PRO vis_fwdfit_pso_src_structure__define
  ;
  ; Defines a structure that defines one component of a source structure used by hsi_vis_fwdfit and related modules.
  ;
  ; {hsi_vis_source_structure} returns the following structure

  dummy = {vis_fwdfit_pso_src_structure,   $
    srctype:      ' ',      $   ; Label indicating source type
    srcflux:       0.,      $   ; Semi-calibrated flux (ph/cm2/s)
    srcx:          0.,      $   ; X-offset (+W) relative to sun center (arcsec)
    srcy:          0.,      $   ; Y-offset (+N) relative to sun center (arcsec)
    srcfwhm_max:   0.,      $   ; Source FWHM diameter (arcsec)
    srcfwhm_min:   0.,      $   ; Source FWHM diameter (arcsec)
    eccen:         0.,      $   ; Eccentricity of elliptical source
    srcpa:         0.,      $   ; Position angle of long axis (degrees E of N)
    loop_angle:    0.}          ; Angle subtended by loop, as seen from its center of curvature (deg)
  RETURN
END