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Richard B. Dunn (1927–2005)

Published onDec 01, 2007
Richard B. Dunn (1927–2005)

Dr. Richard B. Dunn, astronomer emeritus at the National Solar Observatory, died of a heart attack on September 29, 2005. He was recognized as one of the foremost experimental solar physicists. His innovative designs for telescopes and instruments led to many important discoveries in solar physics.

Born in Baltimore, Maryland, in 1927 and raised in Minneapolis, Minnesota, Dick's parents were Dr. Halbert L. Dunn and Katherine Brandner. Halbert (MD, Ph.D., F.A.P.H.A.) was an physician who became Chief of the National Office of Vital Statistics, Public Health Service. He published a paper "High Level Wellness for Man and Society" that became the founding paper of the field of wellness health care. After their divorce in 1942, Katherine moved to New York and became a social worker. Dick had two older brothers who died before him, Halbert (born in 1921, who became a civil engineer) and Robert (born in 1924, who became an architect).

Dick earned a BS in mechanical engineering and an MS in astronomy at the University of Minnesota. At the end of World War II he served in the United States Army in Japan. For his master's degree, Dick undertook the design and construction of a Lyot-type birefringent filter for observations of solar prominences. This early work led to his acceptance at Harvard, where Professor Donald Menzel encouraged him to continue his work with the 15-inch Cambridge telescope.

In 1951 he conducted part of his doctoral thesis work at the fledgling Sacramento Peak Observatory in southern New Mexico. The observatory director, Dr. John Evans, was impressed with Dick's outstanding instrumental talents and invited him to join as one of the first scientific staff members. During his first few years at Sac Peak, Dick developed two more birefringent filter systems including one with an integrated coronagraph. With this system, he produced the best prominence and spicule observations ever obtained.

Dick's career was dedicated to obtaining solar observations of the highest possible spatial resolution, having unparalleled quality that would reveal the underlying physics. Only by studying the small magnetic structures near the surface, he thought, could we understand such phenomena as the solar flares that periodically disturb the Earth. Many of his instruments were designed with this aim in mind and he was proven correct in the end.

Preeminent in Dick's achievements is the design concept for the Vacuum Tower Telescope, which was commissioned in 1969. It is a completely novel telescope that incorporates several daring engineering concepts. It was the first tower telescope with an evacuated light path, to eliminate internal seeing. It was one of the first to utilize an alt-azimuth mount, under computer control. Upon his retirement in 1998, the telescope was rededicated in his honor as the Richard B. Dunn Solar Telescope (DST).

In the DST, Dick pioneered the concept of the telescope as an integrated observing system; it was the first to incorporate telescope guidance and control and digital data recording operations in a single computer control system. Dick appreciated the advantages of such computer control a decade before the astronomical community generally accepted these concepts. His innovations led the way to similar advances in astronomy as a whole.

The DST achieved Dick's aim of providing high-resolution solar images and great flexibility in combining analyzing instruments. The DST continued as the preeminent high-resolution solar telescope in the world for the next three decades and remains a powerful and versatile system that allows simultaneous measurements using multiple cameras to record high-resolution imaging of solar features and activity, as well as high-sensitivity spectral, polarimetric and other kinds of data, and now incorporates a very effective adaptive optical system.

Another of Dick's major projects was the design of a U.S. Air Force network of solar telescopes. These five identical systems were deployed around the world to give continuous monitoring of solar activity. He was involved with many other instruments, projects and systems. Notable among these was the design of an early solar space telescope and pioneering work in solar adaptive optics.

Dick made several important discoveries with his novel instruments. His early narrow-band filter observations with the DST showed that solar spicules cover only a small area of the solar surface and reside mainly on the super-granule network. He discovered that photospheric magnetic fields emerge in kilogauss strength from sub-arcsecond "filigree."

Dick gained an international reputation for his design expertise and his willingness to help other astronomers. His advice and direct help were eagerly sought, and freely given. One can hardly visit any solar observatory in the world without hearing,"Yes, that was a Dick Dunn design." He was awarded the Hale Prize by the Solar Physics Division of the American Astronomical Society in 1998, "For his bold and imaginative innovation of instrumentation for solar physics, his discovery of important new phenomena on the Sun, and the impact of his contributions on solar physicists worldwide."

But Dick's life and work at the observatory constitute far more than simply that of a skilled experimenter who carried out new kinds of groundbreaking observations with his special instruments. He was the embodiment of those rare individuals with scientific instrumental skills who generate totally new types of systems, their work marked by extremely clever, creative and innovative ideas. In Dick's case, this profile was coupled with the ability to apply enormous energy, patience, commitment and enthusiasm to any instrumental challenge. Over the years his contributions advanced the careers of a whole generation of solar astronomers.

Dick died in his home in Las Cruces, New Mexico, after a long fight with Parkinson disease. Dick is survived by his wife of 55 years, Alice Dunn. Alice was very involved in music and had a beautiful voice. She did Russian translations, worked with the blind (which got Dick interested in developing the translator and printer mentioned below, and remains highly involved in the music scene in Las Cruces.

Dick was a person of many talents and interests, including music, sculpture and sailing, and for example, worked hard to develop an automated Braille translator and Braille printer. He was fascinated with renaissance musical instruments, acquiring a substantial collection, which he later donated to the El Paso Symphony Orchestra. He achieved much enjoyment from his hurdy-gurdy, happily entertaining anyone within earshot! Dick built several musical banks that would play elaborate tunes when a coin was inserted. The coin then rolled along ramps, striking a note each time it fell to the next level, with the length of the ramps determining the timing between notes.

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