Importfits
From CASA Guides
Help on importfits task:
Convert an image FITS file into a CASA image Standard image FITS files are processed into a Casa image Keyword arguments: fitsimage -- Name of input image FITS file default: none; example='3C273XC1.fits' imagename -- Name of output CASA image default: none; example: imagename='3C273XC1.image' whichrep -- If fits image has multiple coordinate reps, choose one. default: 0 means first; example: whichrep=1 whichhdu -- If fits file contains multiple images, choose this one default=0 mean first; example: whichhdu=1 zeroblanks -- Set blanked pixels to zero (not NaN) default=True; example: zeroblanks=True overwrite -- Overwrite pre-existing imagename default=False; example: overwrite=True