Index of /volume/hal_0024
Name Last modified Size Description
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browse/ 10-Feb-1991 09:23 -
calib/ 10-Feb-1991 09:32 -
compress/ 10-Feb-1991 09:37 -
crommeln/ 10-Feb-1991 11:57 -
document/ 10-Feb-1991 14:49 -
ephem/ 10-Feb-1991 14:25 -
index/ 10-Feb-1991 15:46 -
software/ 10-Feb-1991 14:15 -
y1984/ 09-Feb-1991 23:31 -
y1985/ 09-Feb-1991 23:12 -
y1986/ 10-Feb-1991 07:09 -
y1987/ 10-Feb-1991 07:11 -
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aareadme.txt 10-Feb-1991 14:32 9.5K
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voldesc.sfd 11-Feb-1991 02:15 867K
***** File AAREADME.TXT
This compact disc (CD-ROM) contains a revised version of the comet
Giacobini-Zinner (P/G-Z) test archive produced by the International Halley
Watch (IHW) in cooperation with the National Space Science Data Center
(NSSDC). The CD-ROM also contains the comet Crommelin archive produced by the
IHW. This disc (which has the volume id. HAL_0024) is included in the larger
set of discs containing the comet Halley archive. There is a mixture of data
types on this disc that comprises 3739 (ground-based) observation files (or
132 MByte) of P/G-Z and 680 observation files (or 39 MByte) of P/Crommelin.
In addition, there are 25 calibration files for P/G-Z and 15 calibration files
for P/Crommelin included.
The data acquired on P/Crommelin during its 1983-84 apparition were part
of a trial run of the IHW organization. Since this first effort by the IHW
wasn't originally intended for inclusion on a CD-ROM, the more sophisticated
aspects of archiving on CD-ROM (utilized for the P/G-Z and P/Halley archives)
are not included for P/Crommelin, e.g. there are no PDS labels included, the
FITS headers have not been detached from the data record files, the indices
included are more primitive and fewer, etc.
The campaign to gather observations of the 1984-87 apparition of P/G-Z
was begun by the IHW to support the NASA mission that sent the International
Cometary Explorer spacecraft through the comet tail on September 11, 1985.
(The results from most experiments on that mission have been archived by
the NSSDC and are provided together with the spacecraft data acquired about
comet Halley on other volumes in the complete CD-ROM set.)
This file is the only text file that is located in the Root directory.
A listing of the contents of the subdirectories for the CD-ROM follows:
BROWSE - subsampled Large Scale Phenomena browse images (of P/G-Z)
ordered chronologically
CALIB - supplemental data (plus headers)
COMPRESS - compressed images (of P/G-Z; Previous Pixel algorithm),
ordered chronologically
DOCUMENT - supporting text files
EPHEM - ephemeris data for comet
INDEX - delimited tables for locating data
SOFTWARE - supporting source and executable code
One directory for each IHW discipline containing complete FITS files
in chronological order (for P/Crommelin) as well as
associated directories for CALIB, EPHEM, INDEX and
DOCUMENT
Chronological directories with FITS headers, data record files, and
PDS labels ordered by time (for P/G-Z):
* 1984 - year only
* 1985 - year, month, day, or half day (00 or 12 hours
period)
* 1986 - year only
* 1987 - year only
An illustration of the subdirectory structure of this CD-ROM is given in
the file, CDTREE.TXT, located in the DOCUMENT subdirectory. Note that all
explanatory files are ASCII text (.TXT) with <CR><LF> characters at the end of
each line. To show special content some files have been given extensions as
follows:
.APX - Appendix (text) files
.C - C source code
.COM - executable file (MS-DOS)
.EXE - executable file (on this disk, either VAX/VMS or MS-DOS)
.FOR - Fortran source code
.HHH - ASCII version of FITS header file
.IDX - delimited table files
.PRO - IDL procedure file
.TXT - text (documentation and information) files
The use of other file extensions (particularly in the INDEX subdirectory)
is considered to be a common practice for dBASE III files, e.g., DBF and STR.
Other file extensions used to document the data are described by various
text files FITSFORM, HDRFORM, IMAGFORM, LBLFORM, SPECFORM, TABLFORM, and
TEXTFORM. Specialized information about other subdirectories is given in the
files listed below:
BRWZINFO.TXT - discusses the browse files (of P/G-Z) and their
structure
CALINFO.TXT - lists the groups of supplemental files (for P/G-Z)
COMPINFO.TXT - lists the compress files
CR_CALIB.TXT - lists the groups of supplemental files (for
P/Crommelin)
CR_EPHEM.TXT - explanation of the ephemeris for P/Crommelin
CR_INDEX.TXT - description of how to use the table data (for
P/Crommelin)
EPHEM.TXT - explanation of the epehemeris for P/G-Z
INDXINFO.TXT - description of how to use the table data (for
P/G-Z)
SOFTINFO.TXT - listing of the software information supplied
There are two special text files in the DOCUMENT directory that give an
overview of the P/G-Z archive (GZGUIDE.TXT) and the P/Crommelin archive
(CROMGUID.TXT), respectively. In addition, the file CDSTRUCT.TXT is a
listing of every file on the disc. It has been used to construct an
inventory file in the root directory (VOLDESC.SFD) following guidelines
of the Consultative Committe on Space Data Systems for machine access.
For more information about the use, content, or structure of the CD-ROM,
please contact one of the following:
M. Aronsson E. Grayzeck, Jr. A. Warnock III
IHW Lead Center Small Bodies Node IHW Large Scale
Planetary Data System Phenomena Network (LSPN)
Mail Stop 169-237 Astronomy Program ST Systems Corp.
NASA/JPL University of Maryland Code 681
4800 Oak Grove Dr. College Park, MD 20742 NASA/Goddard SFC
Pasadena, CA 91109 Greenbelt, MD 20771
SPAN: JPLSC8::MIK SPAN: CHAMP::GRAYZECK SPAN: CHAMP::WARNOCK
or Internet: or Internet: or Internet
MIK@SCN6.JPL.NASA.GOV GRAYZECK@ASTRO.UMD.EDU WARNOCK@STARS.GSFC.NASA.GOV