Examples of high excitation transitions of 3-hydroxypropenal that have been significantly shifted with the new spectroscopic study. Models obtained with previous spectroscopy are indicated in blue (T_ex = 300 K) and green (T_ex = 125 K). The new models are in red (T_ex = 300 K) and magenta (T_ex = 125 K). The column densities are N = 1.0 × 10¹⁵ cm⁻² for T_ex = 125 K and N = 1.8 × 10¹⁵ cm⁻² for T_ex = 300 K. An absorption due to a nearby bright line is present around 343.14 GHz. The cyan dotted line represents the 3 rms level per 0.33 km s⁻¹ (1/3 of the line width).