Heidi Hammel improvements to the adaptive optics systems of the Keck telescope, astronomers became able to capture "unbelievably crisp images" and view many details that could not be seen before. Hammel's planetary research with Hubble and Keck has demonstrated that both Uranus and Neptune are dynamic worlds. Hammel primarily studies the outer planets and their satellites, focusing on observational techniques. She was a member of the Imaging Science Team for the Voyager 2 encounter with the planet Neptune in 1989. In 1994, Hammel led the team that investigated Jupiter's visible wavelength response to the impact of comet Shoemaker-Levy 9 using the Hubble
David H. Levy biography of Pluto-discoverer Clyde Tombaugh in 2006, and his tribute to Gene Shoemaker in "Shoemaker by Levy". He has provided periodic articles for "Sky and Telescope" magazine, as well as "Parade Magazine", "Sky News" and, most recently, "Astronomy Magazine". Periodic comets that Levy co-discovered include 118P/Shoemaker–Levy, 129P/Shoemaker–Levy, 135P/Shoemaker–Levy, 137P/Shoemaker–Levy, 138P/Shoemaker–Levy, 145P/Shoemaker–Levy, and 181P/Shoemaker–Levy. In addition, Levy is the sole discoverer of two periodic comets: 255P/Levy and P/1991 L3. On February 28, 2010, Levy was awarded a Ph. D. from the Hebrew University of Jerusalem for his successful completion of his thesis "The Sky in Early Modern English Literature: A Study