Tie pointing with the scc _measure3 routine applied to STEREO A (left panel), SDO (central panel), and SolO (right panel) images. Different parts of an extended prominence are triangulated with crosses in black, gray, and white, respectively. The white crosses in the STEREO A and SolO images correspond to the blue asterisk in the SDO image. The epipolar projections are very close together, and to better distinguish them, the epipolar line of STEREO A is plotted in dashed white and the SolO epipolar line in dashed black.