Networking ground-based images of comet Halley during the Giotto encounter



Comets are renowned for their rapid evolution and for unexpected changes in their structure and brightness, particularly when they are within the inner part of the solar system. Because of this, up-to-date information on the development of the gas, dust, and ion production rates and of the ion tail structure of Comet Halley was required by scientists involved in the European Space Agency (ESA) Giotto mission throughout the spacecraft encounter period. It was obvious that images of the 1910 apparition, from the preperihelion period, or even from a week prior to encounter, would not be representative of the structure and activity during the encounter.