Rotational diagrams of various transitions of the N = 1 → 0, 3 → 2, and 5 → 4 transitions of C₂H (top row); J = 2 → 1, 6 → 5, 7 → 6, and 8 → 7 transitions of ortho c-C₃H₂ (top and bottom rows); and J = 2 → 1, 7 → 6, and 8 → 7 transitions of para c-C₃H₂ (bottom row) observed toward Her 36. For C₂H, rotational diagrams are plotted with an assumption of optically thin C₂H (in red) andincluding the optical depth correction factors (in blue). Fitted values of rotational temperatures are given for each molecule. The error bars were calculated from the maximum noise of the integrated intensities of individual transitions and from calibration uncertainties of 20%.