Review of Gemini MBC images submitted to PDS by H. Hsieh and M. Knight

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Documentation

  -Does the dataset contain all documentation needed to use and
   understand its data without prior knowledge?

The RA/Decs in the target_table*.txt documentation look to be the
predicted position of the asteroid at the time of observation.  These
should be updated to the measured position, which looks to be slightly
different in some cases (e.g. 288P/2006 VW139 (300163) in
n20161229.086. Additionally, the RA should be given to 1 decimal point.

  -Is the provided documentation well organized, clear and
   self-consistent?

Generally yes. Two problems I identified in overview.pdf: 1) The
description of RA and Dec should include whether they are of the
center of the FoV, or of the comet that was targeted. 2) The
description of the antiSolarPA and helioVelPA should specify that they
are in degrees East of North. Also, the helioVelPA is the *negative*
of the heliocentric velocity vector (and thus the expected direction
of the dust tail); Table 1 in overview.pdf states the opposite.

Also note, the FITS headers for Gemini-South have the following line:

TELESCOP= 'Gemini-South'       / Gemini-North

This header line is automatically produced by Gemini/GMOS, so I
wouldn't expect the PDS submitters to correct this, but it is worth
noting.  And maybe letting someone at Gemini know.


  -Can the dataset be understood without any external documentation it
   references, or should the information in said external references
   be incorporated into the dataset?

The wavelength and bandpass of the r filter should be added just
to ensure it is documented here, but otherwise yes.

  -If reviewing calibrated data, does the documentation fully explain
   the calibration process and contain all necessary parameters needed
   to repeat it?

Yes, and the bias/flat files are included

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PDS Labels and Meta Data

  -Are the descriptions and scientific content contained inside the
   PDS labels sufficient to understand their corresponding data
   products?

The units on the following PDS labels are incorrect, they should be deg for all images, not arcsec
            <geom:right_ascension_angle unit="arcsec">179.85838484</geom:right_ascension_angle>
            <geom:declination_angle unit="arcsec">12.77548204</geom:declination_angle>


  -Is all significant meta data included directly in the PDS labels?

Yes


  -Do the labels provide all essential description of data values
   directly in the label, instead of deferring them to external
   references or documentation?

Yes

  -Can the data be read programmatically using only the information
   contained in the PDS labels?

Yes, the images can be read by DS9 and the PDS4 viewer tool

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Data

  -Does the data look physically reasonable when examining it by eye
   or via a display tool?

Images look as expected for GMOS imaging.


  -When displaying the data as plots or images, are there any
   unexpected deviations?

The Gemini-S target_table*txt files have 158 lines, but only 134 data
sets are included in the repository. It appears the chip2 images for
2017-09-17, 2017-10-26, 2017-11-17, 2017-12-18, and 2017-12-22 are
missing from the data directory.  These do not appear in the
inventory.csv file.


  -Formulate a scientific inquiry and attempt to use the data to
   answer the inquiry.

I am interested in knowing if the tail material of Main Belt comets is
made of gas, fine grain dust, or large dust particles.  I opened
images from Gemini-N, choosing an object that was post-perihelion and
close to the Sun to increase the likelihood it would show activity.
In this test, I used the images of 324P from 2016-08-10. the target
table documentation provided me with the anti-Solar position angle as
well as the heliocentric velocity angle.  By plotting these vectors on
the image (once I confirmed that they were in degrees East of North,
which is different from the native units DS9 uses) I was able to see
that the tail was between these two vectors, implying it is made of
moderately sized dust grains.  A similar analysis of the tail of 238P
from the 2017-01-26 images indicates that this tail is mostly gas and
very fine dust.


  -If reviewing both raw and calibrated data, attempt to calibrate a
   raw data file.

N/A, calibrated data only was provided