PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM DATA_SET_ID = "VG1/VG2-J-ISS-2/3/4/6-PROCESSED-V1.0" OBJECT = TEXT PUBLICATION_DATE = 2013-10-25 NOTE = "General overview of the calibrated Voyager image data set from the Jupiter encounters." END_OBJECT = TEXT END CALIBRATED VOYAGER IMAGES FROM THE JUPITER ENCOUNTERS ---------------------------------------------------- 1. INTRODUCTION This data set contains raw, calibrated and geometrically corrected versions of all the Voyager images from the Jupiter encounters. It has been derived from the compressed raw images that were archived previously by the PDS. Images have been processed following standardized procedures using the VICAR software, as provided by the Multi-mission Image Processing Laboratory at JPL. For more information about the processing procedures, see the file DOCUMENT/PROCESSING.TXT. For details on how to use the images, see DOCUMENT/TUTORIAL.TXT. This data set is far easier to use than the raw, compressed files and is recommended for essentially all scientific purposes. Scientific users should however, heed the comments about calibration accuracy as found in the TUTORIAL.TXT document mentioned above. Intermediate steps in the processing are included for any users who might wish to re-calibrate the data themselves. If you reference this data set in a publication, please cite the work of the PDS Rings Node, as follows: Showalter, M.R., M.K. Gordon, and D. Olson, VG1/VG2 JUPITER ISS PROCESSED IMAGES V1.0, VGISS_5101-5214, NASA Planetary Data System, 2013. It would also be appropriate to acknowledge the work of the Voyager imaging team, as led by Dr. Brad Smith. For example see these two papers: Smith, B.A., L.A. Soderblom, T.V. Johnson, A. Ingersoll, S.A. Collins, E.M. Shoemaker, G.E. Hunt, H. Masursky, M.H. Carr, M.E. Davies, A.F. Cook II, J. Boyce, G.E. Danielson, T. Owen, C. Sagan, R.F. Beebe, J. Veverka, R.G. Strom, J.F. McCauley, D. Morrison, G.A. Briggs, V.E. Suomi, The Jupiter System Through the Eyes of Voyager 1, Science, 204, 951-972, 1979. [SMITHETAL1979A] Smith, B.A., L.A. Soderblom, R. Beebe, J. Boyce, G. Briggs, M. Carr, S.A. Collins, A.F. Cook II, G.E. Danielson, M.E. Davies, G.E. Hunt, A. Ingersoll, T.V. Johnson, H. Masursky, J. McCauley, D. Morrison, T. Owen, C. Sagan, E.M. Shoemaker, R. Strom, V.E. Suomi, J. Veverka, The Galilean Satellites and Jupiter: Voyager 2 Imaging Science Results, Science, 206, 927-950, 1979. [SMITHETAL1979B] 2. VOLUME FORMAT This is a virtual volume, which is too large to fit on current hard storage media such as DVD-ROM. It is currently only available as a directory tree stored on a hard drive. 3. FILE FORMATS 3.1 FILE EXTENSIONS Files on this volume are named according to PDS standards, where the characters after the period indicate the file type. The file types used on this volume are: ASCII text files: PDS detached labels *.LBL ASCII tables and indices *.TAB PDS catalog files *.CAT Text documentation files *.ASC, *.TXT HTML documents *.HTM Binary files Binary images *.IMG Binary data files *.DAT Browse images *.JPG Graphical images for documents *.GIF Adobe Acrobat documentation files *.PDF 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". Most text files (*.TXT, *.CAT) have attached labels. Some pairs of files have the same name but different extensions, e.g. Cnnnnnnn_RESLOC.TAB and .DAT. These files have combined-detached labels, where a single label file Cnnnnnnn_RESLOC.LBL describes both files. See the PDS Standards Reference (JPL D-7669) for a complete description of the PDS label format. This document can also be found on line at http://pds.nasa.gov/tools/standards-reference.shtml 3.3 ASCII TEXT FILES Different popular operating systems use different standards for how ASCII text files are formatted. On Unix systems and modern Macintosh computers, lines are terminated by a (linefeed character, control-J, ASCII 10). On older Macintosh computers, lines are terminated by a (carriage return character, control-M, ASCII 13). On PCs, lines are terminated by a pair. PDS standards require all text files to use 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" " " 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 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 ( on Unix or on Macintosh) because this can change the number of bytes per record and make it incompatible with the label. In these situations, it is recommended that the line terminator be replaced by a space plus or a space plus instead. 3.4 BINARY FILES The binary files on this volume are provided in VICAR format. This is a relatively simple fixed-length file format consisting of an ASCII header followed by consecutive rows of the image as binary integers. See http://www-mipl.jpl.nasa.gov/external/VICAR_file_fmt.pdf a complete description of the VICAR file format. This information can also be found on this volume in DOCUMENTS/VICAR.ASC and DOCUMENTS/VICAR.HTML. Some binary files contain two-byte integers. All two-byte binary integers are in least-significant-byte (LSB) format. This is the native format for Intel-based computers. For computers from Sun and for Macintosh PowerPC-based computers, users may need to perform a pair-wise swap of the bytes prior to using these data files. Floating-point (REAL) binary numbers are in the native Vax D-floating format. This format is no longer widely used so most of these files have also been converted to ASCII text format for convenience. Browse images are provided in JPG format. 4. VOLUME CONTENTS 4.1 VOLUME NAMES The PDS originally released raw, compressed "EDR" versions of all the Voyager images on a set of CD-ROMs identified VG_0001 through VG_0038. The organization of that series is as follows: VG_0001-0003: The complete Uranus images VG_0004-0005: Selected Saturn images VG_0006-0008: Selected Jupiter images VG_0009-0012: The complete Neptune images VG_0013-0025: The complete Jupiter images VG_0026-0038: The complete Saturn images This derived set of volumes has been derived from VG_0006, VG_0007, VG_0008 and VG_0013-0025. The boundaries between the new volumes are chronological, as defined by Voyager's Flight Data System ("FDS") clock. Within the Jupiter data set, boundaries between volumes are as follows Volume Vgr FDS range VGISS_5101 1 13854.55 -- 14999.59 VGISS_5102 1 15000.00 -- 15199.59 VGISS_5103 1 15200.00 -- 15399.59 VGISS_5104 1 15400.00 -- 15449.59 VGISS_5105 1 15450.00 -- 15499.59 VGISS_5106 1 15500.00 -- 15599.59 VGISS_5107 1 15600.00 -- 15699.59 VGISS_5108 1 15700.00 -- 15799.59 VGISS_5109 1 15800.00 -- 15899.59 VGISS_5110 1 15900.00 -- 15999.59 VGISS_5111 1 16000.00 -- 16099.59 VGISS_5112 1 16100.00 -- 16199.59 VGISS_5113 1 16200.00 -- 16249.59 VGISS_5114 1 16250.00 -- 16299.59 VGISS_5115 1 16300.00 -- 16349.59 VGISS_5116 1 16350.00 -- 16399.59 VGISS_5117 1 16400.00 -- 16449.59 VGISS_5118 1 16450.00 -- 16499.59 VGISS_5119 1 16500.00 -- 16999.59 VGISS_5120 1 17000.00 -- 17574.27 VGISS_5201 2 18110.30 -- 18799.59 VGISS_5202 2 18800.00 -- 19199.59 VGISS_5203 2 19200.00 -- 19399.59 VGISS_5204 2 19400.00 -- 19599.59 VGISS_5205 2 19600.00 -- 19799.59 VGISS_5206 2 19800.00 -- 19999.59 VGISS_5207 2 20000.00 -- 20199.59 VGISS_5208 2 20200.00 -- 20299.59 VGISS_5209 2 20300.00 -- 20399.59 VGISS_5210 2 20400.00 -- 20499.59 VGISS_5211 2 20500.00 -- 20549.59 VGISS_5212 2 20550.00 -- 20599.59 VGISS_5213 2 20600.00 -- 20649.59 VGISS_5214 2 20650.00 -- 20863.06 4.2 FILE NAMING CONVENTIONS All files are named by the associated seven-digit FDS clock count (without a decimal point) at the time the image was read out of the vidicon. For example, a file named C3456712*.* is associated with the image read out at FDS time 34567.12. For most images, this corresponds to the time when an exposure ended; however, in some circumstances (modes "BOTSIM" and "BSIMAN") both the wide-angle and narrow-angle cameras were triggered simultaneously; under these circumstances, the narrow-angle camera was read out first and the wide-angle image has an FDS number a few digits higher. In the original raw, compressed volumes, files were named Cnnnnnnn.IMQ where 'nnnnnnn' is the FDS count and "IMQ" indicates that the file is a compressed image. In this data set, the associated files have the following names: Cnnnnnnn_RAW.IMG: uncompressed, raw image. Cnnnnnnn_RAW.LBL: detached PDS label for the above. Cnnnnnnn_CLEANED.IMG: cleaned version of the image, with spikes and reseau markings erased. Cnnnnnnn_CLEANED.LBL: detached PDS label for the above. Cnnnnnnn_RESLOC.DAT: binary table of reseau marking locations. Cnnnnnnn_RESLOC.TAB: ASCII table of reseau marking locations. Cnnnnnnn_RESLOC.LBL: combined-detached PDS label for both of the above. Cnnnnnnn_CALIB.IMG: calibrated image. Cnnnnnnn_CALIB.LBL: detached PDS label for the above. Included in the label is the rough conversion factor from pixel values to absolute reflectivity. Cnnnnnnn_GEOMA.DAT: binary table of tie points for modeling the geometric distortion. Cnnnnnnn_GEOMA.TAB: ASCII table containing the same information as the above. Cnnnnnnn_GEOMA.LBL: combined-detached PDS label for both of the above. Cnnnnnnn_GEOMED.IMG: geometrically corrected version of the calibrated image. Cnnnnnnn_GEOMED.LBL: detached PDS label for the above. 4.3 DARK CURRENT FILE NAMING CONVENTIONS The CALIB/DARKS subdirectory contains the dark current files generated for the calibration process. They are named as follows: DCa_bb_cc{_BS}_X100.IMG where a = 1 for Voyager 1; 2 for Voyager 2. bb = WA for the wide-angle camera; NA for the narrow-angle camera. cc = 11 for scan rate 1:1 21 for scan rate 2:1 31 for scan rate 3:1 "_BS" appears in the file name for wide-angle images taken in BOTSIM or BSIMAN mode; this text does not appear for other images. "X100" indicates that all dark current images have been scaled by a factor of 100 for enhanced precision. For further details about these images, see DOCUMENTS/PROCESSING.TXT. 4.4 DIRECTORY STRUCTURE The directory structure matches that of the original Voyager image volumes. 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. | |-BROWSE/ A directory containing full-resolution JPEG previews | | of each image. | | | |-CnnnnnXX/ Subdirectory that divides the the data files, based on | | the first five digits of the spacecraft clock (FDS) | | count. | | | |-Cnnnnnnn_*.JPG JPEG image. | |-Cnnnnnnn_*.LBL A detached PDS label for the above. | |-CALIB/ A directory containing calibration data and support | | files. Only found on volumes VGISS_5120 and | | VGISS_5214 | | | |-CALINFO.TXT A brief description of the subdirectories. | | | |-DARKS/ A subdirectory containing the dark current files used | | | in the calibration of these images. | | | | | |-CALINFO.TXT A brief description of the files in this directory. | | | | | |-DC*.IMG A dark current image in VICAR format. | | |-DC*.LBL A detached label for each of the above. | | | |-MIPL/ A directory containing the support files obtained from | | JPL's Multi-mission Image Processing Laboratory. | | | |-DATAINFO.TXT Description of the files in this directory. | | | |-FICOR77_VGRSCF.DAT File of calibration correction factors. | |-FICOR77_VGRSCF.LBL Detached PDS label for the above. | | | |-FICOR77_VGn_camera_filter.DAT Calibration file for each Voyager | | spacecraft, camera and filter. | |-FICOR77_VGn_camera_filter.LBL Detached PDS label for the above. | | | |-RESSAR77_VGn_camera.DAT Default blemish location files for | | each Voyager spacecraft and camera. | |-RESSAR77_VGn_camera.LBL Detached PDS label 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. | |-DATA/ A directory containing the data files. | | | |-CnnnnnXX/ Subdirectory that divides the the data files, based on | | the first five digits of the spacecraft clock (FDS) | | count. | | | |-Cnnnnnnn_*.IMG Image files named as described above. | |-Cnnnnnnn_*.DAT Binary tables named as described above. | |-Cnnnnnnn_*.TAB ASCII tables named as described above. | |-Cnnnnnnn_*.LBL Detached or combined-detached PDS labels. | |-DOCUMENT/ A directory containing documentation. | | | |-DOCINFO.TXT A description of the files in this directory. | | | |-*.ASC Documentation in ASCII text format. | |-*.HTM Documentation in HTML text format. | |-*.GIF Documentation in the form of images in GIF format. | |-*.TXT Documentation in ASCII text format. | |-*.LBL A detached PDS label for any of the above. | | | |-FILTERS/ A subdirectory containing filter information in HTML | | | and GIF format. | | | | | |-DOCINFO.TXT A description of the files in this directory. | | | | | |-INDEX.HTM The starting point of some HTML pages containing | | | filter and calibration information. | | | | | |-VG*.HTM An HTML page describing a filter. | | |-VG*.GIF If available, a plot of the filter bandpass. | | | | | |-FILTERS.LBL A PDS label for all of the above HTML and GIF files. | | | |-REPORTS/ Calibration reports and memos associated with the | | Voyager cameras. | | | |-DOCINFO.TXT A description of the files in this directory. | | | |-*.ASC Documents in ASCII text format. | |-*.GIF GIF images of associated figures. | |-*.PDF Documents in Adobe Acrobat format. | |-*.LBL A detached PDS label for each of the above. | |-INDEX/ A directory containing an index of all the data files | on this volume. | |-INDXINFO.TXT Description of the files in this directory. | |-INDEX.TAB An index of all the data files on the volume. |-INDEX.LBL A detached PDS label for the above. | |-CUMINDEX.TAB An cumulative index of all the data files in this data | set. |-CUMINDEX.LBL A detached PDS label for the above. 5. METADATA A note about TARGET_NAMEs. Many images contain more than one target. The targets indicated in the label files were nominal targets at the time of observation. Many images missed their intended targets. The values, which are the same as the directory name in the original voyager archive, provides nothing more than general guidance about which images may be of interest. OPUS, the Rings Node's search tool provides a wide range of parameters to use to find images with specific content: http://pds-rings.seti.org/search/ 6. CONTACT INFORMATION Mark Showalter SETI Institute 189 Bernardo Ave Mountain View, CA 94043 650-810-0234 mshowalter@seti.org Mitch Gordon 276-393-8822 mgordon@seti.org http://pds-rings.seti.org/ ============================================================================== ACKNOWLEDGMENTS ============================================================================== We recognize the contribution of Brad Smith and the Voyager Imaging Team for their work in obtaining this extraordinary data set. Mark Showalter acknowledges James Pollack and Jeff Cuzzi for teaching him so many of the ins and outs of Voyager image calibration and processing. We thank JPL's Multimission Instrument Processing Laboratory for writing and maintaining the VICAR software. Gary Yagi of JPL provided updates and helpful advice on several VICAR routines. The PDS Imaging Node provided additional guidance and support. At the Rings Node, Danny Olson provided extensive archiving support. ============================================================================== 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 or Mitch Gordon at the addresses listed above.