
1 ASTROMETRIC
        ASTROMETRIC [RAmin RAmax DECmin DECmax]  [/MAGNITUDE  Mlim]  [/EPOCH
    date] [/OUTPUT File] [/EQUINOX date]

    Searches and plots all astrometric stars of  magnitude  less  than  Mlim
    (brighter than Mlim) in the (RA,DEC) box specified by RAmin RAmax DECmin
    DECmax (if present; otherwise, in the current Greg box provided that the
    coordinate  system  is  equatorial). The current marker type is used and
    the size depends on the current marker size and on the star magnitude.

    Proper motions are included to represent the sky at the  date  specified
    in the /EPOCH option if present, at the current day otherwise.

    The stars are precessed to the equinox specified by option  /EQUINOX  if
    present, and otherwise to the equinox defined in variable G_EPOCH.

    If option /OUTPUT is present, star positions, magnitudes, spectral types
    and  names  are  written  in  the specified file (which defaults to user
    terminal).

    NOTES:
      - Palomar/SRC Survey Schmidt Plates (POSS#I) are squares of size 35.56
        cm (14 inches) with a scale of 67.14 Arcsec. per mm.
      - ESO Survey Plates are squares of size 30 cm with  a  scale  of  67.6
        Arcsec. per mm.
    If you want to make overlays, do not forget the /EXACT option in command
    HARDCOPY/PLOT ...
1 GSC
        GSC [RAmin RAmax DECmin  DECmax]  [/MAGNITUDE  Mlim]  [/EPOCH  date]
    [/OUTPUT File Ident] [/MERGE]

    Search and plots all stars in the Guide Star Catalog with magnitude less
    than  Mlim  (brighter  than Mlim) in the (RA,DEC) box specified by RAmin
    RAmax DECmin DECmax (if present, and in the current Greg box  otherwise,
    provided that the coordinate system is equatorial). Please note that the
    very brightest stars (V<6) have only been added at version 1.1 and  will
    be  missing  if  you  are  using  GSC  version  1.0. Most of them can be
    obtained by using the ASTROM command.  The current marker type  is  used
    and  the  size  depends  on  the  current  marker  size  and on the star
    magnitude.

    No proper motion is applied as this  information  is  not  available  in
    versions  1.x  of  the  GSC  catalog. The /EPOCH option is therefore not
    used.

    If option /EQUINOX is present, the stars are precessed to the equinox it
    specifies.  They  are  otherwise precessed to the equinox of the map, as
    defined in variable G_EPOCH.

    If option /OUTPUT is present, star positions and magnitudes  with  their
    error  estimates,  are  written in the specified file (which defaults to
    user  terminal),  together  with  some  ancillary  Guide  Star   Catalog
    information (original plate, multiplicity flag,...). The presence of the
    second argument, Ident, will generate an identification number for  each
    star  in  the output file, and plot this number near the star's position
    on the graphic display. Useful for identification purposes. The list  of
    information stored in the file is located under subtopic Format

    If  option  /MERGE  is  present,  multiple  detections  of  objects   on
    overlapping  plates are merged (by simple averaging). Individual entries
    are otherwise plotted and listed.

    NOTES:
      - Palomar/SRC Survey Schmidt Plates (POSS#I) are squares of size 35.56
        cm (14 inches) with a scale of 67.14 Arcsec. per mm.
      - ESO Survey Plates are squares of size 30 cm with  a  scale  of  67.6
        Arcsec. per mm.
    If you want to make overlays, do not forget the /EXACT option in command
    HARDCOPY/PLOT ...
2 FORMAT
        Format            of            table            lines            is
    ([i4],I5,F9.5,F9.5,F5.1,F5.2,F4.2,I2,I1,A4,A1) for
    * [optional star Ident number]
    * ID  within region
    * RA (degrees)
    * DEC (degrees)
    * Position error (arc seconds)
    * Magnitude
    * Magnitude error
    * Magnitude band
    * Classification
    * Plate ID
    * Multiplicity flag
1 HEADER
        HEADER [Image_Name] /EXTREMA

    Compute the extrema of the current or specified image,  and  update  the
    header accordingly.

        HEADER /UPDATE

    Update the header of the current image, for example after  modifications
    to the G_* header variables have been made. The header variables are
    G_NDIM         Number of dimensions
    G_DIM[4]       Image dimensions
    G_CONVERT[3,4] Conversion formula (Ref, Val, Inc for each axis)
    G_BLANK[2]     Blanking and tolerance
    G_MAX          Maximum value
    G_MIN          Minimum value
    G_EXTREMA      Zero (0) if no extrema defined
    G_WHERE[2,4]   Pixel of maximum and minimum
    G_UNITi        Units of axis i
    G_UNIT         Units of map
    G_COORD        System coordinates
    G_SOURCE       Source name
    G_EPOCH        Epoch of coordinates
    G_RA           Right Ascension (of Object)
    G_DEC          Declination (of Object)
    G_LII          Galactic longitude (of Object)
    G_BII          Galactic latitude (of Object)
    G_PTYP          Projection Type (0:none,1:Gnomonic,2:Orthographic,
                    3:Azimuthal,4:Stereographic,5:Lambert,6:Aitoff,7:Radio).
                    Warning: these codes are subject to change without notice.
    G_XAXI         The first axis of projection (1,2,3 or 4)
    G_YAXI         The second axis of projection (1,2,3 or 4)
    G_A0           Position of projection center for axis G_XAXI (R.A. or LII)
    G_D0           Position of projection center for axis G_YAXI (DEC. or BII)
    G_ANGLE        Angle of projection (East of North)
    G_LINE         Line name
    G_FREQRES      Frequency resolution
    G_RESTFRE      Signal rest frequency
    G_FREQOFF      Image rest frequency
    G_VELRES       Velocity resolution
    G_VELOFF       Velocity of reference channel
    G_PA           Position angle of beam
    G_MINOR        Minor axis size of beam
    G_MAJOR        Major axis size of beam
    G_BEAM         Size of RESOLUTION section (0 or 3)

        HEADER [Image_Name] [/OUTPUT FIle_Name]

    Give the Header of the current or specified Image, on the screen  or  in
    the  specified output file.  Provided you have write access to the image
    and nobody else is already using it, the header may be  editted  if  the
    terminal  is  a  VT100 compatible. The keys of the VT100 keypad have the
    same meaning as in EDT:
               +--------+--------+--------+--------+
               |  enter |        |        |  Del L |
               |  edit  |        |        |        |
               +--------+--------+--------+--------+
               |  print |        |        |  Del W |
               |  header|        |        |        |
               +--------+--------+--------+--------+
               | Advance| Backup |        |  Del C |
               |        |        |        |        |
               +--------+--------+--------+--------+
               |  Word  |   Eol  |  Char  |        |
               |        |        |        |  Enter |
               +--------+--------+--------+        |
               |       Line      |        |(Update)|
               |                 |        |        |
               +-----------------+--------+--------+
     To edit a field, press the GOLD (PF1) key.
     To compute MAXIMA and MINIMA of current image, strike ENTER key.
     Strike <^Z> to exit.
     The header will be automatically updated if any modification  has  been
    made.
1 IMAGE
        IMAGE [Filename] [/PLANE  I1  I2]  [/SUBSET  Imin  Imax  Jmin  Jmax]
    [/WRITE]

    Read the GDF map Filename. The default  image  extension  is  .GDF  This
    command  defines the image found in given file as the new current image.
    Projection, system and extremas  are  also  defined  if  needed.  Unless
    options  are  present,  the  first  plane  of  the image becomes the new
    Regular Grid array in GreG.

    The /PLANE I1 I2 option  allows  to  define  part  of  a  more  than  2-
    Dimensional  image  as the regular grid array. A file name should not be
    specified if you want to select a new plane in the current image.

    The /SUBSET Imin Imax Jmin Jmax option allows to load only a  subset  of
    the  input  image or image plane. Again, a file name should be specified
    only to change the input image.

    The /WRITE option allows you to map  the  image  writeable  (instead  of
    Readonly  by  default),  a prerequisite to use some functions (e.g. KILL
    which kills pixels). The mapped image is  then  non-shareable  by  other
    users...

    You can combine /PLANE and /SUBSET options.
1 IRAS
        IRAS Band [Ramin  Ramax  Decmin  Decmax]  [/FLUX  Threshold]  [/SIZE
    Flux_value]

    Plots a marker at the position of all IRAS  point  sources  detected  at
    band  Band (specified by its wavelength in microns 12, 25, 60 or 100) in
    the area  defined  by  Ramin,  Ramax  (in  hours),  Decmin,  Decmax  (in
    degrees). If the option /FLUX is given, only sources with a flux greater
    than Threshold will be select. If the option /SIZE is given, the  marker
    size  will  be proportional to the logarithm of the flux (sources with a
    flux equal to Flux_value having the current marker size as specified  by
    SET MARKER command). The current marker type is used.

    Command IRAS completely ignores the current GreG box to select the  IRAS
    point sources, but the markers will be clipped in this box when plotted.
    Hence, it is up to the user to ensure that the system is EQUATORIAL  and
    that  the  projection  area (specified by command LIMITS and PROJECTION)
    reasonably matches the selection area specified in command IRAS.
1 KILL
        KILL

    KILL calls the interactive cursor. Recognised keys are:
      - V to give the value of the pixel
      - K to give the current blanking value to the pixel
      - I to interpolate the value from the neighbour pixels.
      - E to exit from interactive cursor mode
    Any other key is ignored.
1 Language
        GRAPHIC\ Language Summary
    ASTROMETRIC     : Plots astrometric star positions (for finding charts)
    HEADER          : Give the Header of the current Image.
    IMAGE [Filename]: Read the GDF map Filename. Default extension is .GDF
    IRAS Band       : Select and plot IRAS sources of a given band
    KILL            : Kills pixels.
    PSC_IRAS        : Get characteristics of IRAS point source
    REGRESSION [Val]: Computes regression lines
    SPECTRUM        : Extract a spectrum from an image (to plot it).

1 PSC_IRAS
        [ALL\]PSC_IRAS [Ra. Dec.] [/OUTPUT Filename] [/LOOK Around]

    Find  IRAS  characteristics  of  point  sources  around  the   specified
    position.  If no position is given, it calls the interactive cursor, and
    uses the returned coordinates to look for all IRAS sources  around  this
    point.  The  value  Around (argument of option /LOOK) is the size of the
    search area in arc minutes (default 1). The result depends  whether  the
    full compact catalog is on line or not.
      - If not, the fluxes of the sources found in the search box are  typed
        on the screen.
      - If it is on line, full information about the sources is either typed
        on  the  screen,  or  written  on the file specified by the argument
        Filename of option /OUTPUT.
    In addition,  a  binary  output  file  (whose  name  is  PSCSUB.TAB)  is
    produced.   This binary file is suited for later processing by the Point
    Source Catalog software. The same files (formatted and binary) are  used
    for  multiple  use  of  this command (unless the Filename is explicitely
    changed).

2 FORMAT

    The listing produced by PSC_IRAS or the IRAS command has  the  following
    format :

    Right Ascension         Sexagesimal notation in Hours
    Declination             Sexagesimal notation in Degrees
    Lii                     (Degrees)
    Bii                     (Degrees)
    Semi-Major axis of position uncertainty ellipsis  (  Arc Seconds
    Semi-Minor axis of position uncertainty ellipsis   95 confidence)
    Position Angle of the uncertainty ellipsis. (Degrees from North)
    Number of Hour confirmations
    Number of LRS spectra
    Type of LRS spectra
    Variability flag
    Discrepant flux flag
    Confusion flux flag
    Number of nearby hour confirmed point sources
    Number of nearby week confirmed point sources
    High source density bin flag
    CIRR1   Cirrus flag 1
    CIRR2   Cirrus flag 2
    CIRR3   100 micron sky brightness (MJy/Sr)
    Number of identifications
    Type of identifications

    For each flux (12, 25, 60 100 microns)
            Flux    (Jy)
            Flux quality (1 upper limit, 2 poor, 3 good)
            Calibration uncertainty (%)
            Signal to noise ratio multiplied by 10
            Point source correlation coefficient
            Number of hour confirmed small extended sources
            Number of week confirmed small extended sources

    Identifications (one line per identification)
            Name
            Catalog dependant informations
            Catalog name
1 REGRESSION
        REGRESSION Nmin [/RANGE [X Xmin Xmax] [Y Ymin Ymax]]

    Computes linear regressions in a image which is the correlation  of  two
    coincident images. The regression lines
           Y = A * X + B   and    X = A'* Y + B'
    are computed assuming the weight of any (X,Y) is the value of the  pixel
    at  X,Y. Nmin is the minimum pixel value considered as significant.

1 SPECTRUM
        SPECTRUM I [J [K]]

    Extract a spectrum from an image according to the following numbering :
        Spectrum (l) = Image (l,i,j,k)
    for a 4-dimensional image. The spectrum is loaded into the  X,Y  buffers
    of  GreG.  It  can  be  processed later by the standard commands LIMITS,
    CONNECT, CURVE and so on.

































