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Robert W. Hobbs (1938–2013)

Hobbs was a pioneer in the studies of the cm-mm radio emission and polarization of solar system, Galactic and extragalactic sources in the period 1960-1990. He became Branch Head of NASA Goddard Space Flight Center in 1976, where he guided investigations across the EM spectrum.

Published onOct 02, 2020
Robert W. Hobbs (1938–2013)

Courtesy of the Hobbs family.

Robert W. Hobbs died on Friday the 11th of January, 2013.

Robert Wesley “Bob” Hobbs was born January 18, 1938, in Chester, West Virginia, and passed away at his home in North Beach, Maryland. He graduated from Chester High School, received a bachelor’s degree in physics at Case institute of Technology in 1960, and earned a PhD in astronomy at the University of Michigan in 1964. Early in his career he displayed an interest in research in radio astronomy. While at Case he spent time at the Green Bank Observatory using the 85-foot telescope to study the HII region M17 at a wavelength of 3.75 cm under the guidance of Frank Drake. In graduate school at the University of Michigan, Ann Arbor, he co-authored papers on radio source polarization with his advisor, Fred Haddock. His PhD thesis, based on his interest on this topic, was “The Polarization of Radio Sources at 3.75 Centimeter Wavelength”.

Bob was a pioneer in the studies of the cm-mm radio emission and polarization of solar system, Galactic and extragalactic sources in the period 1960-1990. In the late 60s and 70s studies of radio sources at wavelengths as short as 1 cm were in in the exploratory phase. For example, the 140-foot telescope at Green Bank was completed in 1965.

Bob assumed a position at the Naval Research Laboratory after getting his PhD to follow his interest in radio astronomy. Jim Hollinger, who received his PhD from the University of Virginia, was also recruited at about the same time. Their common scientific research interest was radio variability and polarization of Galactic and extragalactic radio sources and QSOs, using the newly acquired 85-foot telescope at Maryland Point, NRAO’s 140-foot telescope and the Navy’s 150-foot Sugar Grove antenna. In 1967 Bob, as head of the cm/mm-wave radio astronomy section in the Radio Astronomy Branch at NRL, made early observations of the flux density and polarization of Galactic and extragalactic radio sources in the wavelength range spanning 0.33 to 3.75 centimeters. He was one of the first to observe at 4.3 mm wavelength using the Kitt Peak telescope in the late sixties using receivers fabricated at NRL.  

One of us (KJ) is grateful for Bob’s help in his early career at NRL. Bob was very generous in encouraging him to study HII regions, which was the topic of his NRC Postdoc fellowship.  Bob gave KJ, then a summer student, the opportunity to explore HII Regions with state-of-the-art instrumentation from project inception through observations, analysis, and publication. Bob encouraged the other summer students to pursue radio astronomy careers, making them coauthors of refereed papers based on observations they participated in at Maryland Point Observatory. KJ spent many hours observing with Bob and remembers many helpful conversations about the astrophysics of radio sources.

Hobbs left NRL in 1969 to join NASA Goddard Space Flight Center as a member of the Advanced Systems and Ground Observations Branch in the Laboratory for Astronomy and Solar Physics (LASP) and became Branch Head in 1976. There he was a welcome participant in multiple projects that made use of his expertise in electronics and instrumentation, besides continuing his research on radio sources at cm and mm wavelengths. He made radio observations of solar flares and active regions and led a GSFC effort to complete and put into operation a visible light solar flare spectrophotometer at Sacramento Peak Observatory. The latter entailed his living in a trailer on the Peak for one year, during which time he had the novel experience of a bear breaking into and trashing the trailer (fortunately when Bob was away). He managed the installation and test of a set of co-mounted telescopic SEC vidicon cameras for multi-band imaging photometry of the solar corona during total eclipses. Afterwards he participated in testing and observations of stellar and cometary observations with the GSFC SEC vidicon system at Kitt Peak, including studies of chromospheric lines in late-type stars with the McMath Solar Telescope (now called McMath-Pierce Solar Telescope) at KPNO.

In cometary work, an important focus of work at LASP, Bob helped develop the Joint Observatory for Cometary Research atop South Baldy near Socorro, New Mexico in preparation for the 1986 return of Comet Halley, helped manage NASA’s “Operation Kohoutek” and conducted radio interferometric observations in search of that comet’s icy-grain halo. This inspired him to develop later a proposal for a mm-wave radiometer to study a comet nucleus from a space probe, drawing on GSFC’s capabilities in both comet science and remote sensing of Antarctic and other terrestrial ice fields. In Bob’s further adventures along the electromagnetic spectrum at GSFC, he also worked on ultraviolet observations with the IUE satellite and on the analysis of infrared measurements of Mira variables with data from U.S. Air Force infrared satellites, prior to the launch of the first infrared astronomy satellite.

Bob left NASA for a management role in a commercial proposal for a new US air traffic control system and retired in 1992 at age 55 to pursue interests in gardening, keyboard and organ instruments, and community activities in North Beach, Maryland. He was a life member of the Organ Historical Society and was the organist at the Friendship United Methodist Church in North Beach from 1982–2009.

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