Quality Control and
Data Processing

A complete set of GRAVITY calibrations consists of dark exposures, flat-fields, wavelength calibrations, calibrations for the pixel-to-visibility matrix (P2VM), and on-sky astronomical calibrators. They need to be processed in a certain order.

The darks are processed first into a master DARK. Flat fields, wavelength, and P2VM calibrations are typically processed together in one step for each set up. Their processing requires a master DARK (or optionally a raw dark exposure). Output files are a BAD pixel map, a master FLAT, a WAVE, and a P2VM calibration product. All these products are needed to process calibrators or science observations into raw visibilities.

A graphical representation of the GRAVITY calibration cascade can be found here.