The Impact of Geometry on CME Observations Made by SEECHI

Optical observations of Coronal Mass Ejections (CME's) during the past several decades have generally been confined to events observed near the sun. Although events originating from most regions of the sun can be observed, the assumption has often made that the CME is propagating in the plane-of-the-sky. This assumption is generally adequate to give lower limits of CME mass and speed. However, continuous observations of CME's are now being made from very near the solar surface to large distances from the sun by the SECCHI instrument on STEREO. When CME's are observed at great distances from the sun, plane-of-the-sky assumptions are not adequate for analysis of these events. In this presentation we will discuss some recent observations made by the SEECHI instruments and the impact of geometry on our interpretation of these events.