We (Paul Price and Jim Bosch) would like to update the master calibrations used by default for HSC processing on lsst-dev, including both existing calibration frame types (flats, biases, darks, fringes) and two new calibration-like datasets:

• Sky Frames: measurements of the persistent (average) sky background in HSC visits across different filters.  This will be used in the new visit-level background estimation step (https://community.lsst.org/t/sky-subtraction/2415).
• Transmission Curves: measurements of the wavelength-dependent transmission for different parts of the optical system, which will be combined and added to Exposures in during ISR after the merge of DM-12375.

Both of these new processing steps will be enabled by default after the necessary calibrations are added to lsst-dev, which means any processing of HSC data with the default configuration on other platforms will also required those new calibrations to be added.  Instructions for adding the sky frames can be found in the above community.lsst.org link; while adding transmission curves can be done (after DM-12375) with:

setup obs_subaru

installTransmissionCurves.py /path/to/repo

Note that the above path is to the regular data repository root, not a calibRoot; transmission curves are not yet versioned (they will be in the Gen3 butler, if not earlier).

Both of these steps will only be used in HSC processing for now.  They could be enabled for other cameras once the work is done to provide the necessary calibrations for those cameras.

As per our policy on modifications to /datasets:

• Description and reason for addition/change/deletion: updates to the existing calibration frames reflect our most up-to-date understanding of the camera's characteristics.  The new datasets enable new processing steps that improve the quality of the reductions.
• Target top-level-directory for location of addition/change/deletion: /datasets/hsc/repo
• Organization of data:
  • calibration and sky frames will go in a new subdirectory of /datasets/hsc/repo/calibs, and the /datasets/hsc/repo/CALIB symlink will be updated to point to the new subdirectory
  • transmission curves will go into /datasets/hsc/repo/transmission
• Other necessary domain knowledge as identified by project members relating to the contents of the data: provided in the community.lsst.org link above