Data Set Overview
=================
NEAR EDR volume sets contain a single data set, from one instrument
and one mission phase (defined in the phase table in /AAREADME.TXT).
 
The first volume of the set is a documentation-only volume and contains
CALIB, GEOMETRY and other non-data subdirectories. The INDEX directory
on the first volume contains the summary of all the volumes. The DOCUMENT
directory on the first volume contains non-changing documentation.
Subsequent volumes contain only BROWSE, CATALOG, DATA, and INDEX
subdirectories in order to minimize duplication.  The data volumes also
contain a DOCUMENT directory, which contains information related to the
calibration of the data files on that volume.
 
 
Directory/Product Description:
------------------------------
All images and image products described below are 537 x 244
rectangular pixels where the rectangular pixel dimensions are
162 x 96 microradians.
 
RAW: Raw images. Image in this directory are units of raw DN, as
received from the spacecraft after data were uncompressed. No editing
of the data has taken place. Missing transfer frames are represented
as null pixels.
 
RAD: Radiance images. Images in this directory have been calibrated
to units of radiance using the following procedure. Dark current was
removed using a model based on position in the image, mission-elapsed
time, exposure time, and CCD temperature. Frame transfer smear was
removed using the procedure described in MSICAL.TXT. The image was
then divided by the flat-field image corresponding to the filter
through which the image was taken. To convert from these units of
'corrected DN' to radiance, the image was divided by its exposure
time, a calibration coefficient (which converts from DNs/time to
radiance) for that filter, and the temperature dependence of the
calibration coefficient as described in MSICAL.TXT.
 
CRD: Cleaned radiance images. Images in this directory have been
calibrated to units of radiance using the following procedure. Dark
current, background frame transfer smear, and background leaked light
were removed using the nominal image and one taken with a 0-ms
exposure within several seconds, through the same filter. The 0-ms
exposure has a slightly different dark current but the same frame
transfer smear and leaked light. Dark current was removed separately
from the two images, using a model based on position in the image,
mission-elapsed time, exposure time, and CCD temperature. The
dark-corrected 0-ms image was subtracted from the dark-corrected
nominal image. The difference image was then divided by the
flat- field image corresponding to the filter through which the
image was taken. To convert from these units of 'corrected DN' to
to radiance, the image was divided by its exposure time, a
calibration coefficient (which converts from DNs/time to radiance)
for that filter, and the temperature dependence of the calibration
coefficient as described in MSICAL.TXT.
 
CRDDBL: Cleaned, deblurred radiance images. Images in this directory
have been calibrated to units of radiance beginning with the
procedure described for cleaned radiance images (CRD). In addition,
images were 'deblurred' by application of a Fourier filtering
restoration of a degraded image point-spread function, as described
in MSICAL.TXT.
 
IOF: I/F images. Images in this directory have been calibrated to
units of I/F beginning with the procedure described for radiance
images (RAD). The images were subsequently divided by pi times the
solar irradiance expected at the target body's distance from the Sun.
 
IOFDBL: Deblurred I/F images. Images in this directory have been
calibrated to units of I/F beginning with the procedure described
for I/F images (IOF). In addition, images were 'deblurred' by
application of a Fourier filtering resotration of a degreded image
point-spread funcition, as described in MSICAL.TXT
 
CIF: Cleaned I/F images. Images in this directory have been
calibrated to units of I/F beginning with the procedure described
for cleaned radiance images (CRD). The images were subsequently
divided by pi times the solar irradiance expected at the target
body's distance from the Sun.
 
CIFDBL: Cleaned, deblurred I/F images. Images in this directory
have been calibrated to units of radiance beginning with the
procedure described for cleaned I/F images (CIF). In addition,
images were 'deblurred' by application of a Fourier filtering
restoration of a degraded image point-spread function, as described
in MSICAL.TXT.
 
------------------------------------------------------
 
Parameters
==========
The definitions for the image parameters and other keywords are given
in the file MSIDEFINITIONS.TXT contained in the DOCUMENT/INSTRUMENT
subdirectory.
 
Data
====
The data are in the form of FITS files with attached FITS
headers and detached PDS labels. Data files contain one image
per file.
 
Ancillary Data
==============
Geometry and CALIB subdirectories are described above.
 
Media/Format
============
This data set is released as a CDROM set.
 
Processing History
==================
The processing history includes no background, noise, geometry
or other corrections.

Data Quality Flag
=================
Each data file label includes a quality flag string in the
data_qualITY_ID keyword, extracted from the FITS keyword near-008 of
the original data label. The fields of this keyword are defined below.
Data quality defects flag is raised when there is missing data other
fields informational and not quality related. The eight characters of
this field are described below.
 
Definition - Data Quality Index
 
    c0 = Data Quality Flag (0=good,1=flagged for quality
         defects)
 
    c1 = Instrument Number for FC, CTP and AIU (1 or 2)
 
    c2 - c6 = Processing Flags not quality related
 
    c7 = CCDS Source (0=VC0, 1=VC1, 2=VC2, 3=VC3)
 
 
Review
======
This data set was currently undergoing external peer review within
PDS in July, 2001.