timedelta

                    self.error.append(msg)

                    return

                else:

                    elapsed = (Time.now() - now).sec

                    elapsed = (Time.now() - now).sec.item()

                    msg = f"Camera {

                        camera_state[status]}, {

                        elapsed:.1f}/{exptime}s "

            log.debug(f"Downloading... (cam state {image_state[cam.ready]})")

            cam.download()

            log.info(f"Elapsed {(Time.now() - now).sec:.2f}")

            log.info(f"Elapsed {(Time.now() - now).sec.item():.2f}")

            ##################################

            ##### Update header and save #####

    # If current UTC hour is before midday UTC, the "observing night"

    # belongs to the previous calendar date.

    if now.datetime.hour < 12:

        folder_date_obj = now.datetime.date() - timedelta(days=1)

        folder_date_obj = now.datetime.date() - datetime.timedelta(days=1)

    else:

        folder_date_obj = now.datetime.date()

    return folder_date_obj.strftime("%Y-%m-%d")

    # '2021-12-28T20:09:56.163'

    date_obs_str = header[dateobs]  # DATE-OBS from FITS header

    name_for_file = Time(date_obs_str).isot

    outfile_name = f"{FILE_PREFIX}.{name_for_file}.{FITS_EXT}"

    outfile = Path(outfile_name)