John Elsworth Merrill (1902–1991)

John Merrill died on November 29, 1991 in Columbus, Ohio as a result of complications following a leg amputation made necessary by extreme peripheral vascular disease. He had been incapacitated by this condition for a number of years.

Merrill was born on May 10, 1902 in Parsonsfield, Maine. He received a Master's degree in Greek from Boston University in 1923, a Master's degree in mathematics at Case Institute of Technology in 1927. He then earned a Master's degree in mathematics at Princeton University in 1929, followed by a Ph.D. in astronomy in 1931.

After serving as curator at the Buffalo Museum of Science from 1932 to 1936, he occupied various academic level positions leading to an associate professorship at Hunter College in New York City in the period 1937 to 1950. He then moved to Delaware, Ohio where he served as associate professor and professor jointly at Ohio Wesleyan University and Ohio State University until 1959. The following four years were spent at the Franklin Institute in Philadelphia as an engineer and scientist. He then accepted a professorship in astronomy at Central Methodist College in Fayette, Missouri, from which he retired in 1969. He spent the following years as a visiting professor of astronomy at the University of Florida, where he became an adjunct professor in 1980.

John Merrill was one of Henry Norris Russell's many great admirers and disciples, which led him, during the period 1943 to 1963, to spend much time at Princeton as a visiting professor and research associate. In his studies of the external properties and internal constitution of stars, Russell recognized that particularly important information could be obtained on their radii, masses and luminosities from a study of eclipsing binary systems. Since one needs to determine many parameters from an observed light curve (including those relating to the orbital elements and to the stars themselves, including ellipticity, limb darkening and reflection), Merrill and Russell were led to make many contributions to the theory and practice of such analyses. Their joint efforts culminated in their Contribution No. 26 from the Princeton University Observatory published in 1952. This was accompanied by extensive numerical tables and nomographs for use in making the solutions. Constructing the tables required prodigious calculations (given the primitive calculators of that era) by Merrill and his coworkers. This work earned Merrill the status of a leading expert in eclipsing binary studies, in recognition of which he served as president of Commission 42 of the International Astronomical Union from 1961 to 1967.

At Hunter (then a women's college) John Merrill was known as a professor whose lectures were engrossing, whose courses were fascinating, who was truly interested in his students, and one of a few who invited them to his home. He taught elementary and intermediate astronomy, variable stars and astrophysics. He encouraged students to attend AAS meetings and was somewhat abashed that some of his colleagues teasingly called them Mother Merrill's Chickens.

Merrill hired National Youth Administration students to work on his numerical tables, but he also had volunteers who did the calculations for the sheer pleasure of working for him. At the 50th reunion of the Hunter College Class of 1941, some ten or more 70-year-olds talked about John Merrill's being the best teacher they ever had. Several of them were still in touch with him.