SPECTROSCOPY AND SPECTROPHOTOMETRY NETWORK                                                                        
                                                                                                                                  
                                                                                                                                  
This directory contains the digital appendices for  the  Spectroscopic                                                            
and  Spectrophotometry  Network  (SSN)  for  the  International Halley                                                            
Watch.  The files included are described below.                                                                                   
                                                                                                                                  
      o  SP_CODE.* - This is a set of files which contain and describe                                                            
         a table to translate the DIS-CODE keyword into its meaningful                                                            
         parts.  There is a description file (.TXT), a delimited  file                                                            
         (.TAB),  a  table  header  file  (.STR), a FITS header (.FIT,                                                            
         blocked for 2880 bytes), and a "readable" FITS header  (.HHH,                                                            
         blocked for 80 bytes).  This table is intended for entry into                                                            
         a database program for use.                                                                                              
                                                                                                                                  
      o  SP_HISTO.* - This  is a  histogram of  number  of spectra  in                                                            
         archive vs  date.  The data (.DAT) is a two column ASCII file.                                                           
         There is a description file as well (.TXT).                                                                              
                                                                                                                                  
                                                                                                                                  
I. INTRODUCTION                                                                                                                   
                                                                                                                                  
          The 1985 apparition of comet P/Giacobini-Zinner became historical with                                                  
the success of the U.S. International Cometary Explorer (ICE), the first space-                                                   
craft mission to a comet.  On 11 September 1985, six days after perihelion, the                                                   
ICE spacecraft passed through the coma, approaching to within 7800 km of the                                                      
comet's nucleus.  Spectroscopic observations obtained while the ICE spacecraft                                                    
transited the coma are included in the IHW Spectroscopy and Spectrophotometry                                                     
Network (SSN) archive together with good coverage of spectra obtained both                                                        
before and after perihelion.                                                                                                      
                                                                                                                                  
          The personnel of the Discipline Specialist Team of the Spectroscopy                                                     
and Spectrophotometry Network is listed in Table I.  The Center collected 433                                                     
spectra of the comet and associated calibration spectra.  The completed spectro-                                                  
scopic archive includes observations that cover the period from 6 months prior                                                    
to perihelion to 4 months after perihelion, which corresponds to heliocentric                                                     
distances of 2.3 and 1.6 AU, respectively.                                                                                        
                                                                                                                                  
                                                                                                                                  
Table I.  Discipline Specialist Team of the Spectroscopy and Spectrophotometry                                                    
          Network                                                                                                                 
________________________________________________________________________________                                                  
                                                                                                                                  
Team Member          Affiliation                 Responsibility                                                                   
________________________________________________________________________________                                                  
                                                                                                                                  
Susan Wyckoff        Physics Department          Discipline Specialist                                                            
                     Arizona State University                                                                                     
                     Tempe, AZ 85281                                                                                              
                     U.S.A.                                                                                                       
                                                                                                                                  
Peter A. Wehinger    Physics Department          Discipline Specialist                                                            
                     Arizona State University                                                                                     
                                                                                                                                  
Michel Festou        Observatoire de Besancon    Discipline Specialist                                                            
                     F-2544 Besancon Cedex                                                                                        
                     France                                                                                                       
                                                                                                                                  
Beverly Dunlap       Physics Department          Office Manager & Data Assistant                                                  
                     Arizona State University                                                                                     
                                                                                                                                  
Anthony J. Ferro     Physics Department          Scientific Programmer & Data                                                     
                     Arizona State University      Assistant                                                                      
                                                                                                                                  
Gregory Loper        Physics Department          Archivist & Data Cataloguer                                                      
                     Arizona State University                                                                                     
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
          The detectors used to record the spectra in the archive include a                                                       
microchannel plate with output recorded on photographic film, an SEC Vidicon for                                                  
IUE data, a scanning photoelectric scanner, an image dissector scanner, and                                                       
several different charge-coupled devices (CCDs).  The spectrographs were all                                                      
located at the Cassegrain foci of telescopes which ranged in aperture from 2 to                                                   
4 meters, situated in both the northern and southern hemispheres.  Ten percent                                                    
of the archive data were obtained with CCDs and are in two-dimensional format.                                                    
                                                                                                                                  
          The Discipline Specialist Team requested that the spectroscopic obser-                                                  
vations be submitted in FITS format, and both flux and wavelength calibrated.                                                     
Most submitters complied with this request.  The FITS headers identify the                                                        
spectra in the archive that are not in the SSN standard units (ergs cm-2 s-1                                                      
Angstrom-1 for flux, and Angstrom units for wavelength), or are not calibrated.                                                   
                                                                                                                                  
          The archive appears in two forms, printed and digital.  In the printed                                                  
version, the temporal distribution of the observations is presented in Fig. 1.                                                    
In the digital version, this figure can be generated from information in the                                                      
file HISTO.* (cf. Sec. III).                                                                                                      
                                                                                                                                  
                                                                                                                                  
II. THE PRINTED ARCHIVE                                                                                                           
                                                                                                                                  
          The printed archive is a hard-copy volume which contains a one-line                                                     
description of each spectrum extracted from the digital archive (Sec. III).  The                                                  
column headings given for each spectrum in the printed archive are described in                                                   
Table II.                                                                                                                         
                                                                                                                                  
                                                                                                                                  
Table II.  Entries in the Printed Archive                                                                                         
________________________________________________________________________________                                                  
                                                                                                                                  
Heading            Description                                                                                                    
________________________________________________________________________________                                                  
                                                                                                                                  
Date(UT)           Date (day & fraction of day) of middle of observation [UT].                                                    
                     Same as FITS keywords DATE-OBS and TIME-OBS.                                                                 
                                                                                                                                  
SSN#               A running number for each observation, where initial digit 7                                                   
                     identifies the Spectroscopy and Spectrophotometry Network.                                                   
                     Same as FITS keyword FILE-NUM.                                                                               
                                                                                                                                  
Resol              Approximate spectral resolution [Angstrom].  Same as FITS                                                      
                     keyword RESOL-SP.                                                                                            
                                                                                                                                  
Range              Approximate spectral range [Angstrom].  Same as FITS keyword                                                   
                     RANGE-SP.                                                                                                    
                                                                                                                                  
ExpS               Exposure or integration time of observation [s]. Same as FITS                                                  
                     keyword EXPOSURE.                                                                                            
                                                                                                                                  
DiscCode           Discipline specific code.  This is a 9 digit number giving                                                     
                     coded information about the observation.  The detector                                                       
                     number, the instrument number (both assigned by the SSN),                                                    
                     the wavelength region, the approximate spectral resolution                                                   
                     and the quality of the data are encoded as DDCCWWWRQ where:                                                  
                                                                                                                                  
                     DD = detector number                                                                                         
                     CC = instrument configuration number                                                                         
                     WWW = wavelength region included.  A binary coding scheme                                                    
                       has been used to specify a unique number for a wavelength                                                  
                       region.  This number is the sum of all defined values                                                      
                       from the table below for each spectral region present.                                                     
                       The defined values and the corresponding wavelength                                                        
                       regions [A] are:                                                                                           
                                                                                                                                  
                       1 = < 3000                                                                                                 
                       2 = 3000 - 3499                                                                                            
                       4 = 3500 - 3999                                                                                            
                       8 = 4000 - 4999                                                                                            
                       16 = 5000 - 5999                                                                                           
                       32 = 6000 - 6999                                                                                           
                       64 = 7000 - 7999                                                                                           
                       128 = 8000 - 10000                                                                                         
                       256 = > 10000                                                                                              
                                                                                                                                  
                     Example: for 3200-6900 A, WWW = 2+4+8+16+32 = 062.                                                           
                                                                                                                                  
                     R = spectral resolution.  This digit is assigned a value                                                     
                       based on the corresponding spectral resolutions (FWHM in                                                   
                       A) given below:                                                                                            
                                                                                                                                  
                       1 = <= 0.05                                                                                                
                       2 = > 0.05 - 0.2                                                                                           
                       3 = > 0.2 - 1                                                                                              
                       4 = > 1 - 5                                                                                                
                       5 = > 5 - 10                                                                                               
                       6 = > 10 - 20                                                                                              
                       7 = > 20 - 50                                                                                              
                       8 = > 50 - 100                                                                                             
                       9 = > 100                                                                                                  
                                                                                                                                  
                     Q = quality of the data.  A subjective judgement on the                                                      
                       quality of the data is taken from the QUALITY keyword.                                                     
                       The following values are assigned:                                                                         
                                                                                                                                  
                       0 = Unknown                                                                                                
                       1 = Excellent                                                                                              
                       2 = Very Good                                                                                              
                       3 = Good                                                                                                   
                       4 = Fair                                                                                                   
                       5 = Poor                                                                                                   
                                                                                                                                  
Typ                Data type.  Same as FITS keyword DAT-TYPE.  One of the                                                         
                     following:                                                                                                   
                                                                                                                                  
                     U = Unknown                                                                                                  
                     R = Reduced Digital                                                                                          
                     X = Raw Digital                                                                                              
                     P = Photographic                                                                                             
                     O = Objective Prism                                                                                          
                     I = Interferometer                                                                                           
                     S = Space Borne                                                                                              
                                                                                                                                  
Slit               Aperture diameter (for a circular slit) or slit width and                                                      
                     length (for a rectangular slit) given [arcsec].  Same as                                                     
                     FITS keyword APERSIZE.                                                                                       
                                                                                                                                  
PAs                Position angle of slit, measured north through east [deg].                                                     
                     Same as FITS keyword POSANG.                                                                                 
                                                                                                                                  
Airm               Airmass of observation, followed by a character to indicate                                                    
                     whether its value is for beginning (B), middle (M), end                                                      
                     (E), average (A) of observation. Same as FITS keywords                                                       
                     AIRM-BEG, AIRM-MID, AIRM-END, and AIRM-AVE.                                                                  
                                                                                                                                  
N                  Number of axes in data.  Same as FITS keyword NAXIS.                                                           
                                                                                                                                  
n(lambda)          Number of pixels in wavelength direction.  Same as FITS key-                                                   
                     word NAXIS1.                                                                                                 
                                                                                                                                  
n(y)               Number of pixels in spatial direction.  Same as FITS keyword                                                   
                     NAXIS2.                                                                                                      
                                                                                                                                  
C                  Code for type of first independent variable.  Same as FITS                                                     
                     keyword CTYPE1.                                                                                              
                                                                                                                                  
                     1 = Angstrom                                                                                                 
                     2 = Velocity [km/s]                                                                                          
                     3 = Pixel number                                                                                             
                     4 = Projected distance [arcsec]                                                                              
                     5 = Other (described in COMMENT filed in header)                                                             
                                                                                                                                  
B                  Code for type of dependent variable.  Same as FITS keyword                                                     
                     BUNIT.                                                                                                       
                                                                                                                                  
                     1 = Flux per wavelength interval                                                                             
                     2 = Flux per frequency interval                                                                              
                     3 = Flux in Rayleighs per Angstrom unit                                                                      
                     4 = Relative intensity                                                                                       
                     5 = Counts or counts per second                                                                              
                     6 = Density                                                                                                  
                     7 = Other (described in COMMENT field in header)                                                             
                                                                                                                                  
Offset rho         Separation between center of slit or aperture and center of                                                    
                     nucleus [arcsec].                                                                                            
                                                                                                                                  
Offset theta       Orientation of the slit center with respect to the center of                                                   
                     the nucleus, measured from north through east [deg].  Same                                                   
                     as FITS keyword ORIENT.                                                                                      
                                                                                                                                  
System             System station code.  This is an eight digit number.  The                                                      
                     first digit is the IHW network number, followed by the                                                       
                     3-digit IAU observatory number, a 2-digit telescope number                                                   
                     assigned by the Large Scale Phenomena Network, and an                                                        
                     instrument/detector number assigned by the SSN.  Same as                                                     
                     FITS keyword SYSTEM.                                                                                         
                                                                                                                                  
Observer(s)        The main observer(s) during the observation.  Same as FITS                                                     
                     keyword OBSERVER                                                                                             
                                                                                                                                  
Notes              This field indicates if there are any special notes about the                                                  
                     observation.  Same as FITS keyword COMMENT NOTE.                                                             
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
          Representative spectra of comet P/Giacobini-Zinner are also included                                                    
in the printed archive.  The data submitted to the SSN Network were of two basic                                                  
types, one- or two-dimensional spectra.  The one-dimensional spectra are                                                          
presented as plots of flux vs. wavelength.  The two-dimensional spectra are                                                       
presented as gray-scale images in the printed archive.  Approximately 10 percent                                                  
of the SSN data is in form of two-dimensional spectra obtained with long-slit                                                     
spectrographs.                                                                                                                    
                                                                                                                                  
                                                                                                                                  
III. DIGITAL ARCHIVE                                                                                                              
                                                                                                                                  
          The digital archive on the CD-ROM laser disk contains all of the                                                        
spectroscopic data of comet P/Giacobini-Zinner together with related appendices                                                   
and a table.  Each archived spectrum (one- or two-dimensional) consists of a set                                                  
of three files:                                                                                                                   
                                                                                                                                  
1.  A Planetary Data System (PDS) header -- a short header describing the data                                                    
    file, so that PDS software can be used to display the archived data.  Note                                                    
    that only minimal header information is included in this file.                                                                
                                                                                                                                  
2.  Flexible Image Transport System (FITS) header -- a longer header in FITS                                                      
    format (Wells et al. 1981).  The FITS header contains both standard keywords                                                  
    as well as keywords specific to the IHW-SSN. The FITS keywords are described                                                  
    below and in the digital files INTRO.TXT (this writeup) and CODE.*.  The                                                      
    purpose of the FITS header is to describe the data contained in the                                                           
    associated file.  Programs such as the Image Reduction and Analysis Facility                                                  
    (IRAF) developed at the National Optical Astronomy Observatories (NOAO) can                                                   
    be used to display and analyze the FITS formated archive data.                                                                
                                                                                                                                  
3.  Data -- the data in the form of an integer byte stream are in the associated                                                  
    data file.                                                                                                                    
                                                                                                                                  
          To aid users of the digital archive on the CD-ROM disk in examining                                                     
the contents of the SSN data, several descriptive appendices and tables have                                                      
been included in the digital version of the archive.  The appendices include                                                      
statistics on the number of spectra in the archive (HISTO.*), as well as this                                                     
file (INTRO.TXT).  In addition a set of files is included in the digital archive                                                  
(CODE.*), which translates the FITS header keyword DIS-CODE and which presents                                                    
the archive user with files that facilitate the use of data base programs to                                                      
examine the contents of the archive.  The appendices and the de-coding table are                                                  
described in Table III and more fully in the appropriate digital files:                                                           
                                                                                                                                  
                                                                                                                                  
Table III.  Description of Appendices to Digital Archive                                                                          
________________________________________________________________________________                                                  
                                                                                                                                  
File           Contents                                                                                                           
________________________________________________________________________________                                                  
                                                                                                                                  
AAREADME.TXT   General description and table of contents of the digital files                                                     
                 which consist of the SSN appendices, and the DIS-CODE table,                                                     
                 together with its associated files.                                                                              
                                                                                                                                  
INTRO.TXT      Copy of this writeup.                                                                                              
                                                                                                                                  
HISTO.*        Statistical compilation of the number of spectra of P/Giacobini-                                                   
                 Zinner included in the archive and the times of observation.                                                     
                 This file can be used to construct a histogram for the obser-                                                    
                 vational coverage of the SSN.                                                                                    
                                                                                                                                  
CODE.*         Set of files which describe and translate the FITS keyword                                                         
                 DIS-CODE.  The purpose of including this keyword in the header                                                   
                 for each spectrum in the archive is to facilitate data base                                                      
                 program searches of the spectra.  The DIS-CODE keyword is a                                                      
                 9-digit coded integer which contains information about the                                                       
                 instrumentation used to obtain the spectrum, the wavelength                                                      
                 range, aperture size and the spectral resolution, as well as                                                     
                 the quality of the spectrum.  DIS-CODE is described fully                                                        
                 below, and files are given in CODE.* to aid translating                                                          
                 DIS-CODE by entering it into data base programs.  The CODE.TAB                                                   
                 file lists the translations of the DIS-CODE keyword in tabular                                                   
                 form.  The DIS-CODE keyword is defined by information provided                                                   
                 in the FITS header of any spectrum.  The table contained in                                                      
                 CODE.TAB is formatted for ease of use in data base programs                                                      
                 (as a delimited format table).  As an aid for using CODE.TAB                                                     
                 in data base programs, another file is provided, CODE.STR,                                                       
                 which may be used to define a DIS-CODE table format in a data                                                    
                 base program.  The CODE.STR file contains a data base format                                                     
                 that gives the column heading entry type (character, numerical                                                   
                 or date), the column widths and the number of decimal places                                                     
                 for using a data base program to display the table in CODE.TAB.                                                  
                 A header file CODE.FIT for the CODE.TAB file is also supplied,                                                   
                 which when attached to the data in CODE.TAB provides a header                                                    
                 in standard FITS format.  The file CODE.HHH contains the same                                                    
                 data as the CODE.FIT file, but has 80 byte records (as opposed                                                   
                 to 2880 for the CODE.FIT file).  This is to allow easy display                                                   
                 of the file.                                                                                                     
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
IV. DESCRIPTION OF IHW-SSN FITS KEYWORDS                                                                                          
                                                                                                                                  
                                                                                                                                  
          Table IV describes the keywords used in the FITS headers of the SSN                                                     
data.  Each keyword is listed in capital letters, followed by an initial that                                                     
indicates whether the variable is a logical (L), integer (I), floating point                                                      
(F), or character string (C).                                                                                                     
                                                                                                                                  
          For several FITS keywords, there are several forms of the keyword,                                                      
usually relating to various axes.  In these cases, the keyword is listed as                                                       
XXXXn, where n is the number of the axis which the keyword describes.                                                             
                                                                                                                                  
                                                                                                                                  
Table IV.  Keywords in the FITS headers                                                                                           
________________________________________________________________________________                                                  
                                                                                                                                  
Keyword   Type  Description                                                                                                       
________________________________________________________________________________                                                  
                                                                                                                                  
SIMPLE     L    Does the file conform to the FITS format?  If yes, the keyword                                                    
                  is set to T.  Otherwise the keyword is F.  This keyword should                                                  
                  be set to true for all SSN files.                                                                               
                                                                                                                                  
BITPIX     I    Keyword contains the number of bits in each pixel.  This value                                                    
                  is either 16 or 32 for SSN data.                                                                                
                                                                                                                                  
NAXIS      I    Keyword contains the number of axes in the data: 1-dimensional                                                    
                  spectra have a value of 1, 2-dimensional spectra a value of 2.                                                  
                                                                                                                                  
NAXISn     I    n is a number in the range of 1 to NAXIS.  Keyword contains the                                                   
                  length of axis. NAXIS1 is the dimension of the fastest varying                                                  
                  axis in the data.  NAXIS2 is the second fastest varying axis,                                                   
                  etc.                                                                                                            
                                                                                                                                  
EXTEND     L    Does the file contain extensions conforming to the FITS stan-                                                     
                  dards?  For all SSN data files, EXTEND = F (no extensions).                                                     
                                                                                                                                  
                                                                                                                                  
OBJECT     C    Keyword contains the name of the object of the data.                                                              
                                                                                                                                  
FILE-NUM   I    This is a running number of the files sent to the archive.  All                                                   
                  values have six places and, for the SSN, begin with 7.  For                                                     
                  P/Giacobini-Zinner, file numbers are in the range of 700100 to                                                  
                  700999.                                                                                                         
                                                                                                                                  
                                                                                                                                  
DATE-OBS   C    Universal Time [UT] date of middle of data acquisition.  Date is                                                  
                  given in the FITS standard of day, month, year (DD/MM/YY).                                                      
                                                                                                                                  
TIME-OBS   F    Fractional part of day, indicating the UT time of the middle of                                                   
                  data acquisition.  The keyword has a value ranging from 0.0 to                                                  
                  0.99999.                                                                                                        
                                                                                                                                  
DATE-REL   C    Date the submitter or submitters agree to release their data to                                                   
                  the public.                                                                                                     
                                                                                                                                  
DISCIPLN   C    IHW Discipline.  For the SSN the value is always SPECTROSCOPY.                                                    
                                                                                                                                  
LONG-OBS   C    East longitude of observation station.  Keyword value range is                                                    
                  from 00/00/00 to 359/59/59.                                                                                     
                                                                                                                                  
LAT--OBS   C    Latitude of observation station.  Degrees north or south are                                                      
                  indicated by a preceding '+' or '-', respectively, 0 has no                                                     
                  sign.                                                                                                           
                                                                                                                                  
SYSTEM     C    Station system code.  Keyword is a number of the form 7nnnttii,                                                   
                  where:                                                                                                          
                                                                                                                                  
                  7 = Discipline number (SSN)                                                                                     
                  nnn = IAU Observatory Number                                                                                    
                  tt = Telescope Number, as assigned by the IHW Large Scale                                                       
                    Phenomena Network (LSPN)                                                                                      
                  ii = Instrument/Detector Number, assigned by the SSN, and                                                       
                    corresponds to DD in DIS-CODE keyword                                                                         
                                                                                                                                  
OBSERVER   C    Name of observer.  If more than two observers, first observer                                                     
                  listed, followed by ET AL.  Additional observers are listed                                                     
                  in COMMENT ADD.OBS. keyword.                                                                                    
                                                                                                                                  
SUBMITTR   C    Name of person or persons who submitted the data to the IHW SSN.                                                  
                                                                                                                                  
SPEC-EVT   L    If true, some special event occurred during observation.  See                                                     
                  COMMENTs and HISTORYs for more information.                                                                     
                                                                                                                                  
DAT-FORM   C    Form of the data.  One of: ASCII, STANDARD, HARDCOPY, NODATA.                                                     
                                                                                                                                  
DAT-TYPE   C    Type of data being submitted.  One of: UNKNOWN, REDUCED DIGITAL,                                                  
                  RAW DIGITAL, PHOTOGRAPHIC, OBJECTIVE PRISM, INTERFEROMETRIC,                                                    
                  SPACE BORNE.                                                                                                    
                                                                                                                                  
DIS-CODE   C    This keyword contains a 9-digit integer with the digits defined                                                   
                  as DDCCWWWRQ, where:                                                                                            
                                                                                                                                  
                  DD = Detector/Instrument combination.  This is a unique number                                                  
                    for each combination and has been assigned by the SSN.  This                                                  
                    value is the same as ii in the SYSTEM code.                                                                   
                                                                                                                                  
                  CC = Configuration (grating, grating tilt, filter, aperture                                                     
                    size, order, etc.) for given telescope and detector/instru-                                                   
                    ment combination.                                                                                             
                                                                                                                                  
                  WWW = Wavelength range [Angstrom], included in data.  A binary                                                  
                    coding scheme is used to specify a unique number for a                                                        
                    unique set of wavelength regions.  The number is the sum of                                                   
                    all defined values for each spectral region in which data                                                     
                    are submitted:                                                                                                
                                                                                                                                  
                    1 = <3000                                                                                                     
                    2 = 3000-3499                                                                                                 
                    4 = 3500-3999                                                                                                 
                    8 = 4000-4999                                                                                                 
                    16 = 5000-5999                                                                                                
                    32 = 6000-6999                                                                                                
                    64 = 7000-7999                                                                                                
                    128 = 8000-10000                                                                                              
                    256 = >10000                                                                                                  
                                                                                                                                  
                  Example: for 3700-6400 A, WWW = 4+8+16+32 = 60.                                                                 
                                                                                                                                  
                  R = Resolution.  This parameter is based on the spectral                                                        
                    resolution (FWHM in Angstrom).                                                                                
                                                                                                                                  
                    1 = <= 0.05                                                                                                   
                    2 = > 0.05 - 0.2                                                                                              
                    3 = > 0.2 - 1                                                                                                 
                    4 = > 1 - 5                                                                                                   
                    5 = > 5 - 10                                                                                                  
                    6 = > 10 - 20                                                                                                 
                    7 = > 20 - 50                                                                                                 
                    8 = > 50 - 100                                                                                                
                    9 = > 100                                                                                                     
                                                                                                                                  
                  Q = Quality of the data. We adopted a qualitative judgement                                                     
                    for this parameter, and the values are the same as the                                                        
                    QUALITY keyword.                                                                                              
                                                                                                                                  
                    0 = Unknown                                                                                                   
                    1 = Excellent                                                                                                 
                    2 = Very Good                                                                                                 
                    3 = Good                                                                                                      
                    4 = Fair                                                                                                      
                    5 = Poor                                                                                                      
                                                                                                                                  
                The files CODE.* contain a full listing of the discipline                                                         
                  codes used for P/Giacobini-Zinner, as well as the components                                                    
                  which define the DIS-CODE values.  These files may be read                                                      
                  into a database program, and used to translate DIS-CODE                                                         
                  values.                                                                                                         
                                                                                                                                  
OBSVTORY   C    Name of observatory from which data were obtained.                                                                
                                                                                                                                  
ELEV-OBS   F    Elevation of the observing station [m].                                                                           
                                                                                                                                  
TELESCOP   C    Telescope used for observation.  Where possible, the telescope                                                    
                  name as listed in the Astronomical Almanac has been used.                                                       
                                                                                                                                  
INSTRUME   C    Instrument and detector used to obtain data.                                                                      
                                                                                                                                  
RESOL-SP   C    Approximate spectral resolution of data [Angstrom].                                                               
                                                                                                                                  
RANGE-SP   C    Approximate spectral range of data [Angstrom].                                                                    
                                                                                                                                  
EXPOSURE   F    Exposure or integration time [s].                                                                                 
                                                                                                                                  
APERSIZE   C    Entrance aperture size or slit width and length of instrument                                                     
                  or detector [arcsec].                                                                                           
                                                                                                                                  
Airmass    F    One of the following:                                                                                             
                                                                                                                                  
                  AIRM-BEG = Airmass at beginning of observation.                                                                 
                  AIRM-END = Airmass at end of observation.                                                                       
                  AIRM-MID = Airmass at midpoint of observation.                                                                  
                  AIRM-AVE = Average of airmass of observation.                                                                   
                                                                                                                                  
SEPNUC     F    Separation between the comet nucleus and center of slit or                                                        
                  aperture [arcsec]; see Fig. 2.                                                                                  
                                                                                                                                  
ORIENT     F    Position angle of slit or aperture center with respect to the                                                     
                  comet's nucleus, measured north through east, ranging from                                                      
                  0 to 360 deg; see Fig. 2.                                                                                       
                                                                                                                                  
                                                                                                                                  
                                          N                                                                                       
                                  ORIENT  ^                                                                                       
                                       |  |                                                                                       
                                       |  |                                                                                       
                            POSANG     | /|      Tail                                                                             
                               \    N  |/ |     /                                                                                 
                  E <---        \   ^  (  *=======                                                                                
                                 \  |   \/ \                                                                                      
                                  \ |   /   Nucleus                                                                               
                                 \ \|  /                                                                                          
                                  \^| /------ SEPNUC                                                                              
                                   \|/                                                                                            
                  Slit Center ------\                                                                                             
                                     \                                                                                            
                                      \---- Slit                                                                                  
                                       \                                                                                          
                                                                                                                                  
                     Fig. 2. Definition of angles.                                                                                
                                                                                                                                  
                                                                                                                                  
POSANG     F    Position angle of the slit measured north through east, ranging                                                   
                  from 0 to 360 deg.  Two-dimensional spectra only (Fig. 2).                                                      
                  See COMMENT and HISTORY sections for observers' variations of                                                   
                  this definition.                                                                                                
                                                                                                                                  
PIXSCALE   F    Image scale at detector [arcsec per pixel].  Two-dimensional                                                      
                  spectra only.                                                                                                   
                                                                                                                                  
QUALITY    I    A subjective, qualitative estimate of the data.  Values used:                                                     
                  UNKNOWN, EXCELLENT, VERY GOOD, GOOD, FAIR, and POOR.                                                            
                                                                                                                                  
CTYPEn     C    n is a number between 1 and NAXIS.  Name of the independent                                                       
                  variables:                                                                                                      
                                                                                                                                  
                  LAMBDAA = Wavelength [Angstrom].                                                                                
                  VELOCITY = Velocity [km/s].                                                                                     
                  PIXELS = Pixel number.                                                                                          
                  RHO = Projected distance [arcsec].                                                                              
                  OTHER = Described in a comment.                                                                                 
                                                                                                                                  
BUNIT      C    Name of dependent variable:                                                                                       
                                                                                                                                  
                  FLAMBDA = Flux per wavelength [erg/cm2/s/Angstrom].                                                             
                  FNU = Flux per frequency [erg/cm2/s/Hz].                                                                        
                  RAYLAMBDA = Flux per wavelength [Rayleighs/Angstrom].                                                           
                  RELINS = Relative intensity.                                                                                    
                  COUNTS = Counts or count rate [counts/s].                                                                       
                  DENSITY = Photographic density.                                                                                 
                  OTHER = Described in a comment.                                                                                 
                                                                                                                                  
CRVALn     F    Reference point for CTYPEn.                                                                                       
                                                                                                                                  
CRPIXn     F    Reference pixel location corresponding to CRVALn.                                                                 
                                                                                                                                  
CDELTn     F    Increment in CTYPEn per pixel.                                                                                    
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
          In addition the FITS headers include a number of HISTORY, COMMENT, and                                                  
related keywords.  They are listed in Table V.                                                                                    
                                                                                                                                  
                                                                                                                                  
Table V. HISTORY, COMMENT, and related keywords in the FITS headers                                                               
________________________________________________________________________________                                                  
                                                                                                                                  
Keyword                         Type  Description                                                                                 
________________________________________________________________________________                                                  
                                                                                                                                  
HISTORY DATE-REC                  C   Date the file was received by the SSN.                                                      
                                                                                                                                  
HISTORY DATE-CMP                  C   Date of completion of the file archiving.                                                   
                                                                                                                                  
HISTORY REDUCED                   C   Known data reduction steps.                                                                 
                                                                                                                                  
HISTORY                           C   Other history if known.                                                                     
                                                                                                                                  
COMMENT ADD.OBS.                  C   Additional observers.                                                                       
                                                                                                                                  
COMMENT NOTE                      C   Some important note on the data extracted                                                   
                                        from COMMENT or HISTORY fields to appear                                                  
                                        in the printed archive listing.                                                           
                                                                                                                                  
COMMENT PROC FILE and ORIG. FILE  C   Comment regarding original file identifi-                                                   
                                        cation of the submitted file.  Often                                                      
                                        file name consists of position of file                                                    
                                        on original submission tape.  Used for                                                    
                                        SSN archiving.                                                                            
                                                                                                                                  
COMMENT REPLACE                   C   A note that this file supercedes another                                                    
                                        file (previous file would have been                                                       
                                        deleted from the archive).                                                                
                                                                                                                                  
COMMENT                           C   Additional comments about the data.                                                         
                                                                                                                                  
DATAMAX                           F   Maximum value of dependent variable.                                                        
                                                                                                                                  
DATAMIN                           F   Minimum value of dependent variable.                                                        
                                                                                                                                  
BSCALE                            F   Scale factor to convert FITS pixel values                                                   
                                        to true values.  Used to convert FITS                                                     
                                        data to original data values:                                                             
                                        DataValue = BZERO + BSCALE*FileDataValue                                                  
                                                                                                                                  
BZERO                             F   Offset applied to true pixel values.                                                        
                                                                                                                                  
END                               C   Signals end of FITS header.                                                                 
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
V. SSN OBSERVERS                                                                                                                  
                                                                                                                                  
          This archive was made possible thanks to the contributions by the 27                                                    
participating observers from three countries.  The names and affiliations of                                                      
these observers are listed in Table VI.                                                                                           
                                                                                                                                  
                                                                                                                                  
Table VI.  List of Observers                                                                                                      
________________________________________________________________________________                                                  
                                                                                                                                  
Observer          Affiliation                           Country                                                                   
________________________________________________________________________________                                                  
                                                                                                                                  
A'Hearn, M.     University of Maryland                  U.S.A.                                                                    
Barker, E.      University of Texas at Austin           U.S.A.                                                                    
Belton, M.      Kitt Peak National Observatory/NOAO     U.S.A.                                                                    
Boehnhardt, H.  Max-Planck-Institut fuer Aeronomie      Federal Republic Germany                                                  
Cochran, A.     University of Texas at Austin           U.S.A.                                                                    
Cochran, Wm.    University of Texas at Austin           U.S.A.                                                                    
DiSanti, M.     LPL, University of Arizona              U.S.A.                                                                    
Feldman, P.     Johns Hopkins University                U.S.A.                                                                    
Festou, M.      Observatoire de Besancon                France                                                                    
Filippenko, A.  University of California at Berkeley    U.S.A.                                                                    
Fink, U.        LPL, University of Arizona              U.S.A.                                                                    
Green, J.       University of Texas at Austin           U.S.A.                                                                    
Konno, I.       Arizona State University                U.S.A.                                                                    
Larson, S.      LPL, University of Arizona              U.S.A.                                                                    
Lutz, B.        Lowell Observatory                      U.S.A.                                                                    
McCarthy, P.    Las Campanas/Mt. Wilson Observatories   U.S.A.                                                                    
McFadden, L.    University of California at San Diego   U.S.A.                                                                    
O'Dell, C.R.    Rice University                         U.S.A.                                                                    
Sargent, W.     Palomar Observatory, Caltech            U.S.A.                                                                    
Sawyer, S.      University of Texas at Austin           U.S.A.                                                                    
Sonneborn, G.   NASA Goddard Space Flight Center        U.S.A.                                                                    
Spinrad, H.     University of California at Berkeley    U.S.A.                                                                    
Strauss, M.     University of California at Berkeley    U.S.A.                                                                    
Tegler, S.      Arizona State University                U.S.A.                                                                    
Wagner, R.M.    Lowell Observatory                      U.S.A.                                                                    
Wehinger, P.    Arizona State University                U.S.A.                                                                    
Wyckoff, S.     Arizona State University                U.S.A.                                                                    
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
ACKNOWLEDGMENTS                                                                                                                   
                                                                                                                                  
          Besides the members of the Discipline Specialist Team (Table I), the                                                    
following individuals also participated in archiving the SSN P/Giacobini-Zinner                                                   
data.  They contributed greatly to the completion of the archive: K. Byard, L.                                                    
Engel, I. Kono, E. Lindholm, L. McKibben, B. Pfarr, D. Reisinger, D. Schleicher,                                                  
S. Tegler, J. Theobald, R.M. Wagner, and  M. Womack.                                                                              
                                                                                                                                  
                                                                                                                                  
REFERENCE                                                                                                                         
                                                                                                                                  
Wells, D.C., Greisen, E.W., and Harten, R.H. (1981).  Astron. Astrophys. Suppl.                                                   
        Ser. 44, 363.