“…Fifty interferogram s were collected for each of these three con gurations. This procedure was repeated at each step as the blackbody temperature was lowered to 45,40,35,30,29,28,27,26,25,24,23,22,21,20,15,10, and 5 8C. The data collection was then completed by raising the temperature to two nal settings of either 25.5/50, 18/32, 18/31, 24.5/25.5, or 18/50 8C.…”