Voyager PPS AAREADME.TXT

Return to PPS data set page.
PDS_VERSION_ID                  = PDS3
RECORD_TYPE                     = STREAM

DATA_SET_ID                     = "VG2-SR/UR/NR-PPS-2/4-OCC-V1.0"

OBJECT                          = TEXT
  PUBLICATION_DATE              = 2003-09-30
  NOTE                          = "General overview of the Voyager 2
PPS ring occultation data set."
END_OBJECT                      = TEXT
END

                VOYAGER 2 PPS RING OCCULTATION ARCHIVE
                --------------------------------------

1. INTRODUCTION

This volume contains the data from the four Voyager 2 Photopolarimeter
(PPS) ring occultation experiments: delta Sco at Saturn, sigma Sgr at
Uranus, beta Per at Uranus, and sigma Sgr at Neptune. The data from
each experiment is provided in a variety of formats ranging from raw
to calibrated and resampled. Also provided are ancillary files
containing geometry, calibration models, and trajectory data, plus
software tools for manipulating the data.

For more detailed information and guidance about how to work with this
data set, see the file DOCUMENT/TUTORIAL.TXT. Most users will find the
calibrated, uniformly-sampled ring profiles in the EASYDATA directory
tree sufficient for their needs. Users wishing to dig further into the
details of the PPS experiment will probably need only consult the
EDITDATA, GEOMETRY and CALIB directories. Most other files in this
archive are provided primarily for documentation purposes and for
users with very special needs.

This data set represents the first component of a data set collection
which will also include the Voyager Ultraviolet Spectrometer (UVS) and
Radio Science (RSS) ring occultation data sets.

Supporting documentation and label files conform to the Planetary Data
System (PDS) Standards, Version 3.5, Jet Propulsion Laboratory (JPL)
document JPL D-7669 (October 15, 2002).

2. VOLUME FORMAT

This disk has been formatted according to the ISO 9660 Level 1
Interchange Standard. This format is compatible with a large variety
of computer systems (e.g. Sun, DEC, Macintosh, PC). For further
information, refer to the ISO 9660 Standard Document, RF# ISO
9660-1988, 15 April 1988.

3. FILE FORMATS

3.1 FILE EXTENSIONS

Files on this volume are named according to PDS standards, where the
1-3 characters after the period indicate the file type. The file types
used on this volume are:

Binary files:
    Images                                      *.IMG, *.GIF
    Other binary data files                     *.DAT
    SPICE ephemeris files                       *.BSP
    Source data files (for documentation only)  *.FOT, *.GS3, *.SCO,
                                                *.SGR,
    Postscript documentation files              *.PS, *.EPS
    Adobe Acrobat documentation files           *.PDF

ASCII text files:
    PDS labels                                  *.LBL
    ASCII tables and indices                    *.TAB
    PDS catalog files                           *.CAT
    Text documentation files                    *.TXT, *.ASC
    TeX documentation files                     *.TEX
    Source code files                           *.C, *.H, *.FOR,
                                                *.INC, *.PRO, *.F1,
                                                *.C1, *.H1
    Software build scripts                      *.COM, *.MAK, *.DEF
    SPICE kernels                               *.TLS, *.TPC
    SPICE transfer ephemeris files              *.XSP
    Pointing files (for documentation only)     *.POI
    Source data files (for documentation only)  *.LIS
    Other files (for documentation only)        *.FDS, *.LOG, *.OUT

3.2 PDS LABELS

Every file in this data set is described by an associated PDS label.
Most files are described by a detached label, which has the same name
as the corresponding file but an extension ".LBL". Text files (*.TXT,
*.CAT) have attached labels.

In some cases, all or most of the files in a given directory share a
single, abbreviated "combined-detached" label. In this case, the name
of the file is the name of the enclosing directory, with extension
".LBL".

See the PDS Standards Reference (JPL D-7669) for a complete
description of the PDS label format. This document can also be found
online at
        //pds.jpl.nasa.gov/stdref/

3.3 ASCII TEXT FILES

Different popular operating systems use different standards for how
ASCII text files are formatted. On Unix systems, lines are terminated
by a <LF> (linefeed character, control-J, ASCII 10). On Macintosh
computers, lines are terminated by a <CR> (carriage return character,
control-M, ASCII 13). On PCs, lines are terminated by a <CR><LF> pair.
PDS standards require all text files to use <CR><LF> line termination.
If the PDS label indicates INTERCHANGE_FORMAT = ASCII or RECORD_TYPE =
STREAM, then this line termination is in use.

On occasion, users on Unix and Macintosh computers may need to change
the line termination on some text files before they can use them. This
can be handled via text editors or a variety of utilities. For
example, the Unix tr (translate) command can be used to change
carriage returns to blanks:
    tr "\015" " " <oldfile.txt >newfile.txt

Some ASCII tables indicate RECORD_TYPE = FIXED_LENGTH and include an
additional parameter RECORD_BYTES, which indicates the length in bytes
of each record in the file. It should be noted that all ASCII files
still include the <CR><LF> line terminators, and these two bytes are
included in the byte count. For this reason, it is unwise to convert
the line terminator to a single character (<LF> on Unix or <CR> on
Macintosh) because this can change the number of bytes per record and
invalidate the label. In these situations, it is recommended that the
line terminator be replaced by a space plus <LF> or a space plus <CR>
instead.

3.4 BINARY FORMATS

The binary data files provided on this volume are tables and images.
As described in the labels, most binary files consist of one- and
two-byte integers. For two-byte integers, the least significant byte
appears first, followed by the most significant byte with (optional)
sign. Users of PCs and Digital workstations will find that these files
are in the native machine format. For users of Macintoshes and
workstations from Sun and Silicon Graphics, binary numbers read from
these files will need to be byte-swapped first. However, note that the
software tools included in the SOFTWARE/PROFILE subdirectory take care
of this conversion automatically.

Some binary files in the SORCDATA and FOVMAPS subdirectories contain
four-byte (single precision) floating-point numbers in Vax format.
This is indicated in the label by DATA_TYPE = VAX_REAL or SAMPLE_TYPE
= VAX_REAL. These are unsupported source data files as provided by
the original investigators; the same data can be found in integer form
in the RAWDATA and EDITDATA subdirectories. However, if a user wishes
to interpret these files, the Vax binary data format (and also every
other binary format supported by the PDS) is documented in complete
detail in Appendix C of the PDS Standards Reference (JPL D-7669, Part
2), which is available online at
        //pds.jpl.nasa.gov/stdref/

The SPICE subdirectory contains ephemeris files for Voyager 2 and
planets and satellites, plus the Sun, Earth, and Moon. These files are
provided in SPICE format for a variety of platforms. For more
information about SPICE data and toolkits, consult the PDS Navigation
and Ancillary Information (NAIF) Node at
        //pds.jpl.nasa.gov/naif.html

4. VOLUME CONTENTS

4.1 FILE NAMING CONVENTIONS

ISO-9660 Level 1 standards require that file names be a maximum of
eight characters. Most of the supported data files provided on this
volume are based on the following nomenclature:

Characters 1-3: Experiment indicator
    1st character: P for PPS.
    2nd character: S for Saturn; U for Uranus; N for Neptune.
    3rd character: 1-8, indicating a stellar occultation sequence
                   number at the given planet.

    Based on these rules, the following indicators have been used:
    PS1   = Saturn delta Sco ring occultation data.
    PS2   = Extended Saturn delta Sco occultation data.
    PS3-8 = Star calibration observations (no rings).
    PU1   = Uranus sigma Sgr ring occultation data.
    PU2   = Uranus beta Per ring occultation data.
    PU3-6 = Star calibration observations associated with Uranus (no
            rings).
    PN1   = Neptune sigma Sgr ring occultation data.

Character 4: File type
    C = calibration models.
    D = edited data.
    G = geometry files.
    J = jitter (instrument pointing) files.
    N = noise data.
    P = resampled, calibrated profiles.
    R = raw data.
    T = trajectory files.
    V = vector files.

Characters 5-6: Version number
    A two-digit number indicating the version number of the given file
    (using a leading zero if necessary). In general, the meaning of
    this number depends on the experiment and file type.

    Note that the vector files are exceptional in that the fifth
    character specifies the coordinate system for the vectors. This
    leaves only the sixth digit to use as a version number.

Characters 7-8: Supplemental
    These characters are only used when needed to further identify a
    file. They are used to distinguish rings, ingress vs. egress,
    coordinate frames, etc. These characters are explained in the
    *INFO.TXT file in each relevant subdirectory.

These naming rules apply to the files in the CALIB, EASYDATA,
EDITDATA, GEOMETRY, JITTER, NOISDATA, RAWDATA, TRAJECT and VECTORS
directories. Non-data files (in the CATALOG, DOCUMENT, INDEX and
SOFTWARE directories) do not follow these conventions. Also, some
ancillary files (FOVMAPS, IMAGES, and SPICE) do not. Finally, the
source data files provided by other investigators (SORCDATA directory)
have been archived under their original names wherever possible.

4.2 DIRECTORY STRUCTURE

The PPS data set is organized in a directory tree as follows:

FILE                    CONTENTS

(root)                  Root directory for this PDS Volume.
|
|-AAREADME.TXT          This file.
|
|-ERRATA.TXT            A file describing any known errors or
|                       deviations from PDS standards.
|
|-VOLDESC.CAT           A PDS volume object, providing a high-level
|                       description of the volume and its contents.
|
|-CALIB/                A directory containing calibration models for
| |                     the ring occultations, in simple ASCII format.
| |
| |-CALINFO.TXT         Description of the files in this directory.
| |
| |-PxxCnn*.TAB         ASCII data files that tabulate models for the
| |                     stellar and background photon counts as a
| |                     function of PPS record index during the given
| |                     occultation.
| |-PxxCnn*.LBL         Detached PDS labels for the above.
|
|-CATALOG/              A directory containing PDS catalog
| |                     information, providing high-level descriptions
| |                     of the data, instruments, etc.
| |
| |-CATINFO.TXT         Description of the files in this directory.
| |
| |-*.CAT               PDS catalog files describing this data set.
|
|-DOCUMENT/             A directory containing useful documentation
| |                     relating to the data on this volume.
| |
| |-DOCINFO.TXT         Description of the files in this directory.
| |
| |-BN1995*.*           Files containing the instrument pointing
| |                     report [BLACK&NICHOLSON1995] in various
| |                     formats.
| |
| |-BN1995/             A subdirectory containing additional files
| |                     associated with [BLACK&NICHOLSON1995].
| |
| |-C1987*.*            Files containing the PPS calibration reports
| |                     [COLEMAN1987A], [COLEMAN1987B], and
| |                     [COLEMAN1987C].
| |
| |-C1988.*             Files containing the PPS calibration report
| |                     [COLEMAN1988].
| |
| |-GRAP2002.TXT        Supplemental information about calibration and
| |                     jitter provided by Amara Graps, MPI fuer
| |                     Kernphysik, August 2002.
| |
| |-PDSDD.TXT           Excerpts from the PDS Data Dictionary,
| |                     defining the keywords appearing in the PDS
| |                     labels of this data set.
| |
| |-POLES.TXT           A memo defining the conversion between ring
| |                     longitudes in B1950 and J2000 coordinates.
| |
| |-TUTORIAL.TXT        A tutorial describing how to use this data
| |                     set and providing background information.
| |
| |-CALIB/              Subdirectories containing programs and
| |-EDITDATA/           intermediate data files documenting the
| |-FOVMAPS/            generation of files in the corresponding
| |-GEOMETRY/           root-level directories. These files are often
| |-JITTER/             referred to in the *INFO.TXT files and in the
| |-RAWDATA/            DESCRIPTION fields of individual labels.
| |-SORCDATA/
| |-TRAJECT/
| |-VECTORS/
|
|-EASYDATA/             A directory containing calibrated, resampled
| |                     ASCII profiles of the rings in a form
| |                     particularly easy to use.
| |
| |-DATAINFO.TXT        A description of the files in the
| |                     subdirectories of this directory.
| |
| |-KM000_1/PxxP01*.TAB Ring profiles at 0.1 km resolution.
| |-KM000_2/PxxP01*.TAB Ring profiles at 0.2 km resolution.
| |-KM000_5/PxxP01*.TAB Ring profiles at 0.5 km resolution.
| |-KM001/PxxP01*.TAB   Ring profiles at 1 km resolution.
| |-KM002/PxxP01*.TAB   Ring profiles at 2 km resolution.
| |-KM005/PxxP01*.TAB   Ring profiles at 5 km resolution.
| |-KM010/PxxP01*.TAB   Ring profiles at 10 km resolution.
| |-KM020/PxxP01*.TAB   Ring profiles at 20 km resolution.
| |-KM050/PxxP01*.TAB   Ring profiles at 50 km resolution.
| |-KM*/PxxP01*.LBL     Detached PDS labels for each of the above.
|
|-EDITDATA/             A directory containing edited data files.
| |                     These have been carefully cleaned and
| |                     reformatted and should be the easiest binary
| |                     files to use.
| |
| |-DATAINFO.TXT        A description of the files in this directory.
| |
| |-PxxDnn*.DAT         Edited data files.
| |-PxxDnn*.LBL         Detached PDS labels for the above.
|
|-FOVMAPS/              A directory containing the PPS 1-degree field
| |                     of view map in various formats.
| |
| |-DATAINFO.TXT        A description of the files in this directory.
| |
| |-FOVMAP.GIF          The PPS field of view map in GIF format.
| |-FOVMAP.LBL          A detached PDS label for the above.
| |
| |-FOVMAPnn.DAT        The PPS field of view map as a simple binary
| |                     file in Vax real, IEEE real, and integer
| |                     formats.
| |-FOVMAP.LBL          Detached PDS labels for the above.
|
|-GEOMETRY/             A directory containing footprint geometry
| |                     models for the ring occultations, in simple
| |                     ASCII format.
| |
| |-GEOMINFO.TXT        Description of the files in this directory.
| |
| |-PxxGnn*.TAB         ASCII data files that tabulate models for the
| |                     ring intercept geometry as a function of PPS
| |                     record index during the given occultation.
| |-PxxGnn*.LBL         Detached PDS labels for the above.
|
|-IMAGES/               A directory containing support images obtained
| |                     during each of the Voyager occultations.
| |
| |-DATAINFO.TXT        Description of the images in this directory.
| |
| |-C1138nnn.IMG        VICAR format images supporting the Neptune
| |                     sigma Sgr occultation. The 7-digit number is
| |                     the associated FDS count.
| |-C2683058.IMG        VICAR format image supporting the Uranus sigma
| |                     Sgr occultation.
| |-C2684902.IMG        VICAR format image supporting the Uranus beta
| |                     Per occultation.
| |-C4400349.IMG        VICAR format image supporting the Saturn delta
| |                     Sco occultation.
| |-*.LBL               Detached PDS labels for each of the above.
|
|-INDEX/                A directory containing indices of the files in
| |                     this data set.
| |
| |-INDXINFO.TXT        Description of the files in this directory.
| |
| |-INDEX.TAB           A table of all the data files on this volume.
| |-INDEX.LBL           A detached PDS label for the above, defining
|                       each column in the table.
|
|-JITTER/               A directory containing jitter (instrument
| |                     pointing) models during the occultations.
| |
| |-DATAINFO.TXT        Description of the files in this directory.
| |
| |-PxxJnn*.TAB         ASCII data files that tabulate models for the
| |                     instrument pointing as a function of PPS
| |                     record index during the given occultation.
| |-PxxJnn*.LBL         Detached PDS labels for the above.
|
|-NOISDATA/             A directory containing edited data files in
| |                     which all ring signal has been removed,
| |                     leaving only noise. These files were used for
| |                     some calibration solutions.
| |
| |-DATAINFO.TXT        A description of the files in this directory.
| |
| |-PxxNnn*.DAT         Edited noise data files.
| |-PxxNnn*.LBL         Detached PDS labels for the above.
|
|-RAWDATA/              A directory containing raw data files. These
| |                     files contain the same values as found in the
| |                     SORCDATA directories but have been
| |                     re-formatted for ease of use.
| |
| |-DATAINFO.TXT        A description of the files in this directory.
| |
| |-PxxRnn*.DAT         Raw data files.
| |-PxxNnn*.LBL         Detached PDS labels for the above.
|
|-SOFTWARE/             A directory containing software libraries to
| |                     support the processing and analysis of the PPS
| |                     data set.
| |
| |-SOFTINFO.TXT        Description of the files in the subdirectories
| |                     of this directory.
| |
| |-OAL/                A subdirectory containing the source code and
| |                     documentation for version 1.3 of the PDS
| |                     Object Access Library and version 1.2 of the
| |                     PDS Light Label Library.
| |
| |-PROFILE/            A subdirectory containing the source code and
|                       documentation for version 1.1 of the Rings
|                       Node's Profile Library.
|
|-SORCDATA/             A directory containing "source" data files as
|                       originally provided to the Ring-Moon Systems Node. These
|                       files are included for documentation purposes
|                       only and are not otherwise supported. See the
|                       RAWDATA directory for supported files.
|
|-SPICE/                A directory containing SPICE ephemeris files
| |                     for the Voyager 2 encounters with Saturn,
| |                     Uranus and Neptune.
| |
| |-DATAINFO.TXT        Description of the files in this directory
| |                     tree.
| |
| |-NAIF0007.TLS        The latest leap seconds file for the SPICE
| |                     toolkit.
| |-NAIF0007.LBL        A detached PDS label for the above.
| |
| |-PCK00006.TPC        The latest body constants file for the SPICE
| |                     toolkit.
| |-PCK00006.LBL        A detached PDS label for the above.
| |
| |-IEEE/               A subdirectory containing binary ephemeris
| | |                   files in SPICE format for machines that use
| | |                   IEEE floating-point format (e.g. Sun, Silicon
| | |                   Graphics, Macintosh).
| | |
| | |-VG2_SAT.BSP       Ephemeris for the Voyager 2 Saturn encounter.
| | |-VG2_SAT.LBL       A detached PDS label for the above.
| | |
| | |-VG2_URA.BSP       Ephemeris for the Voyager 2 Uranus encounter.
| | |-VG2_URA.LBL       A detached PDS label for the above.
| | |
| | |-VG2_NEP.BSP       Ephemeris for the Voyager 2 Neptune encounter.
| | |-VG2_NEP.LBL       A detached PDS label for the above.
| |
| |-PC/                 A subdirectory containing files identical to
| |                     those in the IEEE subdirectory, except in PC
| |                     binary (i.e. byte-swapped IEEE) format. This
| |                     is also the correct format for DEC Alpha
| |                     workstations running Unix.
| |
| |-VAXG/               A subdirectory containing files identical to
| |                     those in the IEEE subdirectory, except in VAXG
| |                     binary format, appropriate for DEC Alpha
| |                     workstations running VMS.
| |
| |-TRANSFER/           A subdirectory containing the same ephemeris
|                       files as the IEEE subdirectory, except in the
|                       SPICE "transfer" (.XSP) ASCII format. These
|                       can be translated to binary for any platform
|                       on which the SPICE toolkit has been
|                       implemented.
|
|-TRAJECT/              A directory containing trajectory models for
| |                     Voyager during the ring occultations.
| |
| |-DATAINFO.TXT        Description of the files in this directory.
| |
| |-PxxTnn*.TAB         ASCII data files that tabulate the trajectory
| |                     of Voyager as a function of PPS record index
| |                     during the given occultation.
| |-PxxTnn*.LBL         Detached PDS labels for the above.
|
|-VECTORS/              A directory containing vector position tables
  |                     from which additional geometry parameters can
  |                     be derived.
  |
  |-DATAINFO.TXT        Description of the files in this directory.
  |
  |-B1950/              A subdirectory containing vector tables based
  | |                   on the B1950 coordinate frame.
  | |
  | |-PxxVCn*.TAB       Vectors in B1950 celestial coordinates.
  | |
  | |-PxxVEn*.TAB       Vectors in planet equator coordinates, where
  | |                   the Z-axis points along the planet's pole.
  | |                   The longitude reference is Earth's B1950
  | |                   equator.
  | |
  | |-PUxVRn*.TAB       Vectors in ring plane coordinates, where the
  | |                   Z-axis points normal to the ring plane. The
  | |                   longitude reference is Earth's B1950 equator.
  | |                   Provided for Uranus only.
  |
  |-J2000/*.TAB         A subdirectory containing vector tables based
  |                     on the J2000 coordinate frame. File names are
  |                     identical to those found in the B1950
  |                     subdirectory.
  |
  |-RINGANOM/           A subdirectory containing vector tables in
    |                   ring anomaly coordinates.
    |
    |-PUxVAn*.TAB       Vectors in ring anomaly coordinates, where the
                        Z-axis points normal to the ring plane and the
                        longitude reference is the ring's pericenter.
                        Provided for Uranus only.

5. CONTACT INFORMATION

PDS Ring-Moon Systems Node personnel:

    Mark Showalter
    SETI Institute
    515 N. Whisman Road
    Mountain View, CA 94043
    650-810-0234
    mshowalter@seti.org

or

    Mitch Gordon
    SETI Institute
    515 N. Whisman Road
    Mountain View, CA 94043
    276-523-0341
    mgordon@seti.org

or

    Neil Heather
    SETI Institute
    515 N. Whisman Road
    Mountain View, CA 94043
    650-810-0243
    nheather@seti.org

    /

For software, data, and further information regarding SPICE data,
contact the PDS Navigation and Ancillary Information Node:

    Charles Acton
    Jet Propulsion Laboratory
    Mail Stop 301-125L
    4800 Oak Grove Drive
    Pasadena, CA
    818-354-3869
    charles.h.acton@jpl.nasa.gov

    //pds.jpl.nasa.gov/naif.html

The PPS team members who carried out the observations archived in this
data set, as of 1986, area as follows. (Note that we have provided
up-to-date contact information where if was available):

    Arthur L. Lane
    Jet Propulsion Laboratory
    Mail Stop 306-473
    4800 Oak Grove Dr.
    Pasadena, CA 91109

    Bonnie J. Buratti
    Jet Propulsion Laboratory
    Mail Stop 183-501
    4800 Oak Grove Dr.
    Pasadena, CA 91109

    Larry W. Esposito
    University of Colorado
    LASP
    Campus Box 392
    Boulder, CO 80309

    Amara L. Graps
    Max Planck Institut fuer Kernphysik
    Saupfercheckweg 1
    Heidelberg, D-69117
    GERMANY

    Charles W. Hord
    University of Colorado
    LASP
    Campus Box 475
    Boulder, CO 80309

    Robert M. Nelson
    Jet Propulsion Laboratory
    Mail Stop 183-501
    4800 Oak Grove Dr.
    Pasadena, CA 91109

    Wayne R. Pryor
    University of Colorado
    LASP
    1234 Innovation Drive
    Boulder, CO 80309

    Karen E. Simmons
    University of Colorado
    1234 Innovation Drive
    Boulder, CO 80309

    Linda J. Spilker
    Jet Propulsion Laboratory
    Mail Stop 183-501
    4800 Oak Grove Dr.
    Pasadena, CA 91109

    Brad D. Wallis
    Jet Propulsion Laboratory
    Mail Stop 300-233
    4800 Oak Grove Dr.
    Pasadena, CA 91109

    Robert A. West
    Jet Propulsion Laboratory
    Mail Stop 169-237
    4800 Oak Grove Dr.
    Pasadena, CA 91109

======================================================================
ACKNOWLEDGMENTS
======================================================================

We thank Joshua Colwell, Amara Graps, Jay Holberg, Philip Nicholson,
Karen Simmons and Linda Spilker for their extensive help in locating
the data files and documents archived herein.

Joshua Colwell, Amara Graps, Ron Joyner, and Richard Simpson provided
extensive, helpful comments as part of the peer review.

Additional assistance with the archiving was provided by Ken Bollinger
and Peter Mariani during their stints at the PDS Ring-Moon Systems Node.

======================================================================
DISCLAIMER
======================================================================

Although considerable care has gone into making this volume, errors
are both possible and likely. Users of the data are advised to
exercise the same caution as they would when dealing with any other
unknown data set.

Reports of errors or difficulties would be appreciated. Please
contact Mark Showalter, Mitch Gordon, or Neil Heather at the addresses
listed above.

Return to PPS data set page.