Observations and stereoscopic reconstruction of AR 12891 on 2021 November 2 at 00:59 UT. (a) Vertical photospheric magnetic field saturated at ±1 kG. Contours are drawn at ±0.75 kG. The main PIL is indicated by a black dotted curve. (b) Nearest-in-time AIA 304 Å unsharp-mask image. The path along which stereoscopic reconstruction of the height of the filament is performed is indicated by gray crosses (differentially rotated from the time of stereoscopic reconstruction at 2 November 01:05 UT). (c) Nearest-in-time AIA 94 Å image. (d) Stereoscopy-based estimate of the height of the filament (black diamonds) and associated uncertainty (gray-shaded area).