FILAMENT DISAPPEARANCES AND ASSOCIATED SHOCKS OF MAY 1979

In late May 1979 a shock was seen at each of two locations separated by about 90-degrees in heliolongitude and at about the same time. A shock was detected near the Earth, and a shock was detected at Helios 1 when it was off the Sun's west limb. Some authors have considered that these shocks were part of the same event, which originated with a filament disappearance near 65-degrees-W. We discuss the observations which show that a large complex filament, extending from 20-degrees-W to 70-degrees-W, disappeared in several Places, probably generating more than one shock. The shock detected near Earth was probably associated with a filament section which disappeared near the central meridian. If this is the case, then the interplanetary scintillation observations of this time period can be explained without invoking highly anisotropic shock propagation.