See: /home/sco/Installs/install_sco2019_20190511/codes/python/fits_files/README.splitfits https://gist.github.com/vterron/24d904f4711006b07997 % python splitfits.py 20190323T012645.5_gc2_sci.fits test2.fits 1 After install with pyput: % splitfits.py 20190711T040955.1_gc1_sci.fits t1.fist 1 **** NOTE: This grabs only the extension image. In ds9: # load multiple extension fits file as multiple frames % ds9 -multiframe 20190711T040955.1_gc1_sci.fits