In the past, instruments that undergo evolution of calibration files or calibration software often required users to carry out their own recalibrations at their home sites. With OTFC, the HST data archives carry out the recalibration.
Previously, when instruments evolved in terms of calibration files or software, users typically had to recalibrate them themselves at their home locations. However, with OTFC, HST data archives now perform these recalibrations.