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We thank the referee for the careful and thoughtful examination of our
article.  We particularly appreciate the suggestion to reduce the
number of figures and remove those that are superfluous.  We have
removed the various scatter plots and replaced them with plots of the
radial run of the important effects, along with two plots showing the
radial run of the derivative of the smear compared with the
astrometric residuals and the derivative of the astrometric residuals
compared with the flat-field features.  We have also removed the
5-filter panels for the astrometric, flat-field, smear, and shear
effects.  We instead adjust the discussion to focus on the single
figure with all 6 effects shown for r-band.  We have adjusted the
wording to account for the change in the figures.

Below are our point-by-point responses to the {\tt referee's suggestions}.

\begin{verbatim}
Figures: there are substantially more than are needed; I don't think you need
to show every band of every effect in Figs 3,4,5, and 6 - Fig 7 is by far the
most informative, allowing comparison of your diagnostics. Similarly, showing
all the scatter plots for all bands in Figs 8,9,10,11,12 is overkill, in my
view. I'm not sure any of these x vs y scatter plots are really needed; for me
it suffices to give the amplitudes of each effect relative to g band in
tabular or graphical form. The most important figure that I would want to see
is, in fact, missing: a plot of the radial run of each effect (a 1d plot of
Fig 7, basically), so that I can e.g. visually see whether the flat field is
the derivative of the astrometric displacements, as the lateral-field model
predicts.
\end{verbatim}

This is a good point.  We have greatly reduced the number of plots,
removing the 5-filter images in Figs 3,4,5,6 (astrometry, flat-field,
smear, shear) and the scatter plots for figures 8-14.  We have
replaced these with 3 new figures: one showing the radial run of the 4
effects with significant tree-ring patters (smear, psf mags,
flat-field, and astrometry) as suggested; a second plot showing the derivative
of the smear and the astrometry; a third plot showing the derivative
of the astrometry with the flat-field.  We feel these new plots make
the relationships between the different trends much clearer than the
scatter plots.  

\begin{verbatim}
Also the spacing of the arrows in the ellipticity figures is too coarse to see
whether there are radial shear variations that are coherent with any of the
ring patterns. Here a 1d radial plot would be essential.
\end{verbatim}

We disagree : the arrows are only showing the direction; the image in
the background shows the amplitude of the ellipticity variations,
which are completely dominated by the large-scale (optical) effects.
The resolution of the image is sufficient to follow the tree rings,
but there is no signal matching that pattern.

\begin{verbatim}
page 4, Line 18: "non-pixel uniformity" ??
\end{verbatim}

Changed the wording to be clearer. 

\begin{verbatim}
4/22: "relatively coarse grid" - can you give the grid size?
\end{verbatim}

Added the grid size.

\begin{verbatim}
4/36: Can you say whether there are any differences between the "PV2 analysis
discussed here" and the public data releases, i.e. corrections that this work
implies need to be made to the public data?
\end{verbatim}

Added a sentence about this.

\begin{verbatim}
5/12: "diffusive effects of the lateral fields" - the lateral fields effects I
would not consider "diffusive" since they simply are conducting the charge
packets in a tranverse direction. The effect you find dominating the PS1
devices differs in being primarily diffusive.
\end{verbatim}

True, we mean charge motions or migrations caused by the lateral
fields.  We've reworded this to be more accurate.

\begin{verbatim}
Table 1, 8/13, other places: these values are referred to as the "per-pixel
standard deviations" which is unclear to me. Is this the SD of different
stellar measurements or flat-field pixels contributing to the mean of a given
super-pixel in the plots? Or is it the SD of the super-pixel averages, i.e.
the SD of the plotted values? Or something else? The most relevant statistic
is the SD after the shot noise of the individual measurements has been
suppressed, since we don't care about measurement noise in this paper.
\end{verbatim}

This referred to the standard deviation of the pixel values in the
superpixel images.  In retrospect, this table did not add much useful,
so we've removed it and changed the wording in the text to be clearer.

\begin{verbatim}
Fig 1: In the caption it would be good to state that this is for one device in
the camera (even though this is stated in the text).
\end{verbatim}

Done.

\begin{verbatim}
Figs 1,2, 4: Why does Y band have so many missing (white) pixels?
impossible to look for patterns.
\end{verbatim}

The effect from y-band fringing is much larger than the relevant
effects, saturating the dynamic range of the color scale.  Added
wording to the captions to explain.

\begin{verbatim}
Fig 3: what are the units of the plot?
\end{verbatim}

This figure has now been removed; the text gives the dynamic range for
all 6 sub-figures in the r-band figure showing all effects.

\begin{verbatim}
Table 2 (and in text in many places): you talk about "correlations" between
filters or different effects, but my guess is that what you are really
plotting is the amplitude of variations relative to those in g band. The
correlation coefficient would be something different - and less interesting,
since the correlation coefficient will depend heavily on size of irrelevant
sources of variation like measurement noise and the g-band striping. A graph
of these values (grizY along the x axis, different symbols for each effect)
might be more effective than this table.
\end{verbatim}

This is correct.  The table shows the relative amplitudes of the
effects.  We have replaced this table with a plot of the relative
amplitudes of the 4 effects which show the tree-ring patterns.

\begin{verbatim}
Table 3: same comment, what does "correlation" mean here?
\end{verbatim}

Again, the is the relative amplitude of the effects compared with
g-band.  Along with Table 1, we have decided to remove this table.
The conclusions of the paper are not dependent on the relative
amplitude of the effects, except to the extent that the blue filters
show stronger effects than the red filters.   

\begin{verbatim}
11/9: "deviations relative to the median flat-field image" - do you mean that
you are plotting the deviations relative to the median *of* the flat-field
image? Otherwise I don't understand.
\end{verbatim}

Correct.  The wording is fixed.

\begin{verbatim}
11/25: A Gaussian smoothing of 3 superpixels - is this well above the max
"wavelength" of the rings? If not it can suppress a lot of them. Seems small
compared to the features visible in some of the figures.
\end{verbatim}

This smoothing scale is large enough that it does not suppress
significantly the tree-ring features; without the smoothing, some of
the brick-wall pattern remains.  The wording has been updated to clarify.

\begin{verbatim}
Fig 14: what are the red and blue lines?
\end{verbatim}

This figure has been removed and the information replaced with the new
Figure 6. 

\begin{verbatim}
24/19-21: These statements seem contradictory: the slope should be -1; the
data give a slope of 0.5; they are consistent.
\end{verbatim}

The best-fit slope was actually $\sim -0.5$, with errors large enough
that it was consistent with -1.0: the missing minus sign was a typo.
However, we had a sign error in the calculation of the
proportionality; with the correct definition, the proprotionality is
positive.  However, the noisy measurement of the slope was not very
informative.  Referring to the new Figure 6, it is clear that that the
derivative of the astrometric variations is roughly proportional to
the flat-field variations.  The point of this portion of this
discussion is simply that the astrometry and flat-field variations
behave in the way we would expect if they were caused by the lateral
charge migration effect, and thus this is a plausible explanation for
those observed effects.

We have reworded the text to be clearer about this.

\begin{verbatim}
24/23, 25/28, 25/30: Here you should probably be referring to DECam (the
camera) rather than DES (the survey).
\end{verbatim}

Fixed.

\begin{verbatim}
25/17: Is there any concise way to explain why adding dopants (space charge)
will *decrease* the transit time and charge diffusion at fixed voltage and
distance across the device?
\end{verbatim}

The increased space charge increase the electric field in the device
for a fixed applied voltage, thus increasing the migration speed.
The description has been somewhat clarified.

\begin{verbatim}
Conclusions: you should probably say something about which published
quantities of the PS1 catalogs are affected by this effect, by how much, and
whether any corrections have been applied, whether the effects are reduced by
averaging over multiple exposures.
\end{verbatim}

Done.  

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Eugene Magnier \\
Specialist / Astronomer \\
Pan-STARRS IPP Lead \\
IfA / Pan-STARRS \\
University of Hawaii

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