next up previous contents
Next: *wcscoord* all Up: Celestial Coordinates from Image Previous: *tvlabel, xexamine*

*skypix* -- conversion of pixel position to sky coordinates

To convert from pixels to RA and Dec. first view image with SAOimage. Set cursor on object of interest. Read pixel coord from SAOimage (coord must be on). Run skypix in separate window. Type pixel coords in skypix.

  xr> xspatial
  xs> skypix.oformat = ``hours''  # to reset the default which is ``degrees''.
  xs> skypix

  input coordinate system (J2000): xdata$rh110267_img    # the image file name 
  output coordinate system (J2000): image            # to use coord conversion
                                                        # in image file header
  or B1950 or J2000                         # epoch of output can be specified
  input file list (STDIN): <cr>

...conversion explained, note epoch of output...

  145  276<cr>                                    # pixels read from SAOimage
        22:08:41.6  45:44:38.0                                  # RA and dec.
  256  265<cr> 
        22:07:16.8  45:42:00.0
  ctrl d                                                            # to quit