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
Rings of Saturn has been attributed to a perturbation caused by impact of material from Comet Shoemaker-Levy 9 in 1994. The C Ring is a wide but faint ring located inward of the B Ring. It was discovered in 1850 by William and George Bond, though William R. Dawes and Johann Galle also saw it independently. William Lassell termed it the "Crepe Ring" because it seemed to be composed of darker material than the brighter A and B Rings. Its vertical thickness is estimated at 5 m its mass at around 1.1 kg, and its optical depth varies from 0.05 to 0.12. That