The Geometric Localization of STEREO CMEs

We describe a straightforward methodology for determining the location and other gross properties of CMEs within the coronagraph field of view in the upcoming STEREO mission observations. We use geometric triangulation upon a series of lines-of-sight taken from two spacecraft views that are locally tangent to the apparent edges of a CME. From the intersections of these lines-of-sight, we construct a set of stacked quadrilaterals that fully bound the structure and convey something of its location, shape, and size; a time sequence of such determinations can be used to determine the velocity. The technique is relatively robust and promises a substantial improvement in our capability to locate and characterize CMEs for research as well as forecasting purposes.