fitstopnm
Convert a Flexible Image Transport System (FITS) file to a PNM image.
TLDR
Convert a FITS file to a PNM image
$ fitstopnm [path/to/file.fits] > [path/to/output.pnm]
Convert the image on the specified position of the third axis in the FITS file
$ fitstopnm -image [z_position] [path/to/file.fits] > [path/to/output.pnm]
