CFHT Science Archive

CFHT Science Archive CFHT File Extensions

CFHT File Extensions

For more details, please visit the CFHT instrumentation pages.

All instruments

  • o: A RAW CFHT exposure


  • p: Elixir processed observation
  • b: bias/zero frame
  • f: flat field exposure
  • d: dark


  • p: `I`iwi processed image
  • s: `I`iwi processed image without sky background subtraction
  • g: time-series data cubes containing image cutouts from the WIRCAM guider boxes
  • w: weight maps
  • m: mask file (a composite of several masks computed for each exposure including the guide-windows)
  • y: sky construct (ie: what was removed from a sky-subtracted image)
  • a: acquire (short image to acquire the correct field)
  • d: dark
  • f: flat field


  • p: polarization spectra (the combination of four individual exposures)
  • i: individual intensity spectra
  • n: continuum normalized to 1
  • u: continuum not normalized
  • a: align exposure (to line up target and fibre)
  • b: bias/zero
  • c: comparison lamp
  • f: flat field
  • x: focus sequence