CO Editor

Suggestions for revision or reasons for rejection

Review of revised manuscript of "Optimising hydroxyl airglow retrievals from
long-slit astronomical spectroscopic observations" by Christoph Franzen et al.

The new version of the paper has significantly improved in comparison to the
previous submission. For the latter, I sent a long list of comments since the
short paper did not discuss the approach and the results in a satisfying way.
Overall, my comments have been answered thoroughly. The related changes in
the paper have improved the comprehensibility and have led to a more careful
and balanced discussion of the results. The latter is important since the
discussion is only based on three spectra in different near-IR bands with
exposure times of 10.8 s. Therefore, it is out of the scope of the paper to
provide conclusions on the quality of OH-based temperature gradients,
especially if non-LTE effects cannot be handled. The focus should be on the
description of the available data, their processing, their analysis with
respect to OH emission, and an overview of the scientific questions that can be
studied under consideration of the possible limitations. The new manuscript
sufficiently fulfils these criteria. Hence, the paper can be published in AMT.
However, for this, I have a few, mainly technical, comments, which should be
considered first.

Abstract: Despite the major changes in the text, the abstract is still the same
(except for a single word). Please check carefully whether the current abstract
still agrees with the rest of the paper. For example, note that the reported
error of about 0.5 K is smaller than all uncertainties in Fig. 5. The best
accuracy seems to be 0.7 K, which was achieved for OH(5,3). The uncertainties
for the other bands appear to be significantly larger.

P. 3, L. 13 and P. 5, L. 28: In the response to my comments, it was stated that
the observed astronomical object is not a (telluric) standard star. However,
the confusing term is still used in the paper at two positions. In astronomy,
standard stars are only observed for data calibration and processing.

P. 5, L. 21 and P. 14, L. 2 (Fig. 3): The rotational temperature for the
OH(5,3) band has changed in Sect. 3.1 but not in the caption of Fig. 3. This
discrepancy has to be corrected. If I interpret the response letter correctly,
the change is related to a modified approach for the relative flux calibration.

P. 6, L. 27: The most critical molecule for the absorption of OH(8,6) lines in
the lower atmosphere is CO2. There are no CO lines in the relevant wavelength
regime.

P. 14, Fig. 4: The caption of this figure has improved. However, it could be
even better if it was directly stated that the labelled tickmarks only provide
rough positions of the corresponding lines.

Interactive discussion

Peer-review completion