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1696 lines***** 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
______________________________________________________________________________