AIPS HELP file for COORDINA in 31DEC25

As of Wed Apr 2 0:23:43 2025

HELP SECTION

COORDINA
Type: Adverb   (Real(6))
Use:  An array adverb used to convey coordinate values as:
         Xpos = abs(COOR(1)) + abs(COOR(2))/60 + abs(COOR(3))/3600
            if any of COOR(1), COOR(2), COOR(3) < 0: Xpos = -Xpos
         Ypos = abs(COOR(4)) + abs(COOR(5))/60 + abs(COOR(6))/3600
            if any of COOR(4), COOR(5), COOR(6) < 0: Ypos = -Ypos
      Note that, although these are most suited to RA, Dec in
      sexagesimal notation, they can be used for any type of coordinate.
      The units are standard units of the X and Y axes (e.g degrees,
      m/sec, Hz, sec, etc.) except that right ascensions are in hours of
      time.

      It is normal in print to represent a declination between -1 and
      0 degrees as -0d mm ss.s.  But if you type, e.g.
          COORDINA = 14, 8, 23.3, -0, 14, 23
      you will get a positive declination because there is no
      difference numerically between -0 and +0.  You need to type
          COORDINA = 14, 8, 23.3, -0, -14, 23
      to get the desired negative coordinate.  BE VERY CAREFUL when
      you type negative coordinates to use commas to separate the
      values.  Otherwise the minus sign becomes a subtraction sign and
      you do not get the desired values in the adverb.

Null value:  None, 0 means 0.

Verbs:
  CODECIML....Convert between decimal and sexagesimal coordinate
              values
  COODEFIN....Define or modify an image axis coordinate description
  COPIXEL.....Convert between physical and pixel coordinate values
  COSTAR......Plot a symbol on the TV at the specified coordinate.
  COTVLOD.....Load a TV image centered on the specified coordinate.
  COWINDOW....Set BLC, TRC centered on a coordinate.
  EPOCONV.....Convert between J2000 and B1950 coordinates
  IMCENTER....Returns pixel position of sub-image centroid
  IMPOS.......Displays celestial coordinates selected by the TV cursor
  IMVAL.......Returns image intensity and coordinate at specified
              pixel
  MAXFIT......Returns pixel position and image intensity at a maximum
  QIMVAL......Returns image intensity and coordinate at specified
              pixel quietly

Build-in procedures:
  TVFLUX......Displays coordinates and values selected with the TV
              cursor
  TVMAXFIT....Displays fit pixel positions and intensity at maxima on
              TV

Tasks:
  CHKFC.......Makes images of Clean boxes from Boxfile.  COORDINA sets
              the center coordinate when the BOXFILE contains boxes
              defined as shifts.
  FLATN.......Re-grid multiple fields into one image incl sensitivity
              COORDINA selects the output central coordinate.
  MODAB.......Makes simple absorption/emission spectral-line image in
              I/V.  COORDINA defines the central RA/Dec coordinate.
  MODIM.......Adds images of model objects to image cubes in IQU
              polarization.  COORDINA defines the central RA/Dec when
              making a brand new image.
  MODSP.......Adds images of model objects to image cubes in I/V
              polarization.   COORDINA defines the central RA/Dec when
              making a brand new image.
  PBCOR.......Task to apply or correct an image for a primary beam.
              COORDINA provides the pointing center if necessary
  SDVEL.......Shifts spectral-line single-dish data to a given
              velocity.  COORDINA provides the coordinate to be used
              for the velocity reference.
  SPCOR.......Task to correct an image for a primary beam and spectral
              index.  COORDINA provides the pointing center if
              necessary.
  SPXMD.......Adds images of model objects to image cubes in spectral
              index.
  SUFIX.......Modifies source numbers on uv data.  COORDINA provides
              the coordinates of a new source.

EXPLAIN SECTION