Top row: Separate observed events through different satellites. Top-left: White-light image from STEREO-A Cor2 of an erupting filament, displaying a clear circular pattern. Top-right: Different event as observed with SDO/AIA in the 304 Å channel, also showing a clear circular pattern. Bottom row: Synthetic images for the σ = 2 case at instrument resolution. Bottom-left: 304 Å channel. Bottom-right: 193 Å channel. Blue and white arrows indicate dark structures, also marked by dashed lines of the same color, which correspond to features analyzed in Fig. 13. Observational images are from the AIA Filament Eruption Catalog.