Rotational diagram of the first (top) and the second (bottom) components toward the MF1 peak, based only on data observed with a synthesized beam of 3.63″  ×  2.26″. Dots and squares with error bars mark detected and partially blended lines in the fundamental and first excited states v_t = 0 and v_t = 1, respectively, and filled triangles mark undetected lines and open triangles blended lines. The red line is the fit according to the method described in Sect. 4. The derived temperature is 119  ±  10 K and 168  ±  30 K, respectively.