My work has primarily involved observation and modeling of comets. While at the University of Iowa, a scanning filter photometer was used to obtain absolute intensity profiles for several comets, which were compared to theoretical profiles found with a numerical simulation for the emission and motion of dust and gas from a cometary nucleus. This allowed constraints to be put on several of the dust and gas parameters. The model also includes the interaction of the fluctuating interplanetary magnetic field with the charged dust particles, and was initially used to find dust particle impact rates to compare with the results of the flybys of comets Giacobini-Zinner and Halley.