Rotational diagrams for NH₃, ¹⁵NH₃, CH₃OCHO, SO₂, and CH₃OH. The circles and squares are explained by the legends in the upper right of each panel. A calibration error of 20% has been included in the error bars. In the NH₃ panel, least-square fits to J + 1, J + 2, J + 3, and J + 4 are indicated by a red dashed line, a red dotted line, a red dot-dashed line, and a red solid line. In the ¹⁵NH₃ panel, the para and ortho transitions of ¹⁵NH₃ are black and blue; the least-square fits to para and ortho metastable ¹⁵NH₃ transitions and non-metastable ¹⁵NH₃ transitions are indicated by a red dashed line, a red dotted line and a red dot-dashed line, respectively. In the CH₃OH and CH₃OCHO panels, the dashed and dotted lines represent fits to A type and E type transitions, respectively. In the SO₂ panel, dashed and dotted lines represent fits to its plateau and its HC component.