A fluorescent equilibrium model for the 1-0 band of the A-X system of ${18}^{OH}$ has been constructed. Line positions and intensities have been calculated for possible future spectroscopic observations of these bands from space in order to derive ${18}^{O}/{16}^{O}$ ratios in comets. It is demonstrated that the strong lines of the 1-0 band can be observable for a moderately bright comet using a high resolution spectrometer with a reasonable exposure time.