with the great satisfaction of knowing that the ROM achieved its primary goal, yet with deep sadness, we have turned the power off at the Maipú Radio Observatory. The radio astronomy observatory at Maipú, Chile, in October 1959. In the left foreground is a Yagi radio antenna of the solar interferometer; on the right is the inclined plane of another antenna. In the middle, near the building, the tall V-shaped structures make up the corner reflector. Both the inclined-plane antenna and the corner reflector were used primarily for observations of Jupiter.PPT|High resolution© 2001 American Institute of Physics.

Honors

AGU Past‐President Frank Press, who is stepping down on June 30 as president of the National Academy of Science, has been appointed the Cecil and Ida Green Senior Fellow at the Carnegie Institution of Washington. Press will join Carnegie in September and will serve in residence at the institution's Geophysical Laboratory and Department of Terrestrial Magnetism in Washington, D.C.

Annual report of the Director, Department of Terrestrial Magnetism, 1972–1973 : CARNEGIE INST. CARNEGIE INSTITUTION, WASHINGTON DC, DEC. 19873. 318P

Annual report of the Director, Department of Terrestrial Magnetism, 1972–1973 : CARNEGIE INST. CARNEGIE INSTITUTION, WASHINGTON DC, DEC. 19873. 318P

Sixth Presentation of the John Adam Fleming Award, April 19, 1967

The honor paid to Ernest Harry Vestine by be award of the John Adam Fleming Medal would have greatly pleased Dr. Fleming, as it has Dr. Vestine's many friends and colleagues. Dr. Vestine is the fourth recipient of this award who was on Dr. Fleming's staff at the Department of Terrestrial Magnetism of the Carnegie Institution of Washington. This indicates Dr. Fleming's skill in choosing promising young scientists for appointment to that Department. Though Minneapolis born, Dr. Vestine spent part of his youth in Canada and studied there as an undergraduate and graduate. From there came his first contributions to geomagnetism and aeronomy as leader of the Canadian expedition to Meanook during the Second International Polar Year, 1932–1933. There he set up and operated a new magnetic observatory, which has since provided important magnetic data from the auroral cap of the Earth, above 60° dipole latitude. While at Meanook he observed noctilucent clouds and made one of the earliest reliable reports of them from this continent. In 1934 he wrote an important review article on this remarkable and beautiful phenomenon.

Helen B. Warner Prize

Bernard F. Burke of the Carnegie Institution in Washington, D.C. has been named to receive the 1963 Helen B. Warner Prize of the American Astronomical Society. The award honors Dr. Burke's contributions to radio astronomy, especially the discovery of radio emission from the planet Jupiter, and will be presented to him at the Society's December meeting in Washington. Dr. Burke received a doctorate in physics from the Massachusetts Institute of Technology in 1953 and in the same year joined the staff of the Carnegie Institution. In 1961 he was appointed to his present post of chairman of the Radio Astronomy Section in the Carnegie Institution's Department of Terrestrial Magnetism. During 1958–61, he served on the National Radio Astronomy Observatory Advisory Committee, and for the last three years has been a member of the National Science Foundation Astronomy Panel. Dr. Burke is a member of the American Physical Society, the AAS, and the Royal Astronomical Society.

Redetermination of coil constant of sine galvanometer No. 1

Sine galvanometer No. 1 (SGl) was constructed by the Department of Terrestrial Magnetism, Carnegie Institution of Washington, as a primary standard for the determination of the horizontal component of the earth's magnetic field (H). The precision coil for the SGl consists of 40 turns of copper wire wound on a marble form in such a way that 20 turn-pairs can be identified which have the Helmholtz configuration with approximately 300-mm diameters and 150-mm axial spacings. The coil was first measured by Barnett [1921]. Since that time it has gained some importance as an international standard in the determination of H. Because of the importance of the SGl as an international standard, the coil constant was recently redetermined. The new results are compared with the old in Table 1.

Evaluation of average crustal characteristics from reverberation of seismic waves

The seismic records obtained near the shot points during the study of the earth’s crust by the Department of Terrestrial Magnetism, Carnegie Institution of Washington, have been analyzed to investigate the possible origin of the reverberation of seismic waves. The hypothesis of layers of uniform velocities fails to explain the reverberation curves in different regions. As a first approximation, the average gradient of velocity with the depth can be determined and it agrees with the travel-time data provided one assumes the major contribution to be from the conversion of P waves into S waves at the surface irregularities. The average gradient in Virginia, U.S.A., is seen to be 0·075 km s -1 km -1 . When the travel-time curves are investigated on the basis of such a large velocity gradient, the penetration corresponding to rays causing intense arrivals usually associated with the critical reflexions from the Mohorovicic discontinuity comes out to be only 14 km in Virginia, U.S.A. The intense arrivals have to be ascribed now to the focusing effect of peculiar variation in the velocity at about this depth. For example, if sediments extend to a thickness just short of 14 km , the velocity might increase at the base of the sediments to a value greater than the velocity in the upper layers of the converted crustal rock during the formation of the continents. This will give rise to both a low velocity layer and focusing when the velocity again increases at depths somewhat greater than 14 km . On the basis of the ray theory and assuming uniform increase of velocity with the depth, expressions have been derived for the reverberation curves for various kinds of single scattering and the average gradient has been determined for various regions. A mathematical theory for the variation of gradient from a high value at the surface to a negligible value when velocities greater than 8·8 km/s or so are reached would be a logical next step.

Union, section, and committee activities

This Symposium was arranged by W. O, Roberts and held in the Great Hall of the National Academy of Sciences on the afternoon of May 4, 1959. The session opened at 14h 00m and adjourned at 17h 00m.The Symposium consisted of two organized discussions on highly speculative subjects, which stimulated informal debate. The first, on “Solar and Other Cosmic Influences on Planetary Weather and Ionospheres,” was introduced by Seymour Hess (Florida State University), and included discussions principally of Mars, Venus, and Jupiter atmospheric phenomena. Invited comments were presented by Albert G. Wilson (Rand Corporation), Roger Gallet (National Bureau of Standards), William M. Sinton (Lowell Observatory), and B. F. Burke (Carnegie Institute Washington, Department of Terrestrial Magnetism). The first discussion was attended by approximately 180.

On the velocity field of the nearby interstellar hydrogen.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the velocity field of the nearby interstellar hydrogen. Helfer, H. L. Abstract This is a progress report upon the analysis of the 21-cm survey for (b >200, undertaken at the Department of Terrestrial Magnetism, Carnegie Institute of Washington, and reported upon previously (Erickson, HeIfer and Tatel 1959). Rough agreement between Shain's local magnetic pole of the Galaxy (Shain 1957) and the crudely defined pole of the high-latitude interstellar hydrogen suggests that the distribution of the interstellar gas is quite dependent upon the local magnetic field and that the possibility that the velocity-distance relation for the gas is different from that of the stars cannot be ignored. As reported previously, the high latitude 21-cm line profiles give evidence of significant large-scale structure. Accordingly, a solution for the velocity-distance relation of the nearby gas was attempted. Including only first order terms one may write for the radial velocity: V(1, b) = a + sR, where R is the distance and s = K + cos2 b (C + B1 sin 21 + B2 cos 21) + (A3 sin 1 + A2 cos 1) sin 2b, a = W1 cos 1 cos b + W2 sin 1 cos b + W3 sin b. Using subjective estimates of the peak or center of line-profile velocities, solutions for the relative ratios, K: C: B1: B2: A1 : A2, were determined from the seven available values of (1, b) for which V(1, b) + V(1 + 1800, -b) = 0. The preliminary values are: 1.000, -0.820, -0.311,0.182, +0.743, -0.322, in the order given above. The figures quoted are probably already influenced slightly by the occurrence of second order terms, their influence being evident in the observations taken at b = ~ 200. The values of W1, W2, W3, determined from the value of V(1, b) - V(1 + 1800, -b) at the aforementioned zero points, are found to be 1.24 km/sec, 2.62 km/sec, - I .6o km/sec, respectively, but these values are quite crude. If accepted literally, this would suggest that the circular velocity of the local gas is about 3 km/sec faster than that of the stars. The coordinate system used is that defined by the Lund Tables (Ohlsson, Reiz and Torgard 1956) with galactic center at 1 3270, b - 10 and the velocity scale origin is the local stellar standard of rest, as given by the Lund Tables (MacRae and Westerhout 1956). This work was supported in part by the U.S. Air Force under Contract No. AF49(638)-52. REFERENCES Erickson, W. C., Heifer, H. L. and Tatel, H. E. 1959, URSI-IA U Radio Astron. Symp. Paris 1958, in press. MacRae, D. A. and Westerhout, G. 1956, Tables for the Reduction of Velocities to the Local Standard of Rest, Lund Observatory. Ohisson, J., Reiz, A. and Torg~d, I. 1956, Tables for the Conversion of Galactic into Equatorial Coordinates, Lund Observatory. Shain, G. A. 1957, Russian A. J. 34, 3. Department of Physics and Astronomy, University of Rochester, Rochester, N. V. Publication: The Astronomical Journal Pub Date: 1959 DOI: 10.1086/107982 Bibcode: 1959AJ.....64Q.128H full text sources ADS |