***** File FITSHDRS.TXT                                                       
                                                                              
A selected sample of FITS headers for the nine IHW Disciplines follows:       
                                                                              
                                                                              
                        1.0. ASTROMETRY                                       
                                                                              
                                                                              
Table 1.1.  Header Keyword Information                                        
                                                                              
______________________________________                                        
Keyword and Its Content                                                       
______________________________________                                        
                                                                              
SIMPLE  =                    T                                                
BITPIX  =                    8                                                
NAXIS   =                    1                                                
NAXIS1  =                 2880                                                
OBJECT  = 'P/HALLEY'                                                          
FILE-NUM=               102008                                                
DATE-OBS= '12/ 8/85'                                                          
TIME-OBS=              0.88403                                                
DATE-REL= '26/ 9/89'                                                          
DISCIPLN= 'ASTROMETRY'                                                        
LONG-OBS= '116/ 8/24'                                                         
LAT--OBS= '-32/00/30'                                                         
EQUINOX = 'B1950.0'                                                           
SYSTEM  = '18070000'                                                          
OBSERVER= 'CANDY,M.P ET AL.'                                                  
SUBMITTR= 'WIMBERLY,R.N'                                                      
SPEC-EVT=                    F                                                
DAT-FORM= 'ASCII   '                                                          
COMMENT  ADD. OBS.:    SMITH,P/DOE,J                                          
COMMENT  NOTES: VERY FAINT IMAGE                                              
END                                                                           
______________________________________                                        
                                                                              
                                                                              
     SYSTEM (C) is the system code in which the leading digit (1) identifies  
the Astrometry Network and the following three digits are a unique code for   
the reporting observatory (see Table VI).  The trailing four digits are zeroes
for the Astrometry Network.  OBSERVER (C) gives the name(s) of the            
observer(s), last name first followed by the initial(s) of their first (and   
middle) name(s) (see Tables VI and VII).  The observers are separated by a    
slash (/), whereas ET AL. indicates that additional observers (ADD. OBS.) are 
listed after the COMMENT keyword.  Problems with the observation or data      
reduction process also are identified after a keyword COMMENTS.  SUBMITTR (C) 
is R.N. Wimberly as the person who prepared the original data archive tape and
submitted it to the IHW Lead Center at JPL.  The SPEC-EVT (L) keyword is not  
used in the Astrometry Network. DAT-FORM (C) describes the format of the FITS 
data record, which for Astrometry is to be interpreted as logical records of  
80 ASCII characters.                                                          
__________________________________________________________________________    
                                                                              
                                                                              
                                                                              
                  2.0. INFRARED STUDIES                                       
                                                                              
                                                                              
Table 2.1. Keywords in the FITS Primary Headers(1)                            
                                                                              
______________________________________________________________________________
Keyword             Description                                               
______________________________________________________________________________
                                                                              
SIMPLE              Conformity to FITS format (T = yes, F = no)               
BITPIX              Number of bits/pixel                                      
NAXIS               Number of axes in array                                   
NAXIS1              Data array size, axis 1                                   
NAXIS2              Data array size, axis 2                                   
EXTEND              Conformity with (new) extension standard (T = yes, F = no)
OBJECT              Name of object                                            
FILE-NUM            File identification number                                
DATE-OBS            Date of middle of observation (UT) (dd/mm/yy)             
TIME-OBS            Time of middle of observation (expressed in decimal days  
                      UT)                                                     
DATE-REL            Date when observation may be publicly released (dd/mm/yy) 
DISCIPLN            IHW Discipline (IR STUDIES)                               
LONG-OBS            East longitude of observatory (0-360 deg)                 
LAT--OBS            Latitude of observatory (+ = north, - = south)            
SYSTEM              Observing system code 2NNNXXYY, where 2 denotes the IR    
                      Studies Network, NNN the IAU observatory code (= 500 if 
                      not in IAU list), XX the telescope number as collated by
                      LSPN (if NNN = 500, XX = country code), and YY not used 
OBSERVER            Observer(s) name(s)                                       
SUBMITTR            Submitter(s) name(s)                                      
SPEC-EVT            Special event (T = yes, F = no)                           
DAT-FORM            Form of data: 'STANDARD' if data records conform to FITS  
                      standard, 'ASCII' for tables, or 'NODATA' if data were  
                      not submitted                                           
DAT-TYPE            Type of data being submitted                              
OBSVTORY            Name of submitting observatory                            
LOCATION            Location of submitting observatory                        
TELESCOP            Telescope identification (size)                           
INSTRUME            Instrument used                                           
COMMENT             Cols. 9-80 are a comment                                  
HISTORY             Cols. 9-80 are a comment                                  
FILTER              Type of filter used                                       
APERSIZE            Entrance aperture size (arcsec)                           
AIRM-AVG            Average airmass of observation                            
RANGE-SP            Approximate spectral range (microns)                      
RESOL-SP            Approximate spectral resolution (microns)                 
DIS-CODE            Filter table number (in filter table files)               
BSCALE              Scale factor used to convert tape pixel values to true    
                      values (true = tape * BSCALE + BZERO)                   
BZERO               Offset applied to tape pixel values to convert to true    
                      values                                                  
BUNIT               Data units                                                
BLANK               Missing pixel filler value                                
CDELTn              Pixel spacing along axis n of data array                  
CTYPEn              Units along data axis n                                   
CRPIXn              Pixel number of nucleus along axis n                      
PIXSCALE            Pixel size in arcsec                                      
DATAMIN             Minimum data value in the file                            
DATAMAX             Maximum data value in the file                            
END                 End of FITS header                                        
______________________________________________________________________________
                                                                              
(1) Table extension keywords are defined and formatted in each file.          
                                                                              
                                                                              
                                                                              
                                                                              
                        3.0. LARGE-SCALE PHENOMENA NETWORK                    
                                                                              
                                                                              
Table 3.1.  Sample FITS header for Large-Scale Phenomena                      
                                                                              
______________________________________________________________________________
Keyword    Content                Explanation                                 
______________________________________________________________________________
                                                                              
SIMPLE  =                    T  / BASIC FITS FORMAT                           
BITPIX  =                   16  / 2-BYTE TWO'S COMPL INTEGERS                 
NAXIS   =                    2  / NUMBER OF AXES, 2=SINGLE IMAGE, 3=MULTIPLE  
NAXIS1  =                 4096  / PIXELS PER ROW                              
NAXIS2  =                 3072  / LINES PER IMAGE                             
OBJECT  = 'P/HALLEY          '  / NAME OF OBJECT                              
FILE-NUM=               300691  / NUMBER OF FILE SENT TO JPL, DNNNNN          
DATE-OBS= '20/03/86          '  / DATE OF MID-EXPOSURE DD/MM/YY               
TIME-OBS=              0.29028  / TIME OF MID-OBSERVATION, DAY FRACTION       
DATE-REL= '07/31/90          '  / DATA RELEASE DATE, DD/MM/YY                 
DISCIPLN= 'LARGE SCALE PHEN  '  / IHW NETWORK                                 
LONG-OBS= '289/11/07         '  / STATION LONGITUDE DDD/MM/SS                 
LAT--OBS= '-30/09/55         '  / STATION LATITUDE SDD/MM/SS                  
SYSTEM  = '38070400          '  / OBSERVING SYSTEM CODE                       
OBSERVER= 'MILLER,F          '  / NAME OF OBSERVER WHO TOOK PLATE             
SUBMITTR= 'NIEDNER,M         '  / LSPN SUBMITTER                              
SPEC-EVT=                    T  / SPECIAL EVENTS FLAG                         
DAT-FORM= 'STANDARD          '  / STANDARD FITS DATA                          
DAT-TYPE= 'IMAGE             '  / TYPE OF FITS DATA                           
LSPNSEQ =               110331  / SEQUENCE # OF PLATE RECEIVED AT LSPN        
OBSVTORY= 'UNIVERSITY OF MICHIGAN/CTIO             ' / NAME OF OBSERVATORY    
LOCATION= 'LA SERENA, CHILE  '  / STATION LOCATION - ADDRESS                  
TELESCOP= 'CURTIS SCHMIDT    '  / TYPE OF TELESCOPE                           
APERTURE=                0.610  / APERTURE, METERS                            
FRATIO  =                3.500  / EFFECTIVE TELESCOPE F RATIO                 
FOV1    =                5.000  / RA FIELD OF VIEW, DEGREES                   
FOV2    =                5.000  / DEC FIELD OF VIEW, DEGREES                  
PLTSZE1 =                0.203  / X PLATE SIZE, METERS                        
PLTSZE2 =                0.203  / Y PLATE SIZE, METERS                        
PLTSCALE=               96.661  / PLATE SCALE ARC SECONDS PER MM              
CALAVL  =                    T  / CALIBRATION AVAILABLE                       
HYPSEN  =                    T  / HYPERSENSITIZATION                          
EMULSION= 'IIA-O             '  / EMULSION TYPE                               
FILTER  = 'NONE              '  / TYPE OF FILTER USED                         
PLTYPE  =                    T  / PLATE TYPE, T=ORIGINAL, F=COPY              
EXPOSURE=                1200.  / EXPOSURE TIME, SECONDS                      
HISTORY   OBSLOG  = '29953   '  / ORIGINAL OBSERVATORY PLATE                  
BSCALE  =                  1.0  / SCALE FACTOR, TRUE = TAPE * BSCALE + BZERO  
BZERO   =                  0.0  / OFFSET FOR TRUE PIXEL VALUE                 
BUNIT   = 'DENSITY           '  / UNITS OF PIXEL VALUES                       
HISTORY   SCNAPR  =   40        / PDS SCAN APERTURE, MICRONS                  
HISTORY   SCNSTP  =   40        / PDS SCAN STEP, MICRONS                      
HISTORY   SKYDEN  =  190        / SKY BKGND PDS DENSITY                       
HISTORY   SKYUNF  = 'EXCL    '  / SKY BKGND POOR/FAIR/GOOD/EXCL               
CTYPE1  = 'RA---ARC          '  / X AXIS UNITS                                
CTYPE2  = 'DEC--ARC          '  / Y AXIS UNITS                                
EQUINOX =               1950.0  / EQINOX OF COORDINATE SYSTEM                 
RA--CPME=         0.293700E+03  / RA PLATE CENTER MID-EXPOSURE                
DEC-CPME=        -0.264086E+02  / DEC PLATE CENTER MID-EXPOSURE               
CRPIX1  =         0.162615E+04  / REF POINT FOR AXIS1, SAMPLES                
CRPIX2  =         0.148793E+04  / REF POINT FOR AXIS2, LINES                  
CDELT1  =        -0.107401E-02  / RA PER PIXEL, DEGREES                       
CDELT2  =        -0.107401E-02  / DEC PER PIXEL, DEGREES                      
CROTA1  =         0.121025E+00  / ROTATION ANGLE IN RA, DEGREES               
CROTA2  =         0.121025E+00  / ROTATION ANGLE IN DEC, DEGREES              
SENSE   =                    T  / SENSE OF ROTATION, T=CCW, F=CW              
CRVAL1  =         0.293700E+03  / RA AT REFERENCE POINT, DEGREES              
CRVAL2  =        -0.264086E+02  / DEC AT REFERENCE POINT, DEGREES             
RA--HEAD=         0.295308E+03  / RA COMET HEAD MID-EXPOSURE                  
DEC-HEAD=        -0.261628E+02  / DEC COMET HEAD MID-EXPOSURE                 
DATE-REC= '04/06/87          '  / DATE PLATE WAS RECEIVED AT GSFC, DD/MM/YY   
HISTORY   DATE-PDS= '20/03/87'  / DATE DIGITIZED DD/MM/YY                     
HISTORY   DATE-PRC= '13/07/88'  / DATE PROCESSED/CALIBRATED DD/MM/YY          
QUALITY = '123               '  / QUAL OF PLATE,GUIDING,TRAILS,SEEING,TRANSP  
END                                                                           
______________________________________________________________________________
                                                                              
                                                                              
     SYSTEM is a code denoting the observatory and the instrument used to     
obtain the image, and the location of the observing site.  The archive user is
referred to the LSPNOBS.TXT file in the DOCUMENT directory of the set of L-SP 
compressed image discs, HAL_0001 through HAL_0018.  Detailed information      
associated with each SYSTEM code can be found there, information which is also
contained in the delimited index LSPNOBS.IDX in the INDEX directory on those  
same discs.  A file listing observatory information across all IHW disciplines
is OBSCODES.TXT, which has been deposited in the DOCUMENT directory of these  
"mixed discs" (HAL_0019--HAL_0023).                                           
                                                                              
     SPEC-EVT is a keyword signifying the presence or absence of a "special   
event", and is either "T" or "F" in value.  In nearly all cases it was the    
L-SP Discipline Specialist (M. Niedner) who evaluated the imagery and set this
parameter.  Disconnection events (DEs) in the plasma tail, strong bursts of   
tail ray generation, and large amplitude bends in the tail, are but a few of  
the situations meriting a SPEC-EVT = T.  The classification is obviously      
somewhat subjective and the DS should not be held responsible for database    
searches of NETLARGE.IDX (resident in the INDEX directory of the compressed   
image discs) keyed solely to SPEC-EVT; it is a coarse parameter that is meant 
only to signify possible interest in an image.                                
                                                                              
     PLTSCALE should be used with caution.  It does indicate plate scale, but 
only for original plates or films.  Moreover, it is derived from the focal    
length of the telescope, not astrometrically, and hence never varies from one 
original image to the next taken on the same telescope.  In some cases, most  
notably 35mm film negatives on Kodak Technical Pan 2415, the digital scan was 
made of a greatly enlarged film copy of the original small frame.  In this    
case PLTSCALE is not remotely close to the scale of the digital image.   We   
have provided a rigorous astrometric plate solution for each scanned image,   
and the true "digital image scale" is contained in other FITS keywords        
(CDELT1,2 and SCNSTP, described below).                                       
                                                                              
     CALAVL is a keyword signifying the existence or absence of calibration   
data associated with the Halley image.  A value of "T" does not, however,     
necessarily mean that the calibration information resides on these CD-ROMs,   
because not all calibration plates were digitized by the L-SP Team.  Refer to 
the text file CALIB_LS.TXT in the DOCUMENT directory of these "mixed discs"   
(or to the CALIB.TXT file on the compressed image discs) for a discussion of  
which calibration data were included in the archive.  The filenames of        
calibration datafiles in the archive are contained in text tables in          
CALIB_LS.TXT and in delimited index table CALIB_LS.IDX of directory INDEX.    
                                                                              
     PLTYPE designates whether the digitized image was an original plate or   
film ("T") or a copy ("F") made by either the contributing observer or by the 
L-SP Team.  In the latter category it should be mentioned that in some cases  
the observer sent the DS a film copy of sufficient quality for scanning, and  
in other situations it was necessary to enlarge original small images prior to
digitization.                                                                 
                                                                              
     CRPIX1,2....CRVAL1,2 form a block of "astrometric keywords", the names   
and meanings of most of which are identical to keywords defined by Wells et   
al. (1981).  Briefly, CRPIX1 and CRPIX2 fix the location of the upper-left    
(NE) corner of the scan area relative to the reference position, in numbers of
samples and lines, respectively.   We have adopted the plate center as the    
reference position, or "reference pixel" as it is called.  CDELT1 and CDELT2  
are self-explanatory, but it should be noted that the "classical" plate scale 
in arcsec/mm can be derived from CDELT1(,2) and SCNSTP (scan step in microns) 
if one wishes it.                                                             
                                                                              
     CROTA1 and CROTA2 were not tightly defined in the original FITS paper    
(Wells, D.C., et al.,1981), so we wish to be specific here about how the      
angles are measured.   First, we define CROTA1=CROTA2, always.  The angle(s)  
refer to the rotation of the X-Y PDS (microdensitometer) coordinate frame     
relative to the axes of the celestial coordinate system.  The Large-Scale     
Phenomena Appendix, LS_PHEN.APX (resident in the DOCUMENT\APPENDIX directory),
contains a pictorial diagram to which the Archive user may wish to refer.  To 
reasonable accuracy, the +Y scanning axis is in the direction of North at the 
plate center, for the epoch of 1950.0.  The +X scanning axis is in the        
approximate direction of due East (again, at the plate center for 1950.0).  As
a result of the inevitable human error in positioning the plate on the PDS    
platen, however, there will be a non-zero rotation angle offset (very small)  
between the two coordinate systems.  When the North direction lies in the     
+X/+Y quadrant, i.e., is rotated in a counterclockwise direction relative to  
the +Y axis, we say that the rotation angles CROTA1 and CROTA2 are both       
positive (and the same value).  A positive angle for such a counterclockwise  
rotation is what is meant by SENSE = T, and we adopt SENSE = T throughout this
archive. Because of its redundancy, the keyword SENSE is not indexed in       
NETLARGE.IDX, although it is present in the individual FITS headers.          
                                                                              
     CRVAL1 and CRVAL2 are the right ascension and declination of the         
reference position, which we have made the plate center.  Note that these     
coordinates are separately given as RA--CPME and DEC-CPME, the formal         
coordinates of the plate center.                                              
                                                                              
     RA--HEAD and DEC-HEAD are the measured (approximate) coordinates of the  
head center, but are not given in either the FITS headers or the appropriate  
lines in the index table for those plates which did not contain the head      
region. Note that the head center coordinates are for reference purposes only 
and are not to be used for accurate positions of the nucleus; well-saturated, 
wide-field plates are obviously not suitable for that purpose. QUALITY is a   
keyword which gives a very subjective assessment of the condition of each     
scanned image in terms of five categories (plate, guiding, trails, seeing, and
transparency); the scale is 1-5 (excellent to poor).  Not for all plates was  
it possible to evaluate each category, and hence the archive user will        
occasionally come across (for example) QUALITY = '123  '.                     
                                                                              
                                                                              
                                                                              
                                                                              
                            4.0. NEAR NUCLEUS                                 
                                                                              
                                                                              
Table 4.1. The NNSN Header Keywords                                           
                                                                              
______________________________________________________________________________
                                                                              
SIMPLE  =                    T /T conforms to standard FITS format            
BITPIX  =                   16 /16 (or 32)-bit data                           
NAXIS   =                    2 /number of axes in array                       
NAXIS1  =                 ____ /number of pixels in X axis (samples)          
NAXIS2  =                 ____ /number of pixels in Y axis (rows)             
OBJECT  = 'P/HALLEY'           /object name                                   
FILE-NUM=               4_____ /file number                                   
DATE-OBS= '__/__/__'           /mid-UT date of observation (dy/mo/yr)         
TIME-OBS=               ._____ /mid-UT decimal part of day                    
DATE-REL= '__/__/__'           /date released to archive (dy/mo/yr)           
DISCIPLN= 'NEAR NUCLEUS'       /IHW network                                   
LONG-OBS= '___/__/__'          /observatory east longitude (deg/min/sec)      
LAT--OBS= '___/__/__'          /observatory latitude (+-deg/min/sec)          
SYSTEM  = '4_______'           /observing system code                         
OBSERVER= '__________________' /observer's names (see ADD. OBS.:in COMMENT)   
SUBMITTR= '__________________' /submitter's names                             
SPEC-EVT=                    _ /T if jets present (10/85-6/86)                
DAT-FORM= 'STANDARD'           /type of data                                  
OBSVTORY= '__________________' /observatory name                              
ELEV-OBS=                 ____ /elevation of observatory in meters            
TELESCOP= '__________________' /telescope used                                
APERTURE=                 _.__ /telescope aperture in meters                  
TELEFL  =                _.___ /effective focal length in meters              
PLTSCALE=                __.__ /plate scale in arcsec per mm                  
CROTA1  =                ___._ /position angle of sample axis, north -> east  
SENSE   =                    _ /PA counterclockwise (T) or clockwise (F)      
DETECTOR= '__________________' /detector used                                 
DIGITIZE= '__________________' /type of digitizer used if not detector        
APSIZE  =                _.___ /original pixel size of detector/digitizer     
FILTER  = '______ '            /filter used (see Table IV)                    
EXPOSURE=               ____._ /exposure duration in seconds                  
AIRM-MID=                _.___ /calculated airmass at mid-exposure            
QUALITY = '_________'          /general quality of image                      
DATE-WRT= '__/__/__'           /date this file written                        
ORIGIN  = '__________________' /institution sending data to NNSN              
BUNIT   = '__________________' /intensity  units (note that BSCALE=1, BZERO=0)
COMETMAX=               ______ /approximate maximum value in comet image      
SKYMIN  =               ______ /approximate background sky brightness         
COMMENT (any comments relating to the image contents and additional observers)
HISTORY (any comments relating to the reduction process)                      
END                                                                           
_____________________________________________________________________________ 
                                                                              
                                                                              
     The 250 system codes are specific to any detector, array size, telescope,
optical configuration and filter, and are of the form 4NNNXXYY, where 4       
denotes the NNSN, NNN is the IAU observatory code, XX the telescope, and XX   
the filter/scale/array size configuration. A list of observers are associated 
with each system code, so more than one observer group may share a system     
code.                                                                         
                                                                              
     The quality rating is only a rough, qualitative guide that includes the  
effects of seeing, focussing, guiding, the signal-to-noise ratio, and         
decalibration. The four rating categories are excellent, good, fair, and poor:
excellent refers to images with no obvious flaws and poor denotes images      
included only because of the lack of better ones on that day. The user will   
have to gain some experience to know what to expect from the different grades.
                                                                              
     The airmass at mid-exposure (AIRM-MID) is calculated from current epoch  
topocentric comet coordinates (RA, DEC) and observatory coordinates (LONG,    
LAT) as:                                                                      
                                                                              
     AIRM-MID = sec Z - 0.0018167 (sec Z - 1) - 0.002875 (sec Z - 1)**2       
                                            - 0.0008083 (sec Z - 1)**3,       
where the zenith distance Z follows from:                                     
                                                                              
      sec Z = 1/[sin(LAT)*sin(DEC) + cos(LAT)*cos(DEC)*cos(local hour angle)].
                                                                              
The airmass at the zenith is 1, so it does not include a correction for the   
local elevation. Also note that there is no correction for apparent and true  
zenith distance.                                                              
                                                                              
                                                                              
                                                                              
                                                                              
                               5.0. PHOTOMETRY AND POLARIMETRY                
                                                                              
                                                                              
                                                                              
Table 5.1.  FITS Header Keywords                                              
                                                                              
______________________________________________________________________________
  Item         FITS Keyword  Format       Value/Explanation                   
______________________________________________________________________________
                                                                              
Comet Name      OBJECT       string       'P/HALLEY' for all                  
                                            files in this archive.            
File Number     FILE-NUM     I6           '56xxxx'                            
                                            5 ==> Photometry/Polarimetry      
                                                  Network                     
                                            6 ==> P/Halley                    
                                            xxxx = running number, not in     
                                                  chronological order         
Date            DATE-OBS     dd/mm/yy     Date of the observations            
UT Time         TIME-OBS     F6.5         Decimal fraction of the day at the  
                                            midpoint of the observations in   
                                            the table                         
UT Start Time   TIME-STR     F6.5         Decimal fraction of the day at the  
                                            start of the observations in the  
                                            table when available.             
Our Network     DISCIPLN     string       'PHOTOMETRY' for this Network       
Observatory     OBSVTORY     string       Name of observatory                 
   Longitude    LONG-OBS     ddd/mm/ss    Positive, eastward from Greenwich   
   Latitude     LAT--OBS     sdd/mm/ss    s='+' or '-' for North or South     
   Elevation    ELEV-OBS     I4           [m]                                 
   System       SYSTEM       I8           See Sec. 7                          
   Telescope    TELESCOP     string       A unique identification of the      
                                            telescope by name or size         
Type of data    DAT-TYPE     string       'POLARIMETRY', 'STOKES", 'BROADBAND'
                                            or 'NARROWBAND'. Note the tables  
                                            that follow 'Fluxes' refers to    
                                            'NARROWBAND' and 'Magnitudes'     
                                            refers to 'BROADBAND'             
Observer(s)     OBSERVER     string       Name(s) of observer(s) (omitted for 
                                            FES observations with IUE;large   
                                            team headed by Feldman & Festou)  
Submitter       SUBMITTR     string       Person who submitted data to the    
                                            DS.  A blank usually means data   
                                            were taken from the literature.   
Comments        COMMENT      string       All comments are character strings  
                                          (line = 80 characters) following the
                                          keywords 'COMMENT' and 'HISTORY'    
                                          and in some cases the following     
                                          secondary keywords:                 
                                          'LIT.' => reference from literature 
                                          'NOTE' => footnote to table         
                                          'NOTExx' => footnote to line xx     
                                          'ADD. OBS.' => names of additional  
                                            observers beyond those above      
                HISTORY      string       Comments relevant to calibration    
                                            'STDSTARS' => list of standard sta
s                                                                             
                                            used in the reduction. In case of 
                                            polarimetry standard stars POL-STD
                                            refers to highly polarized stars, 
                                            and UNPOL-STD to unpolarized stars
______________________________________________________________________________
                                                                              
                                                                              
     The FITS tables can take any of four different formats depending on the  
type of data in the table.  The types of table are known by the following     
values for the FITS 'DAT-TYPE' keyword: 'BROADBAND', 'NARROWBAND',            
'POLARIMETRY', and 'STOKES'.  Note that the value 'BROADBAND' is actually used
to indicate results given in magnitudes rather than fluxes.  It is independent
of the actual bandwidth of the filters used.  The first few columns in the    
tables are identical for all types of data and are listed in Table 5.2.       
Additional entries for DAT-TYPE = 'BROADBAND' are in Table 5.3, for DAT-TYPE =
'NARROWBAND' in Table 5.4, for DAT-TYPE = 'POLARIMETRY' in Table 5.5, and for 
DAT-TYPE= 'STOKES' in Table 5.6.                                              
                                                                              
                                                                              
                                                                              
Table 5.2.  Columns Common to All Types of Data                               
                                                                              
______________________________________________________________________________
Item                 Format    Columns        Explanation                     
______________________________________________________________________________
Date and time(UT)     F8.5      1 -   8       Day of month and decimal frac-  
                                                tion at mid-point of observa- 
                                                tion                          
Serial number         I2       10 -  11       Line number in the table        
                                                Occasional numbers are skipped
Filter name           A4       13 -  16       Short-hand name                 
       wavelength     I4       18 -  21       Central wavelength [A]          
       width          I4       23 -  26       FWHM [A]                        
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                                                                              
                                                                              
Table 5.3.  Columns for Magnitudes (DAT-TYPE = 'BROADBAND')                   
                                                                              
______________________________________________________________________________
Item                 Format    Columns        Explanation                     
______________________________________________________________________________
                                                                              
Upper limit code      char        28          '<' indicates that the result in
                                                the following field is a      
                                                3-sigma limit                 
Magnitude             F7.3     30 -  36       Reduced magnitude               
       error          F5.3     38 -  42       One (1) sigma [mag];            
                                                omitted if previous field is a
                                                limit                         
Aperture size         F5.1     44 -  48       Diameter [arcsec]               
Radial offset         I4       50 -  53       Radial distance between center  
                                                of aperture and the peak      
                                                brightness                    
                                                of the comet [arcsec]         
Offset direction      I3       55 -  57       Angular direction [deg]         
                                                (eastward from north)         
                                                of the radius vector to the   
                                                center of the aperture from   
                                                the peak in brightness        
Integration time      I4       59 -  62       Integration time [s]            
Airmass               F5.3     64 -  68       Airmass at midpoint in time,    
                                                usually as quoted by observer 
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                                                                              
Table 5.4.  Columns for Fluxes in Narrowband Filters (DAT-TYPE = 'NARROWBAND')
                                                                              
______________________________________________________________________________
Item                 Format    Columns        Explanation                     
______________________________________________________________________________
                                                                              
Upper limit code      char        28          '<' indicates that the result in
                                                the following field is a      
                                                3-sigma limit                 
Log Flux              F7.3     30 -  36       Logarithm (base 10) of the flux 
                                                See Sec. 4 for details        
        error         F5.3     38 -  42       Error of log10 of flux          
Aperture size         F5.1     44 -  48       Diameter [arcsec]               
Radial offset         I4       50 -  53       Radial distance between center  
                                                of aperture and the peak      
                                                brightness of the comet       
                                                [arcsec]                      
Offset direction      I3       55 -  57       Angular direction [deg]         
                                                (eastward from north)         
                                                of the radius vector to the   
                                                center of the aperture from   
                                                the peak in brightness        
Integration time      I4       59 -  62       Integration time [s]            
Airmass               F5.3     64 -  68       Airmass at midpoint in time     
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
Table 5.5.  Columns for Polarimetry in Percent (DAT-TYPE = 'POLARIMETRY')     
                                                                              
______________________________________________________________________________
Item                 Format    Columns        Explanation                     
______________________________________________________________________________
                                                                              
Polarization type     A2       28 -  29       'CR' => right circular          
                                              'CL' => left circular           
                                              'LN' => linear                  
Polarization value    F5.2     31 -  35       Degree of polarization [%]      
         error        F5.2     37 -  41       One (1) sigma [%]               
Position angle        F5.1     43 -  47       For linear polarization, the    
                                                position angle of the electric
                                                vector [deg] clockwise from   
                                                the plane of scattering       
                                                (-45 to +135)                 
         error        F4.1     49 -  52       One sigma                       
Aperture size         F5.1     54 -  58       Diameter [arcsec]               
Radial offset         I4       60 -  63       Radial distance between center  
                                                of aperture and the peak      
                                                brightness of the comet       
                                                [arcsec]                      
Offset direction      I3       65 -  67       Angular direction [deg]         
                                                (eastward from north)         
                                                of the radius vector to the   
                                                center of the aperture from   
                                                the peak in brightness        
Integration time      I4       69 -  72       Integration time [s]            
Airmass               F5.3     74 -  78       Airmass at midpoint in time,    
                                                usually as quoted by observer 
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                                                                              
Table 5.6.  Columns for Stokes Vectors (DAT-TYPE = 'STOKES')                  
                                                                              
______________________________________________________________________________
Item                 Format    Columns        Explanation                     
______________________________________________________________________________
                                                                              
Q/I                   F7.4     28 -  34       Normalized Stokes parameter Q/I,
                                                positive for the electric vec-
                                                tor perpendicular to the plane
                                                of scattering, negative for   
                                                the electric vector parallel  
                                                to the plane [dimensionless]  
         error        F6.4     36 -  41       One sigma                       
U/I                   F7.4     43 -  49       Normalized Stokes parameter U/I,
                                                positive for the electric vec-
                                                tor 45 deg counterclockwise   
                                                from positive values of Q,    
                                                negative for 45 deg clockwise 
                                                [dimensionless]               
         error        F6.4     51 -  56       One sigma                       
V/I                   F7.4     58 -  64       Normalized Stokes parameter V/I,
                                                positive for left handed as   
                                                seen by the observer, negative
                                                for right handed as seen by   
                                                the observer [dimensionless]  
         error        F6.4     66 -  71       One sigma                       
Aperture size         F5.1     73 -  77       Diameter [arcsec]               
Radial offset         I4       79 -  82       Radial distance between center  
                                                of aperture and the peak      
                                                brightness of the comet       
                                                [arcsec]                      
Offset direction      I3       84 -  86       Angular direction [deg]         
                                                (eastward from north)         
                                                of the radius vector to the   
                                                center of the aperture from   
                                                the peak in brightness        
Integration time      I4       88 -  91       Integration time [s]            
Airmass               F5.3     93 -  97       Airmass at midpoint in time,    
                                                usually as quoted by observer 
                                                                              
                                                                              
                                                                              
                                                                              
                              6.0. RADIO SCIENCE                              
                                                                              
                                                                              
Table 6.1. Keyword Block I                                                    
                                                                              
______________________________________________________________________________
Keyword  Type  Description                                                    
______________________________________________________________________________
                                                                              
SIMPLE    L    Conformity to basic FITS standards                             
BITPIX    I    Bits per pixel in data record                                  
NAXIS     I    Number of axes in data record; if NAXIS = 0 then no data record
NAXIS1    I    Number of pixels in row along first axis; if NAXIS1 = 0 then   
                 this is Extended FITS Format and GROUP data are present      
NAXISn    I    Number of pixels along n-th axis in image                      
OBJECT    C    Name of the object                                             
                    Examples: 'P/CROMMELIN'                                   
                              'P/HALLEY'                                      
                              'P/GIACOBINI-ZINNER'                            
FILE-NUM  I    6NNNNV - unique, sequential number to identify files sent to   
                    IHW Lead Center.  Format description:                     
                    6 = denotes Radio Science Network                         
                 NNNN = unique 4 digit ID number assigned to each observation 
                    V = version number (used to keep track of resubmissions)  
DATE-OBS  C    'DD/MM/YY' - UT date of middle of observation                  
                    if observations made during several intervals, then these 
                    intervals will be specified in the HISTORY fields         
                    described below                                           
TIME-OBS  R    UT time of middle of observation expressed in decimal days     
DATE-REL  C    'DD/MM/YY' - date when observations may be publicly released   
DISCIPLN  C    'RADIO STUDIES' - the Network identification                   
LONG-OBS  C    'DDD/MM/SS' - east longitude of observatory (0-360 deg)        
LAT--OBS  C    'sDD/MM/SS' - latitude of observatory                          
SYSTEM    C    '6OOOCCTT' - system code formatted:                            
                    6 = Radio Science Network                                 
                  OOO = IAU number for observatory                            
                        (OOO = 500 for radio observatories since no IAU number
                         exists)                                              
                   CC = identifies country according to LSPN Code             
                   TT = identifies radio telescope                            
OBSERVER  C    Name of observer                                               
                    Format : 'LASTNAME,I'            - 1 author               
                             'LASTNAME,I/NEXTNAME,J' - 2 authors              
                             'LASTNAME,I/ET AL.'     - >2 authors             
                    For more than 2 observers, the names of all additional    
                    observers are given in special ADD. OBS. comments         
SUBMITTR  C    Name of submitter of data                                      
SPEC-EVT  L    Flag for special events as designated by Discipline Specialist 
DAT-FORM  C    Describes format of FITS data records                          
               'NODATA  ' - no FITS data records written                      
               'STANDARD' - data records conform to FITS standard             
               'ASCII   ' - data records are to be interpreted as logical     
                            records of 80 ASCII characters (not FITS standard)
               'HARDCOPY' - data submitted as hardcopy                        
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
Table 6.2. Keyword Block III                                                  
                                                                              
______________________________________________________________________________
Keyword  Type  Description                                                    
______________________________________________________________________________
                                                                              
DIS-CODE  C    'TFESEWEABENC' - describes parameters of the telescope/        
                                instrument                                    
               T : Telescope type                                             
                    S = single antenna                                        
                    I = interferometer                                        
                    U = unknown/unclassified                                  
               FE: Frequency (Center Frequency or Rest Frequency)             
                    FE=> frequency = F x 10**(E) MHz                          
                    00=  unknown                                              
               SE: Spectral resolution                                        
                    SE=> spectral resolution = S x 10**(E) Hz                 
                    00=  unknown                                              
               WE: Bandwidth                                                  
                    WE=> bandwidth = W x 10**(E) Hz                           
                    00=  unknown                                              
               A : Beam description                                           
                    C = circular                                              
                    E = ellipitical                                           
                    O = other                                                 
                    U = unknown                                               
               BE: Beam size (geometric mean)                                 
                    BE=> beam size = B x 10**(E) arcsec                       
                    00= unknown                                               
               N : Noise estimate                                             
                    N => RMS noise = 10**(N) microJansky/beam                 
                    0 = unknown                                               
               C : Information provided by observer to Discipline Specialist  
                    is complete                                               
                    T = TRUE                                                  
                    F = FALSE                                                 
DAT-TYPE  C    'NNSTHP' - describes the data format in Header and Data Records
               NN: Subnetwork                                                 
                    OH= OH Subnetwork                                         
                         Spectral line observations of 18-cm OH               
                    SL= Spectral Line Subnetwork                              
                         Spectral line observations (other than 18-cm OH)     
                    CN= Continuum Subnetwork                                  
                         Broadband continuum observations                     
                    OC= Occultation Subnetwork                                
                         Observation of occultation events                    
                    RD= Radar Subnetwork                                      
                         Active experiments                                   
               S : Search/detection status                                    
                    S = search - implies nondetection (< 3 sigma)             
                    D = detection - implies detection (> 3 sigma)             
                    M = marginal - implies marginal detection (approx. 3      
                        sigma)                                                
               T : Type of data in FITS Data Records                          
                    N = no FITS Data Records                                  
                    S = Spectrum           => intensity vs frequency          
                    C = Continuum scan     => intensity vs space              
                    T = Time series        => intensity vs time               
                    I = Image              => spatial - spatial image         
                    D = Dynamic spectrum   => frequency - time image          
                    F = SV image           => frequency - spatial image       
                    V = Visibility Function Data                              
               H : Summary of Data in Header?                                 
                    T = Summary of data exists in Header History Section      
                    F = No summary of data in Header History Section          
               P : Polarization status                                        
                    I = Intensity data only                                   
                    P = Polarization data format used                         
OBSVTORY  C    Abbreviation for Observatory.                                  
TELESCOP  C    Telescope identifier - usually gives aperture size in meters   
LOCATION  C    Location of Observatory as given in American Ephemeris         
INSTRUME  C    'FRONT/BACK' - describes "frontend" and "backend" of receiver  
               FRONT: Receiver Front End                                      
                    MASER = Maser Amplifier                                   
                    FET   = Field Effect Transistor Amplifier                 
                    PARA  = Parametric Amplifier                              
                    MIXER = Mixer                                             
                    SPEC  = Special Front End                                 
                    UNK   = Unknown Front End                                 
               BACK  : Receiver Back End                                      
                    FB    = Filterbank                                        
                    SEFB  = Filterbank with Spectrum Expander                 
                    AC    = Autocorrelator                                    
                    CONT  = Broadband Continuum Receiver                      
                    SPEC  = Special Back End                                  
                    AOS   = Acousto-Optical Spectrometer                      
                    UNK   = Unknown Back End                                  
CENTFREQ  R    Center frequency of observed bandwidth (Hz)                    
BANDWIDT  R    Total bandwidth (Hz)                                           
BEAMSIZE  R    Geometric mean of major and minor axes of Elliptical Gaussian  
               Beam (deg)                                                     
BEAMELON  R    Ratio of major beam axis to minor beam axis                    
BEAMROTA  R    Position angle of major beam axis (deg)                        
BEAMEFF   R    Beam efficiency - fraction of power received that is in the    
               Gaussian Main Beam (BEAMEFF = 0.0 if unknown or unspecified)   
MOLECULE  C    Chemical formula for molecule (follows convention of NBS       
               interstellar-line list)                                        
TRANSITN  C    Quantum numbers for transition (follows convention of NBS      
               interstellar-line list)                                        
RESTFREQ  R    Rest frequency of line used by observer (Hz)                   
RES-SPEC  R    Spectral resolution (Hz) - true spectral resolution of the     
                 spectrometer, NOT the channel spacing                        
EQUINOX   R    Equinox of RA-DEC information presented in this file           
RAOFF     R    Pointing offset in RA direction DELTA(RA)*COS(DEC) (deg)       
DECOFF    R    Pointing Offset in Dec direction DELTA(DEC) (deg)              
DATE-BEG  C    'DD/MM/YY' - UT date on which observations began               
DATE-END  C    'DD/MM/YY' - UT date on which observations ended               
______________________________________________________________________________
                                                                              
                                                                              
     There is a group of COMMENT lines give additional information to be used 
in the production of the IHW printed archive.                                 
                                                                              
     The ADD. OBS. comment gives the names of the full observing team in the  
case that more than two observers carried out the observations.  More than one
ADD. OBS. comment may be used to specify teams with many members or long      
names. The format of the ADD. OBS. comment is: COMMENT   ADD. OBS.            
NAME,I/NAME2,I/NAME3,I                                                        
                                                                              
     The NOTE comment provides information that is to be printed as a footnote
in the printed archive in the following format:                               
                                                                              
COMMENT   NOTE      THIS IS A TEST                                            
                                                                              
     Next there are FITS HISTORY keywords provided to incorporate additional  
information about the observation, such as descriptions of calibration methods
and sources, details about observing procedures, and comments by the observer 
and the IHW Discipline Specialist.  Another important use of the HISTORY lines
is to provide a summary of the data obtained, or in the case of FITS files    
with no data records, the actual data values reported by the observer.  The   
general format of the HISTORY lines is:                                       
                                                                              
column                                                                        
1        11        21                                                         
HISTORY   SUBKEY__  VALUES....                                                
                                                                              
where values is a list of values associated with this subkey.  In most cases, 
the value lists are in a fixed format in order to simplify their use.         
                                                                              
     In order to transmit upper limits or a summary of the data that would be 
appropriate for tabular presentation in the printed archive, we utilize one of
the following HISTORY keyword formats.  Such summaries of the data will always
be contained in the first part of the HISTORY keyword section; the presence of
such a summary shall be indicated in the DAT-TYPE keyword discussed above.  In
the case where FITS data records accompany the header, USERS OF THE ARCHIVE   
ARE CAUTIONED THAT THE SUMMARY VALUES ARE ONLY MEANT TO DESCRIBE AND          
CHARACTERIZE THE DATA ... NOT TO REPLACE THEM.                                
                                                                              
     All summary lines follow the same general form:                          
                                                                              
HISTORY   SUBKEY    ################  'UNITS   '                              
                                                                              
where the # field is a right justified floating point number.                 
                                                                              
     Format for Upper Limits:                                                 
                                                                              
COMMENT             *SUMMARY OF DATA - UPPER LIMIT                            
HISTORY   LIMIT                  0.5  'JY/BEAM '                              
                                                                              
     Upper limits in the Radio Science Network are always given as 3 standard 
deviation upper limits.                                                       
                                                                              
     Format for Spectral Lines:                                               
                                                                              
COMMENT             *SUMMARY OF DATA - SPECTRAL LINE                          
HISTORY   LINEPEAK               0.5  'JY/BEAM '                              
HISTORY   ERR-PEAK               0.1  'JY/BEAM '                              
HISTORY   LINE-VEL              10.0  'M/SEC   '                              
HISTORY   ERR--VEL             200.2  'M/SEC   '                              
HISTORY   LINE-WID            2532.0  'M/SEC   '                              
HISTORY   ERR--WID             130.2  'M/SEC   '                              
HISTORY   LINEAREA            1243.1  'JY/B*M/S'                              
HISTORY   ERR-AREA             143.6  'JY/B*M/S'                              
HISTORY   LINEMEAN              32.1  'M/SEC   '                              
HISTORY   ERR-MEAN              10.2  'M/SEC   '                              
                                                                              
The spectral line summary values LINEPEAK, LINE-VEL, and LINE-WID are         
determined from gaussian fits to the line profiles.  If one or more parameters
were fixed in a fit to the data, the assumed values are listed with no errors.
Spectral lines with hyperfine structure (e.g., HCN) are fitted on the         
assumption that all hyperfine components have their nominal intensity ratios. 
                                                                              
     Format for Continuum Observations:                                       
                                                                              
COMMENT             *SUMMARY OF DATA - CONTINUUM                              
HISTORY   CONTFLUX               0.5  'JY/BEAM '                              
HISTORY   ERR-FLUX               0.1  'JY/BEAM '                              
                                                                              
     Format for Radar Observations:                                           
                                                                              
COMMENT             *SUMMARY OF DATA - RADAR                                  
HISTORY   XSECTION              30.0  'SQUARE KILOMETERS'                     
HISTORY   ERR-XSEC               6.0  'SQUARE KILOMETERS'                     
                                                                              
     Since many radio observations take place over several days, we include   
the precise observing windows in the HISTORY section according to the format: 
                                                                              
COMMENT             *OBSERVING WINDOW SPECIFICATION                           
HISTORY   N-WINDOW                 #                                          
HISTORY   WINDOW    'DD/MM/YY' #######     'DD/MM/YY' #######                 
HISTORY   WINDOW    'DD/MM/YY' #######     'DD/MM/YY' #######                 
                                                                              
where N-WINDOW gives the total number of windows for observation and          
subsequent window lines give the date and time (in decimals as in TIME-OBS) of
beginning and end of the observing window.  The time fields are right         
justified floating point numbers.                                             
                                                                              
     Radio observers track the comet "blind" and it is important to know the  
precise position on the sky that they were tracking.  We include a provision  
in the HISTORY section to specify the two-body elements and observatory       
position data used to produce the topocentric ephemeris for tracking.         
                                                                              
                                                                              
COMMENT             *ORBITAL ELEMENT SPECIFICATION                            
HISTORY   ORBELEM                  T     - T if orbital elements are provided 
HISTORY   LONGEAST      243.11046715     - east longitude of observatory (deg)
HISTORY   RHO--COS      0.8159113419     - radius*cos(lat) for observatory    
                                           (units of Earth equatorial radius) 
HISTORY   RHO--SIN      0.5765085118     - radius*sin(lat) for observatory    
                                           (units of Earth equatorial radius) 
HISTORY   ET-UT             53.18439     - Ephemeris Time - UT correction (s) 
HISTORY   JD           2446471.16128     - Time of Perihelion passage (ET)    
HISTORY   Q                0.5870959     - Perihelion Distance (AU)           
HISTORY   E                0.9672671     - Eccentricity                       
HISTORY   SOMEGA           111.85336     - Arg. of Perihelion (deg)           
HISTORY   LOMEGA            58.15313     - Long. of Ascending Node (deg)      
HISTORY   I                162.23779     - Inclination (deg)                  
                                                                              
     Another HISTORY keyword specifies the antenna rms pointing errors.       
                                                                              
COMMENT             *RMS POINTING ERROR OF TELESCOPE                          
HISTORY   POINTERR  ################ 'UNITS   '                               
                                                                              
     There is a group of keywords to provide information on the calibration   
process.                                                                      
                                                                              
COMMENT             *CALIBRATION METHOD INFORMATION                           
HISTORY   CALMETH   'DESCRIPTION OF CAL METHOD'                               
                                                                              
If the calibration method is unknown, then no line appears.  Current possible 
values are 'CHOPPER WHEEL', 'NOISE TUBE', 'STANDARDS', 'ABSOLUTE'.            
                                                                              
COMMENT             *CALIBRATION STANDARD INFORMATION                         
HISTORY   CALSRCE   'SOURCE NAME'    ########## 'UNITS   '                    
                                                                              
Source (or sources) used to provide principal calibration.  The # field is a  
right justified floating point number. For planets as the calibrators, the    
assumed brightness temperature is given; otherwise, the calibrator flux       
density is given in Jansky.  There may be more than one CALSRCE HISTORY line. 
                                                                              
COMMENT             *SYSTEM TEMPERATURE ETC.                                  
HISTORY   TSYSTEM   ############### '_SB     '                                
HISTORY   TRCVR     ############### '_SB     '                                
                                                                              
Total system temperature (TSYSTEM) and noise temperature of the reciver alone 
(TRCVR).  '_SB     ' allows single side band measurement ('SSB     ') or      
double sideband measurement ('DSB     ') to be indicated.  The # field is a   
right justified floating point number.                                        
                                                                              
HISTORY   TAUZENTH  ###############                                           
                                                                              
Atmospheric opacity at zenith.  The # field is a right justified floating     
point number.                                                                 
                                                                              
     A block of HISTORY lines contains any extra comments about conditions,   
data quality, etc. that are sent to the Discipline Specialist by the observer.
There are generally fewer than eight such comment lines given.                
                                                                              
COMMENT             *OBSERVER COMMENTS                                        
HISTORY   OBSCOMM   ROOM TO REPORT OBSERVER COMMENTS                          
HISTORY   OBSCOMM   ...                                                       
HISTORY   OBSCOMM   ...                                                       
HISTORY   OBSCOMM   MORE ROOM FOR OBSERVER COMMENTS                           
                                                                              
     Comments by the Discipline Specialist team on this observation.  There   
are generally fewer than eight such comment lines given.                      
                                                                              
COMMENT             *DISCIPLINE SPECIALIST COMMENTS                           
HISTORY   DSCOMM    ROOM TO REPORT DISCIPLINE SPECIALIST COMMENTS             
HISTORY   DSCOMM    ...                                                       
HISTORY   DSCOMM    ...                                                       
HISTORY   DSCOMM    MORE ROOM FOR DISCIPLINE SPECIALIST COMMENTS              
                                                                              
                                                                              
                                                                              
Table 6.3.  Keyword Block VI                                                  
                                                                              
______________________________________________________________________________
Keyword  Type  Description                                                    
______________________________________________________________________________
BSCALE    R    Scale factor  data = tape * BSCALE + BZERO                     
BZERO     R    Zero value                                                     
BUNIT     C    Units of data                                                  
               'JY/BEAM ' - for line and continuum data                       
               'STANDARD DEVIATIONS' - for radar data                         
BLANK     I    Value for out-of-range data                                    
CRVALn    R    Value of physical coordinate of nth axis at the reference pixel
CRPIXn    R    Array location of reference pixel for nth axis                 
CDELTn    R    Increment in physical coordinate along nth axis                
CTYPEn    C    Type of physical coordinate                                    
               'VELO-COM' - frequency coordinate for line work in m/s defined 
                            to be velocity relative to the comet              
               'VELO-GEO' - velocity defined relative to center of Earth      
               'FREQUENCY' - frequency offset of radar echo from expected     
                             value in units of Hz                             
               'CIRCULAR POLARIZATION' - axis used to define different states 
                                         of circular polarization: -1 = LHC;  
                                         -2 = RHC                             
               'LINEAR POLARIZATION' - axis used to define linear polarization
                                       position angle                         
               'ECHO POLARIZATION' - axis used to define polarization of radar
                                     echo                                     
               'RAOFF   ' - spatial coordinate for maps (deg)                 
               'DECOFF  ' - spatial coordinate for maps (deg)                 
               'RA      ' - coordinate used for drift scans (deg)             
               'MAP-TYPE' - coordinate to indicate type of drift scan map:    
                            0 = map with comet in beam; 1,2 = maps of galactic
                            background only                                   
CROTAn    R    Rotation angle of physical coordinate axis n                   
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                         7.0. SPECTROSCOPY AND SPECTROPHOTOMETRY              
                                                                              
                                                                              
Table 7.0.  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 SS
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 define
                  as DDCCWWWRQ, where:                                        
                  DD = Detector/Instrument combination.  This is a unique     
                    number for each combination and has been assigned by the  
                    SSN.  The 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 figure below.                        
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 figure below.                             
                                                                              
                                                                              
                                          N                                   
                                  ORIENT  ^                                   
                                       |  |                                   
                                       |  |                                   
                            POSANG     | /|      Tail                         
                               \    N  |/ |     /                             
                  E <---        \   ^  (  *=======                            
                                 \  |   \/ \                                  
                                  \ |   /   Nucleus                           
                                 \ \|  /                                      
                                  \^| /------ SEPNUC                          
                                   \|/                                        
                  Slit Center ------\                                         
                                     \                                        
                                      \---- Slit                              
                                       \                                      
                                                                              
                         Definition of angles.                                
                                                                              
                                                                              
POSANG     F    Position angle of the slit measured north through east,       
                  ranging from 0 to 360 deg.  Two-dimensional spectra only    
                  (figure above).   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 below.                                     
                                                                              
                                                                              
Table 7.2. 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 value
                                        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.             
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                                                                              
                    8.0. AMATEUR OBSERVATIONS                                 
                                                                              
                                                                              
Table 8.0.  Keywords for All Types of Data                                    
                                                                              
______________________________________________________________________________
Keyword                          Description                                  
______________________________________________________________________________
                                                                              
SIMPLE  =                    T / THIS IS A FITS FILE                          
BITPIX  =                    8 / BITS PER PIXEL                               
NAXIS   =                    0 / NO IMAGE DATA ARRAY PRESENT                  
EXTEND  =                    T / THERE MAY BE STANDARD EXTENSIONS             
OBJECT  = 'ooo...oo'           / NAME OF OBJECT                               
FILE-NUM=               8nnnnn / UNIQUE FILE IDENTIFICATION NO.               
DATE-OBS= 'dd/mm/yy'           / DATE OF MIDDLE OF OBSERVATION (UT)           
TIME-OBS=               .ttttt / TIME OF MIDDLE OF OBSERVATION (UT)           
DATE-REL= 'dd/mm/yy'           / DATE OF PUBLIC RELEASE                       
DISCIPLN= 'AMATEUR '           / IHW DISCIPLINE                               
LONG-OBS= 'ddd/mm/ss'          / EAST LONGITUDE OF OBSERVING SITE             
LAT--OBS= 'sdd/mm/ss'          / LATITUDE OF OBSERVING SITE                   
SYSTEM  = '8nnnttii'           / OBSERVING SYSTEM CODE                        
OBSERVER= 'ooo...oo'           / NAME OF OBSERVER                             
SUBMITTR= 'sss...ss'           / NAME OF SUBMITTER OF DATA                    
SPEC-EVT=                    s / SPECIAL EVENT FLAG                           
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                                                                              
Table 8.1.  Keywords for Visual Appearance Descriptions                       
                                                                              
______________________________________________________________________________
Keyword                          Description                                  
______________________________________________________________________________
                                                                              
DAT-FORM= 'ASCII   '           / FORM OF DATA                                 
DAT-TYPE= 'VISUAL MAG. EST.'   / TYPE OF DATA                                 
ELEV-OBS=                 eeee / ELEVATION OF OBSERVING SITE (METER)          
INSTRUME= 'iii...ii'           / TYPE OF INSTRUMENT USED                      
APERTURE=                a.aaa / APERTURE SIZE (METER)                        
FRATIO  =                 ff.f / FOCAL RATIO                                  
POWER   =                  ppp / MAGNIFICATION                                
ORIGIN  = 'JET PROPULSION LAB' / TAPE WRITING INSTITUTION                     
COMMENT ccc...cc                                                              
    :                                                                         
END                                                                           
XTENSION= 'TABLE   '           / TABLE EXTENSION                              
BITPIX  =                    8 / BITS PER PIXEL                               
NAXIS   =                    2 / 2-D MATRIX                                   
NAXIS1  =                   71 / NO. OF CHARACTERS PER ROW                    
NAXIS2  =                    1 / NO. OF ROWS                                  
PCOUNT  =                    0 / NO RANDOM PARAMETERS                         
GCOUNT  =                    1 / ONLY ONE GROUP                               
TFIELDS =                   16 / NO. OF FIELDS PER ROW                        
TTYPE1  = 'MAG. EST. METHOD'   / VALUES: B=BOBROVNIKOFF, M=MORRIS, S=SIDGWICK 
TBCOL1  =                    1 / STARTING COLUMN                              
TFORM1  = 'A1      '           / FORMAT                                       
TNULL1  = '?       '           / MISSING VALUE                                
TTYPE2  = 'COMA MAGNITUDE'     / TOTAL MAGNITUDE    (GIVEN AS ALPHANUMERIC    
TBCOL2  =                    3 / STARTING COLUMN     STRING, SINCE 1ST COL.   
TFORM2  = 'A5      '           / FORMAT              CAN BE > SIGN, WHICH     
TNULL2  = '-99.0   '           / MISSING VALUE       IMPLIES UPPER LIMIT)     
TTYPE3  = 'MAGNITUDE COMMENT'  / INDICATES UNCERTAINTY IF VALUE IS : OR ?     
TBCOL3  =                    8 / STARTING COLUMN                              
TFORM3  = 'A1      '           / FORMAT                                       
TNULL3  = '        '           / MISSING VALUE                                
TTYPE4  = 'CHART NO.'          / USED FOR COMPARISON STARS  (SEE PRINTED CROM-
TBCOL4  =                   10 / STARTING COLUMN             MELIN ARCHIVE OR 
TFORM4  = 'A7      '           / FORMAT                      INT'L. COMET     
                                                             QTRL. FOR EXPLA- 
                                                             NATION)          
TNULL4  = '        '           / MISSING VALUE                                
TTYPE5  = 'COMA DIAMETER 1'    / CIRCULAR COMA DIAM. (OR MAJOR AXIS,          
TBCOL5  =                   18 / STARTING COLUMN      ELLIPTICAL COMA)        
TFORM5  = 'E5.1    '           / FORMAT                                       
TUNIT5  = 'ARCMIN. '           / UNIT                                         
TNULL5  = '-99.0   '           / MISSING VALUE                                
TTYPE6  = 'COMA DIAMETER 2'    / MINOR AXIS, ELLIPTICAL COMA                  
TBCOL6  =                   24 / STARTING COLUMN                              
TFORM6  = 'E5.1    '           / FORMAT                                       
TUNIT6  = 'ARCMIN. '           / UNIT                                         
TNULL6  = '-99.0   '           / MISSING VALUE (OR CIRCULAR COMA)             
TTYPE7  = 'DEGREE OF COND.'    / DEGREE OF CONDENSATION                       
TBCOL7  =                   30 / STARTING COLUMN                              
TFORM7  = 'I1      '           / FORMAT                                       
TNULL7  = '        '           / MISSING VALUE                                
TTYPE8  = 'LENGTH OF TAIL 1'   / TAIL LENGTH (1ST TAIL)                       
TBCOL8  =                   32 / STARTING COLUMN                              
TFORM8  = 'E5.2    '           / FORMAT                                       
TUNIT8  = 'DEGREE  '           / UNIT                                         
TNULL8  = '-9.00   '           / MISSING VALUE                                
TTYPE9  = 'P.A. OF TAIL 1'     / POSITION ANGLE OF TAIL (1ST TAIL)            
TBCOL9  =                   38 / STARTING COLUMN                              
TFORM9  = 'I3      '           / FORMAT                                       
TUNIT9  = 'DEGREE  '           / UNIT                                         
TNULL9  = '-99     '           / MISSING VALUE                                
TTYPE10 = 'LENGTH OF TAIL 2'   / TAIL LENGTH (2ND TAIL, IF SEEN)              
TBCOL10 =                   42 / STARTING COLUMN                              
TFORM10 = 'E5.2    '           / FORMAT                                       
TUNIT10 = 'DEGREE  '           / UNIT                                         
TNULL10 = '-9.00   '           / MISSING VALUE                                
TTYPE11 = 'P.A. OF TAIL 2'     / POSITION ANGLE OF TAIL (2ND TAIL, IF SEEN)   
TBCOL11 =                   48 / STARTING COLUMN                              
TFORM11 = 'I3      '           / FORMAT                                       
TUNIT11 = 'DEGREE  '           / UNIT                                         
TNULL11 = '-99     '           / MISSING VALUE                                
TTYPE12 = 'LENGTH OF TAIL 3'   / TAIL LENGTH (3RD TAIL, IF SEEN)              
TBCOL12 =                   52 / STARTING COLUMN                              
TFORM12 = 'E5.2    '           / FORMAT                                       
TUNIT12 = 'DEGREE  '           / UNIT                                         
TNULL12 = '-9.00   '           / MISSING VALUE                                
TTYPE13 = 'P.A. OF TAIL 3'     / POSITION ANGLE OF TAIL (3RD TAIL, IF SEEN)   
TBCOL13 =                   58 / STARTING COLUMN                              
TFORM13 = 'I3      '           / FORMAT                                       
TUNIT13 = 'DEGREE  '           / UNIT                                         
TNULL13 = '-99     '           / MISSING VALUE                                
TTYPE14 = 'LIMITING MAG.'      / MAGNITUDE OF FAINTEST STAR VISIBLE TO NAKED  
                                  EYE                                         
TBCOL14 =                   62 / STARTING COLUMN                              
TFORM14 = 'E4.1    '           / FORMAT                                       
TNULL14 = '-9.0    '           / MISSING VALUE                                
TTYPE15 = 'SKY INTERFERENCE'   / LIGHT INTERFERING WITH OBSERVATION           
TBCOL15 =                   66 / STARTING COLUMN  (C=CITY LIGHTS, M=MOONLIGHT,
TFORM15 = 'A4      '           / FORMAT            T=TWILIGHT, Z=ZODIACAL     
                                                   LIGHT)                     
TNULL15 = '        '           / MISSING VALUE (NO INTERFERENCE)              
COMMENT VALUE EQUAL TO : IMPLIES UNCERTAINTY IN FAINTEST STAR MAG.            
TTYPE16 = 'DARK ADAPTED'       / WAS OBSERVER DARK ADAPTED? (Y=YES, N=NO)     
TBCOL16 =                   71 / STARTING COLUMN                              
TFORM16 = 'A1      '           / FORMAT                                       
TNULL16 = '        '           / MISSING VALUE                                
END                                                                           
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                                                                              
Table 8.3.  Keywords for Drawings                                             
                                                                              
______________________________________________________________________________
Keyword                          Description                                  
______________________________________________________________________________
                                                                              
DAT-FORM= 'NODATA  '           / FORM OF DATA (NO DATA RECORDS)               
DAT-TYPE= 'DRAWING '           / TYPE OF DATA                                 
ELEV-OBS=                 eeee / ELEVATION OF OBSERVING SITE (METER)          
INSTRUME= 'iii...ii'           / TYPE OF INSTRUMENT USED                      
APERTURE=                a.aaa / APERTURE SIZE (METER)                        
FRATIO  =                 ff.f / FOCAL RATIO                                  
N-POWER =                    n / NO. OF MAGNIFICATIONS USED                   
POWER   =                  ppp / MAGNIFICATION                                
    :                                                                         
MAG-LIM =                  m.m / MAGNITUDE OF FAINTEST STAR VISIBLE TO NAKED  
                                   EYE                                        
PLTSCALE=                ppp.p / PLATE (DRAWING) SCALE (ARCSEC/MM)            
DURATION=                  ddd / TIME FOR MAKING DRAWING (SECOND)             
ORIGIN  = 'JET PROPULSION LAB' / TAPE WRITING INSTITUTION                     
COMMENT ccc...cc                                                              
    :                                                                         
END                                                                           
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                                                                              
Table 8.4.  Keywords for Photographs                                          
                                                                              
______________________________________________________________________________
Keyword                          Description                                  
______________________________________________________________________________
                                                                              
DAT-FORM= 'NODATA  '           / FORM OF DATA (NO DATA RECORDS)               
DAT-TYPE= 'PHOTOGRAPH'         / TYPE OF DATA                                 
ELEV-OBS=                 eeee / ELEVATION OF OBSERVING SITE (METER)          
PRNCPLFL=                p.ppp / PRIMARY, UNMODIFIED INSTR. FOCAL LENGTH      
                                  (METER)                                     
TELEFL  =                t.ttt / EFFECTIVE FOCAL LENGTH (METER)               
APERTURE=                a.aaa / APERTURE SIZE (METER)                        
FRATIO  =                 ff.f / FOCAL RATIO                                  
FOVLENGT=                 ff.f / COMPUTED FOV ASSUMING 135 FORMAT (DEGREE)    
FOVWIDTH=                 ff.f / COMPUTED FOV ASSUMING 135 FORMAT (DEGREE)    
PLTSCALE=                ppp.p / PLATE SCALE (ARCSEC/MM)                      
EMULSION= 'eee...ee'           / TYPE OF EMULSION                             
ISO     = 'aaaa/dd '           / ISO (ASA/DIN)                                
HYPERED = 'hhh...hh'           / HYPERSENSITIZATION TREATMENT                 
TEMP-HYP=                   tt / HYPERSENSITIZATION TEMPERATURE (CELSIUS)     
TIME-HYP=                ttt.t / HYPERSENSITIZATION TIME (HOUR)               
TEMPEMUL=                   tt / COLD CAMERA TEMPERATURE (CELSIUS)            
DEVELOPR= 'ddd...dd'           / DEVELOPER USED                               
TEMP-DEV=                   tt / DEVELOPING TEMPERATURE (CELSIUS)             
TIME-DEV=                  ttt / DEVELOPING TIME (SECOND)                     
GUIDING = 'ggg...gg'           / GUIDING METHOD                               
EXPOSURE=                 eeee / EXPOSURE TIME (SECOND)                       
IM-ID   = 'iii     '           / IMAGE IDENTIFICATION NO.                     
IM-TYPE = 'iii...ii'           / TYPE OF IMAGE ON FILE                        
ORIGIN  = 'JET PROPULSION LAB' / TAPE WRITING INSTITUTION                     
COMMENT ccc...cc                                                              
    :                                                                         
END                                                                           
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                                                                              
Table 8.5.  Keywords for Spectroscopy                                         
                                                                              
______________________________________________________________________________
Keyword                          Description                                  
______________________________________________________________________________
                                                                              
DAT-FORM= 'NODATA  '           / FORM OF DATA (NO DATA RECORDS)               
DAT-TYPE= 'SPECTRUM'           / TYPE OF DATA                                 
ELEV-OBS=                 eeee / ELEVATION OF OBSERVING SITE (METER)          
INSTRUME= 'iii...ii'           / TYPE OF INSTRUMENT USED                      
PRNCPLFL=                p.ppp / PRIMARY, UNMODIFIED INSTR. FOCAL LENGTH      
                                   (METER)                                    
TELEFL  =                t.ttt / EFFECTIVE FOCAL LENGTH (METER)               
APERTURE=                a.aaa / APERTURE SIZE (METER)                        
FRATIO  =                 ff.f / FOCAL RATIO                                  
EMULSION= 'eee...ee'           / TYPE OF EMULSION                             
ISO     = 'aaaa/dd '           / ISO (ASA/DIN)                                
HYPERED = 'hhh...hh'           / HYPERSENSITIZATION TREATMENT                 
TEMP-HYP=                   tt / HYPERSENSITIZATION TEMPERATURE (CELSIUS)     
TIME-HYP=                ttt.t / HYPERSENSITIZATION TIME (HOUR)               
TEMPEMUL=                   tt / COLD CAMERA TEMPERATURE (CELSIUS)            
DEVELOPR= 'ddd...dd'           / DEVELOPER USED                               
TEMP-DEV=                   tt / DEVELOPING TEMPERATURE (CELSIUS)             
TIME-DEV=                  ttt / DEVELOPING TIME (SECOND)                     
GUIDING = 'ggg...gg'           / GUIDING METHOD                               
EXPOSURE=                 eeee / EXPOSURE TIME (SECOND)                       
GRATING =                ggg.g / GRATING CONSTANT (METER)                     
ORDER   =                    o / BLAZE ORDER                                  
APDSPRSR=               a.aaaa / DISPERSER APERTURE (METER)                   
PROJDIST=               p.pppp / PROJECTION DISTANCE (METER)                  
APEX-ANG=                  aaa / PRISM APEX ANGLE (DEGREE)                    
GLASSTYP= 'ggg...gg'           / PRISM GLASS TYPE                             
AP-PRISM=               a.aaaa / PRISM APERTURE (METER)                       
METHOD  = 'mmm...mm'           / SPECTROSCOPIC METHOD                         
IM-ID   = 'iii     '           / IMAGE IDENTIFICATION NO.                     
IM-TYPE = 'iii...ii'           / TYPE OF IMAGE ON FILE                        
ORIGIN  = 'JET PROPULSION LAB' / TAPE WRITING INSTITUTION                     
COMMENT ccc...cc                                                              
    :                                                                         
END                                                                           
______________________________________________________________________________
                                                                              
                                                                              
                                                                              
                                                                              
                           9.0. METEOR STUDIES NETWORK                        
                                                                              
                                                                              
Table 9.1.  Main Header                                                       
                                                                              
__________________________________________________________________________    
KEYWORD              EXPLANATION                FORMAT                        
__________________________________________________________________________    
BITPIX   =               8 \ 8-bit characters                                 
EXTEND   =               T \ Yes, a table                                     
DAT-FORM = 'ASCII  '                                                          
OBJECT     Name of meteor shower                'ORIONID' or 'ETA-AQUARID'    
FILE NUM = File number--Beginning with 9 and                                  
           followed by a unique 5-digit num-                                  
           ber                                                                
DATE-OBS   UT date of middle of observing pe-                                 
           riod. See notes for shower periods   'DD/MM/YY'                    
TIME-OBS   UT time of middle of observation.                                  
           Not significant for meteor observa-                                
           tions and therefore usually given                                  
           as 0.0                                                             
DISCIPLN   IHW Discipline                       'METEOR STUDIES'              
SYSTEM     Key to finding observing system in                                 
           discipline/station catalog. Insti-                                 
           tutes with long-standing observing                                 
           instruments are listed in Attach-                                  
           ment C                               '9uuuccnn'                    
OBSERVER   'Onename,I'                                                        
   or          or                                                             
SUBMITTR   'Oneperson,J/Otherperson,K'                                        
               or                                                             
           'Firstperson,L/ET AL' if more than                                 
           two                                                                
DAT-FORM   'ASCII    ' data are in character                                  
           form, usually implying tables and                                  
           BITPIX=8.                                                          
OBSVTORY   name of submitting observatory       'Tadjik Astrophy Inst'        
LOCATION   location of submitting observatory   'Dushanbe, USSR'              
LIM-SENS   threshold sensitivity for obser-                                   
           vations not cataloged by SYSTEM.                                   
           Given as limiting magnitude (pho-                                  
           tographic, visual, or equivalent                                   
           radio magnitude or electron line     '+8M radio'                   
           density)                             '10**14 electron/m'           
QUALITY    estimate of the quality of the ob-                                 
           servation on a scale of: 1 = poor,                                 
           to 5 = excellent, with 0 = unknown   2                             
__________________________________________________________________________    
                                                                              
                                                                              
                                                                              
                                                                              
Table 9.2.  Example of EXTENSION Header and Data for Radar Observations       
                                                                              
___________________________________________________________________________   
                                                                              
XTENSION= 'TABLE   '            / table extension                             
BITPIX  =                    8  / bits per character                          
NAXIS   =                    2  / dimensions of table                         
NAXIS1  =                  100  / characters per line                         
NAXIS2  =                  193  / hours of observations                       
PCOUNT  =                    0  / no random parameters                        
GCOUNT  =                    1  / only one group                              
TFIELDS =                   35  / fields per line                             
EXTNAME = 'ORIONIDS 86'         / name of table                               
COMMENT   Description of the table columns.                                   
COMMENT   There is one space between each field.                              
TTYPE1  = 'YR      '            / year                                        
TBCOL1  =                    1  / starting column                             
TFORM1  = 'I2      '            / 2-digit integer                             
TTYPE2  = 'MO      '            / month                                       
TBCOL2  =                    4  / starting column                             
TFORM2  = 'I2      '            / 2-digit integer                             
TTYPE3  = 'DA      '            / UT day                                      
TBCOL3  =                    7  / starting column                             
TFORM3  = 'I2      '            / 2-digit integer                             
TTYPE4  = 'HR      '            / UT hour                                     
TBCOL4  =                   10  / starting column                             
TFORM4  = 'I2      '            / 2-digit integer                             
TTYPE5  = 'TOTAL   '            / total hour count                            
TBCOL5  =                   13  / starting column                             
TFORM5  = 'I3      '            / 3-digit integer                             
TTYPE6  = '>=1sec  '            / count for durations >=1 sec                 
TBCOL6  =                   17  / starting column                             
TFORM6  = 'I3      '            / 3-digit integer                             
TTYPE7  = '>=8sec  '            / count for durations >=8 sec                 
TBCOL7  =                   21  / starting column                             
TFORM7  = 'I2      '            / 2-digit integer                             
TTYPE8  = ' 75     '            / count in 10km range class 70-80 km          
TBCOL8  =                   24  / starting column                             
TFORM8  = 'I1      '            / 1-digit integer                             
TTYPE9  = ' 85     '            / count in 10km range class                   
TBCOL9  =                   26  / starting column                             
TFORM9  = 'I2      '            / 2-digit integer                             
TTYPE10 = ' 95     '            / count in 10km range class                   
TBCOL10 =                   29  / starting column                             
TFORM10 = 'I2      '            / 2-digit integer                             
TTYPE11 = '105     '            / count in 10km range class                   
TBCOL11 =                   32  / starting column                             
TFORM11 = 'I2      '            / 2-digit integer                             
TTYPE12 = '115     '            / count in 10km range class                   
TBCOL12 =                   35  / starting column                             
TFORM12 = 'I2      '            / 2-digit integer                             
TTYPE13 = '125     '            / count in 10km range class                   
TBCOL13 =                   38  / starting column                             
TFORM13 = 'I2      '            / 2-digit integer                             
TTYPE14 = '135     '            / count in 10km range class                   
TBCOL14 =                   41  / starting column                             
TFORM14 = 'I2      '            / 2-digit integer                             
TTYPE15 = '145     '            / count in 10km range class                   
TBCOL15 =                   44  / starting column                             
TFORM15 = 'I2      '            / 2-digit integer                             
TTYPE16 = '155     '            / count in 10km range class                   
TBCOL16 =                   47  / starting column                             
TFORM16 = 'I2      '            / 2-digit integer                             
TTYPE17 = '165     '            / count in 10km range class                   
TBCOL17 =                   50  / starting column                             
TFORM17 = 'I2      '            / 2-digit integer                             
TTYPE18 = '175     '            / count in 10km range class                   
TBCOL18 =                   53  / starting column                             
TFORM18 = 'I2      '            / 2-digit integer                             
TTYPE19 = '185     '            / count in 10km range class                   
TBCOL19 =                   56  / starting column                             
TFORM19 = 'I2      '            / 2-digit integer                             
TTYPE20 = '195     '            / count in 10km range class                   
TBCOL20 =                   59  / starting column                             
TFORM20 = 'I2      '            / 2-digit integer                             
TTYPE21 = '205     '            / count in 10km range class                   
TBCOL21 =                   62  / starting column                             
TFORM21 = 'I2      '            / 2-digit integer                             
TTYPE22 = '215     '            / count in 10km range class                   
TBCOL22 =                   65  / starting column                             
TFORM22 = 'I2      '            / 2-digit integer                             
TTYPE23 = '225     '            / count in 10km range class                   
TBCOL23 =                   68  / starting column                             
TFORM23 = 'I2      '            / 2-digit integer                             
TTYPE24 = '235     '            / count in 10km range class                   
TBCOL24 =                   71  / starting column                             
TFORM24 = 'I2      '            / 2-digit integer                             
TTYPE25 = '245     '            / count in 10km range class                   
TBCOL25 =                   74  / starting column                             
TFORM25 = 'I2      '            / 2-digit integer                             
TTYPE26 = '255     '            / count in 10km range class                   
TBCOL26 =                   77  / starting column                             
TFORM26 = 'I2      '            / 2-digit integer                             
TTYPE27 = '265     '            / count in 10km range class                   
TBCOL27 =                   80  / starting column                             
TFORM27 = 'I2      '            / 2-digit integer                             
TTYPE28 = '275     '            / count in 10km range class                   
TBCOL28 =                   83  / starting column                             
TFORM28 = 'I2      '            / 2-digit integer                             
TTYPE29 = '285     '            / count in 10km range class                   
TBCOL29 =                   86  / starting column                             
TFORM29 = 'I2      '            / 2-digit integer                             
TTYPE30 = '295     '            / count in 10km range class                   
TBCOL30 =                   89  / starting column                             
TFORM30 = 'I2      '            / 2-digit integer                             
TTYPE31 = '305     '            / count in 10km range class                   
TBCOL31 =                   92  / starting column                             
TFORM31 = 'I1      '            / 1-digit integer                             
TTYPE32 = '315     '            / count in 10km range class                   
TBCOL32 =                   94  / starting column                             
TFORM32 = 'I1      '            / 1-digit integer                             
TTYPE33 = '325     '            / count in 10km range class                   
TBCOL33 =                   96  / starting column                             
TFORM33 = 'I1      '            / 1-digit integer                             
TTYPE34 = '335     '            / count in 10km range class                   
TBCOL34 =                   98  / starting column                             
TFORM34 = 'I1      '            / 1-digit integer                             
TTYPE35 = '345     '            / count in 10km range class                   
TBCOL35 =                  100  / starting column                             
TFORM35 = 'I1      '            / 1-digit integer                             
END                                                                           
__________________________________________________________________________    
                                                                              
                                                                              
                                                                              
                                                                              
Table 9.3.  Example of EXTENSION Header and Data for Visual Observations      
                                                                              
__________________________________________________________________________    
                                                                              
XTENSION= 'TABLE   '            / table extension                             
BITPIX  =                    8  / bits per character                          
NAXIS   =                    2  / dimensions of table                         
NAXIS1  =                   40  / characters per line                         
NAXIS2  =                  134  / number of lines in the table                
PCOUNT  =                    0  / no random parameters                        
GCOUNT  =                    1  / only one group                              
TFIELDS =                   10  / fields per line                             
EXTNAME = 'ETA-AQUARIDS85'      / name of table                               
COMMENT   Description of the table columns.                                   
TTYPE1  = 'YR      '            / year                                        
TBCOL1  =                    3  / starting column                             
TFORM1  = 'I2      '            / 2-digit integer                             
TTYPE2  = 'MO      '            / month                                       
TBCOL2  =                    6  / starting column                             
TFORM2  = 'I2      '            / 2-digit integer                             
TTYPE3  = 'DAY     '            / UT day & fraction                           
TBCOL3  =                   10  / starting column                             
TFORM3  = 'E5.2 '               / 5-DIGIT 2 DECIMAL PLACES                    
TTYPE4  = 'TIME    '            / total minute count                          
TBCOL4  =                   16  / starting column                             
TFORM4  = 'I3                   / 3-digit integer                             
TTYPE5  = 'OBS     '            / observer number                             
TBCOL5  =                   20  / starting column                             
TFORM5  = 'I3      '            / 3-digit integer                             
TTYPE6  = 'SITE    '            / site number                                 
TBCOL6  =                   24  / starting column                             
TFORM6  = 'I3      '            / 3-digit integer                             
TTYPE7  = 'F-STAR  '            / faintest magnitude visible                  
TBCOL7  =                   29  / starting column                             
TFORM7  = 'E3.1    '            / 3-digit 1 decimal place                     
TTYPE8  = 'CLOUD   '            / cloud cover in %                            
TBCOL8  =                   33  / starting column                             
TFORM8  = 'I2      '            / 2-digit integer                             
TTYPE9  = 'NUM-SH  '            / count shower meteors                        
TBCOL9  =                   35  / starting column                             
TFORM9  = 'I3      '            / 3-digit integer                             
TTYPE10 = 'NUM-NS  '            / count non-shower meteors                    
TBCOL10 =                   38  / starting column                             
TFORM10 = 'I3      '            / 3-digit integer                             
END                                                                           
______________________________________________________________________________