  An analysis of currently available ammonia (NH$_3$) visible-to-near-infrared
gas absorption data was recently undertaken by Irwin et al. (Icarus, 302 (2018)
426) to help interpret Very Large Telescope (VLT) MUSE observations of Jupiter
from 0.48 - 0.93 $\mu$m, made in support of the NASA/Juno mission. Since this
analysis a newly revised set of ammonia line data, covering the previously
poorly constrained range 0.5 - 0.833 $\mu$m, has been released by the ExoMol
project, "C2018" (Coles et al., JQSRT 219, 199 - 122, 2018), which demonstrates
significant advantages over previously available data sets, and providing for
the first time complete line data for the previously poorly constrained 5520-
and 6475-\AA\ bands of NH$_3$. In this paper we compare spectra calculated
using the ExoMol-C2018 data set (Coles et al., JQSRT 219, 199 - 122, 2018) with
spectra calculated from previous sources to demonstrate its advantages. We
conclude that at the present time the ExoMol-C2018 dataset provides the most
reliable ammonia absorption source for analysing low- to medium-resolution
spectra of Jupiter in the visible/near-IR spectral range, but note that the
data are less able to model high-resolution spectra owing to small, but
significant inaccuracies in the line wavenumber estimates. This work is of
significance not only for solar system planetary physics, but for future
proposed observations of Jupiter-like planets orbiting other stars, such as
with NASA's planned Wide-Field Infrared Survey Telescope (WFIRST).
