Index of /volume/hal_0014
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browse/ 02-Jul-1990 17:46 -
c86apr12/ 02-Jul-1990 18:27 -
calib/ 02-Jul-1990 17:54 -
document/ 01-Jul-1990 21:38 -
ephem/ 01-Jul-1990 21:37 -
index/ 01-Jul-1990 21:38 -
software/ 01-Jul-1990 21:37 -
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aareadme.txt 01-Jul-1990 05:45 7.3K
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voldesc.sfd 01-Jul-1990 05:45 23K
***** File AAREADME.TXT
This compact disc (CD-ROM) contains wide-field images of Halley's Comet
obtained by the Large-Scale Phenomena Network (LSPN) of the International
Halley Watch (IHW). The data have been collected, archived, processed, and
prepared for deposit on CD-ROM by the Large-Scale Phenomena (L-SP) Discipline
Specialist Team at the NASA/Goddard Space Flight Center, in cooperation
with the IHW Lead Center at the Jet Propulsion Laboratory and the National
Space Science Data Center (NSSDC) at NASA/GSFC. This disc is one in a series
of compressed image discs dedicated to IHW/L-SP imagery, the series itself
being a subset of the total IHW CD-ROM archive of 30,000 ground-based
observations of Comet Halley. Chronological data from the IHW Disciplines
reside together on a shorter series of multi-discipline CD-ROMs. The IHW
began operations, with NASA funding, in 1982.
A total of 1,439 digital images of Comet Halley are stored on a series of
L-SP compressed data CD-ROMs, as well as 173 images of various calibration
objects. This specific disc contains 58 images of Halley's Comet spanning
the time period 1986 April 12 to Apr 15, and 3 calibration images associated
with a subset of the Halley data. The total volume of data on this CD-ROM
is 620 Mbytes.
This file is the only text file that is in the root directory. A listing
of the contents of the subdirectories for the CD-ROM follows:
BROWSE - subsampled browse images (extension = .IBG), with FITS
headers (.HDR) and PDS labels (.LBL)
C86APR12 - Halley image data, compressed (.IMQ), with FITS headers and
PDS labels
CALIB - calibration data, compressed (.IMQ), with FITS headers and
PDS labels
DOCUMENT - supporting text files
EPHEM - ephemeris data for the comet
INDEX - delimited index tables to aid in locating data
SOFTWARE - supporting source and executable code
An illustration of the subdirectory structure of this CD-ROM is given in
the file CDTREE.TXT, located in the DOCUMENT subdirectory. All .TXT files
are fixed length ASCII text (80 bytes including <CR><LF> characters at the end
of each line). To show specific content, some files have been given
extensions as follows:
.C - C source code
.COM - executable file for MS-DOS
.EXE - executable file (on this disc, either VAX/VMS or MS-DOS)
.FOR - Fortran source code
.IDX - delimited table file
.PRO - Interactive Data Language (IDL) procedure file
The use of other file extensions (particularly in the INDEX subdirectory)
are considered to be a common practice for dBASE files, e.g., .DBF. Some
specialized information about other subdirectories is given in the explanatory
files below:
BRWZINFO.TXT - description of the browse files and their structure
CALINFO.TXT - description of the calibration data files
COMPINFO.TXT - explanation of the compressed image data files
INDXINFO.TXT - description of how to use the table data
SOFTINFO.TXT - listing of the software information supplied
There are two special text files in the DOCUMENT directory that give an
overview to the entire volume: IMAGUIDE.TXT and CDSTRUCT.TXT. The latter
has been used to construct the file VOLDESC.SFD located in the root directory.
This file contains general information similar to what you are reading now
but formulated according to guidelines put forward by the Consultative
Committee on Space Data Systems (CCSDS) for easier access by computers.
M. Aronsson E. Grayzeck, Jr. D. Klinglesmith III
IHW Software Specialist National Space Science IHW Team Member for
for the Lead Center Data Center Large-Scale Phenomena
Jet Propulsion Interferometrics, Inc Laboratory for Astronomy
Laboratory and Solar Physics
Mail Stop 169-237 Code 633 Code 684.0
4800 Oak Grove Dr. NASA/GSFC NASA/GSFC
Pasadena, CA Greenbelt, MD Greenbelt, MD
91109 20771 20771
M. Niedner, Jr. A. Warnock III
IHW Discipline Specialist for IHW Team Member for
Large-Scale Phenomena Large-Scale Phenomena
Laboratory for Astronomy ST Systems Corp
and Solar Physics
Code 684.1 Code 681
NASA/GSFC NASA/GSFC
Greenbelt, MD Greenbelt, MD
20771 20771