Averaged 18 cm OH lines of 12 P observed on three separate days: January 20 (left), March 2 (middle), and March 3 (right), 2024. Top and middle: 1665 and 1667 MHz lines, respectively. Bottom: weighted averages of the 1667 and 1665 MHz lines scaled to 1667 MHz, assuming the statistical ratio of 1.8. The vertical scale is the main beam brightness temperature, and the horizontal scale is the Doppler velocity in the comet rest frame. The frequency resolution is 0.0014 MHz, corresponding to a velocity resolution of 0.2575 km s⁻¹ after smoothing. We list the fitting results in Tables 3 and 4.