Wulff Dieter Heintz, Professor Emeritus of Astronomy at Swarthmore College, passed away at his home on 10 June 2006, following a two-year battle with lung cancer. He had turned seventy-six just one week earlier. Wulff was a leading authority on visual double stars and also a chess master. A prominent educator, researcher, and scholar, Wulff was noted for being both succinct and meticulous in everything he did.
Wulff Heintz was born on 3 June 1930 in Würzburg (Bavaria), Germany. Naturally left-handed, his elementary school teachers forced him to learn to write "correctly" using his right hand, and so he became ambidextrous. During the 1930s, Wulff's family saw the rise of Adolf Hitler and lived under the repressive Nazi regime. As a teenager during World War II, Wulff listened to his family radio for any news from the outside world. He used to say that he loved the blackouts during the bombing runs because it made it much easier to see the stars. On the night of 16 March 1945, Wulff's home town of Würzburg was heavily bombed, resulting in the destruction of eighty-five percent of the city and the deaths of several thousand civilians. One incendiary bomb landed on the roof of his family home, but Wulff climbed up to the roof and extinguished it before the flames could spread. The next morning, he discovered (with some delight) that his high school had burned to the ground. As Germany continued to suffer massive losses, teenage boys as young as fifteen were inducted into the military and sent off to replenish the troops. To avoid an uncertain fate, Wulff hid out in a farmhouse in the countryside outside of Munich. When the allied troops invaded Germany in 1945, Wulff volunteered to be a translator between the American and British soldiers and the local villagers. In return for his valuable service, the soldiers taught Wulff how to smoke cigarettes, a habit that he continued until his final days even after having been diagnosed with lung cancer.
Shortly after the war ended, Wulff enrolled at Würzburg University, eventually completing his studies in 1950 with two majors, mathematics and chemistry. In 1950 he enrolled for graduate studies at Munich University. Conditions were horrid and austere, and the students were undernourished. Most of the university buildings had been destroyed during the war, but the buildings and domes of the Munich-Bogenhausen Observatory, which housed the meridian circles and the telescopes, suffered only minor damage. Lectures in astronomy were given in one of the small, surviving buildings on a tiny blackboard, forcing the lecturer to hold the chalk in his right hand and a sponge simultaneously in his left hand. Deplorable circumstances notwithstanding, Wulff, along with fellow classmates and future colleagues Edward Geyer, Theodor Schmidt-Kaler, and Joachim Herrmann, received a thorough instruction in astronomy from, among others, Hans Bucerius (celestial mechanics and theoretical astronomy), Wilhelm Rabe (binary stars), Erich Schoenberg (photometry, general astronomy), and Felix Schmeidler (astrophysics and galactic astronomy). Wulff also gained practical training in meridian circles and position micrometers, and learned to make binary star observations with the old Fraunhofer refractor (1835) of the Munich Observatory. It was here that his passion for binary stars was born.
In 1953, Munich University awarded Wulff the degree of Doktor rerum naturalis in astronomy, which he completed under the direction of Felix Schmeidler. Wulff was almost immediately recruited by the Munich University Observatory to serve as the Scientific Assistant at the Southern Station in Mount Stromlo, Australia. He worked at Mount Stromlo from 1954 to 1955, then returned to Munich to serve as Research Officer from 1956-69, during which time he visited both the United Kingdom and the United States. Wulff was involved in observations of the planet Mars, and in particular the dust storms that were occurring on that planet around the time of the 1956 opposition. His sketches of the Red Planet were quite detailed, and showed then unknown surface features which spacecraft visiting the planet years later revealed to be large volcanoes.
In 1960, Wulff published an early but substantial paper, "Die Doppelsterne im FK4," which was very important in the construction of the FK4 and was still used in 1988 for the FK5. Subsequently, in 1961, he was invited to attend the IAU Symposium on Visual Double Stars at the University of California, Berkeley. The experience was inspirational and solidified Wulff's devotion to double star research. By the end of the decade, in 1969, he published the results of an extensive statistical study of binary stars in a classic paper which became a much referenced contribution to the field.
On 14 June 1957, Wulff married Dietlind (Linde) Laschek, and the couple spent their honeymoon at the Royal Greenwich Observatory at Herstmonceux Castle in England. The marriage produced two children, a daughter Ruth, born in 1965, and a son Robert, in 1967. Wulff earned a Privatdozent (advanced postdoctoral degree) at Technological University Munich in 1967. Shortly thereafter, he accepted an invitation from Professor Peter Van de Kamp to come to the United States as a visiting astronomer at Swarthmore College, located outside Philadelphia. Wulff joined the Department of Astronomy permanently as an Associate Professor in 1969, and moved his family from Germany to the United States the following year. Wulff became Chairman of the Department in 1972 and served in that capacity until 1982. Wulff was promoted to the rank of Professor in 1973, and was a full-time faculty member at Swarthmore until his retirement in 1998. Wulff continued to teach introductory astronomy courses as an adjunct professor at nearby Widener University until 2005.
Over his long and distinguished career, Wulff Heintz pursued numerous research interests, including fundamental astrometry, stellar statistics, planetary studies, radial velocities, and, in his last years, monitoring slow variable stars using a CCD detector. Together with the committed staff of the Sproul Observatory, Wulff determined about 800 precise trigonometric parallaxes of mostly faint, high-proper motion stars. The lion's share of his attention over the period 1954-97 was devoted to double and multiple stars, orbit theory, and relative astrometry. An assiduous observer, Wulff logged many hours at the 24-inch Sproul refractor, striving to equal or better the record for total number of observations by a single observer set by William Herschel at the beginning of the nineteenth century. Over several decades, Wulff made a total of 54,000 micrometer measurements of double stars and discovered over 900 new pairs. Some of his resolutions of new binaries have only been confirmed with speckle interferometry or by the Hipparcos satellite. In fact, in the latter case, several of the "new" binaries resolved by Hipparcos had actually been previously resolved by Wulff years earlier.
As a dynamicist, Wulff had unquestioned skill in the calculation and analysis of binary star orbits. He fully employed both micrometry and photography, and also incorporated published spectroscopic data to calculate orbits for some 500 binary systems. He tackled some of the most complex systems which can be unraveled — astrometric systems where the secondary or tertiary is hidden and can only be disentangled by careful analysis of available observations. His prolific calculation of binary star orbits earned him the title of the "Swarthmore Orbit Machine" among some of his colleagues. Historically, only W.H. van den Bos made more observations of pairs than Wulff. Before the advent of interferometry the highest quality observations of the closest pairs were made by Wulff and his collaborator Charles Worley at the USNO. Wulff and Charles both concentrated on the closest pairs. These were not only the most difficult to split but also astrophysically the most important, because from these faster moving systems one could calculate orbits and in some cases determine masses. Wulff and Charles collaborated in the Fourth Catalogue of Orbits of Visual Binary Stars, (US Naval Observatory, 1983), the last paper version of this catalogue and a standard reference for many years. Even the more recent versions of the catalogue list more orbits by Wulff than by any other calculator.
Wulff was the author of some 150 research papers, plus several articles in the popular literature and encyclopedias. He was the author, co-author, or editor of nine books. His early monograph Doppelsterne (Goldmann, 1971) was recrafted and translated into English to become Double Stars (D. Reidel, 1978). This was the standard binary star text for many years and continues to serve as the definitive text on the subject. Those familiar with Wulff's style of writing will know why it was referred to as the "Terse Tome," but it contained all relevant information. Wulff collaborated with one of us (Augensen) to translate the German Handbuch für Sternfreunde into the English Compendium of Practical Astronomy (Springer-Verlag, 1994).
In addition to his professional pursuits, Wulff was an acknowledged chess master, and he authored Das praktische Schachbuch (Practical Chess Book), which had thirteen printings in the period 1968-1981. He was also an adept pianist, and was especially fond of playing Chopin, Liszt, and Rachmaninov.
Wulff's role as an educator was no less significant. Wulff enjoyed teaching courses at all college levels. As a lecturer for the Harlow Shapley Lecture Program of the AAS, Wulff visited a number of smaller colleges and universities across the U.S., delighting audiences with his wit, charm, and knowledge. One of Wulff's favorite activities was running the public viewing sessions at Sproul Observatory, in which he used the large 24-inch refractor to observe the moon, planets, double stars, nebulae, and star clusters. He ran special telescope sessions for Cub Scouts, Brownies, church groups, and amateur astronomical societies.
A truly international scholar, Wulff was a member of the Astronomische Gesellschaft, the American Astronomical Society, and a Fellow of the Royal Astronomical Society. Between 1979 and 1985, he served as president of IAU Commission 5 (Documentation and Astronomical Data) and on the executive committee of the International Council on Scientific and Technical.
Wulff is survived by Dietlind, his wife of forty-nine years, his daughter Ruth and son Robert, and his two sisters Monika Heintz and Ursula Heintz-Eberlein, who both live in Germany. After having lived a career which was so rich and productive, Wulff will be much missed by the astronomical community, and especially those working in the areas of astrometry and binary stars.