Title:[0851] Comet Giacobini-Zinner Caption:U.S. Naval Observatory photograph of Comet Giacobini-Zinner Copyright: Credit:National Optical Astronomy Observatories

Title:[1184] Comet Kohoutek Caption:Comet Kohoutek photographed by Dr. Michael Belton on 28 November 1973, with the Schmidt telescope, Kitt Peak, near Tucson, Arizona. The imperfection visible in the photo is a flaw on the original plate and could not be avoided in reproduction. Copyright: Credit:National Optical Astronomy Observatories

Title:[0839] The principal parts of a comet Caption:The principal parts of a comet. The sublimation of frozen gases in the cometary nucleus forms the coma: the action of the sunlight and the solar wind draw out the dust and gas tails. Copyright: Credit:National Optical Astronomy Observatories