Evolution of target prominence-filament from 20:06 UT, December 22, 2011 until 21:06 UT, December 23, 2011, in SDO and Stereo_B spectral lines. Right column: composite images of 304 Å, 171 Å, and 193 Å lines from SDO_AIA, Left column: the 195 Å line of Stereo_B-EUVI. White arrows marked with , , and show the locations of prominence footpoints in both spacecrafts. Red dashed-curved lines show approximate boundaries of prominence, while the white dotted-curved lines in the lower right panel show the trajectories of coronal rain.