  The calcium monohydroxide radical (CaOH) is an important astrophysical
molecule relevant to cool stars and rocky exoplanets, amongst other
astronomical environments. Here, we present a consistent set of highly accurate
rovibronic (rotation-vibration-electronic) energy levels for the five lowest
electronic states ($\tilde{X}\,^2\Sigma^+$, $\tilde{A}\,^2\Pi$,
$\tilde{B}\,^2\Sigma^+$, $\tilde{C}\,^2\Delta$, $\tilde{D}\,^2\Sigma^+$) of
CaOH. A comprehensive analysis of the published spectroscopic literature on
this system has allowed 1955 energy levels to be determined from 3204
rovibronic experimental transitions, all with unique quantum number labelling
and measurement uncertainties. The dataset covers rotational excitation up to
$J=62.5$ for molecular states below 29\,000~cm$^{-1}$. The analysis was
performed using the MARVEL algorithm, which is a robust procedure based on the
theory of spectroscopic networks. The dataset provided will significantly aid
future interstellar, circumstellar and atmospheric detections of CaOH, as well
as assisting in the design of efficient laser cooling schemes in ultracold
molecule research and precision tests of fundamental physics.
