Added automatic name in the form RAW.telescop_keyword.time_stamp.fits

        hdul = fits.HDUList([noche_hdu, original_hdu])

        if overwrite:

            log.warning(f"Overwrite enabled")

        if not filename:

            prefix = "RAW"

            tel = self.noche.header["TELESCOP"].replace(" ","_").upper()

            timestamp = self.noche.header["DATE-OBS"].replace(":","_")

            filename = self.output_dir / f"{prefix}.{tel}.{timestamp}.fits"

            log.warning(f"No filename provided, using {filename}")

            tel = self.header["TELESCOP"].replace(" ","_").upper()

            timestamp = self.header["DATE-OBS"].replace(":","_")

            filename = f"{prefix}.{tel}.{timestamp}.fits"

            log.warning(f"No filename provided, using default")

        log.info(f"Saving as {filename}")

        hdul.writeto(filename,

                      overwrite=overwrite, checksum=True)

                    pass

        return val