def fits_file_name(rerun, run, camcol, field, band):
    """
    SDSS FITS files are named, e.g., 'frame-g-001000-1-0027.fits.bz2'.
    We will uncompress this and save it as 'frame-g-001000-1-0027.fits'.

    This function returns 'frame-g-001000-1-0027.fits' in this case
    (without the '.bz2' extension).
    """

    return "frame-{4}-{1:06d}-{2}-{3:04d}.fits".format(
        rerun, run, camcol, field, band
    )