Absolute -band magnitudes and mass-to-light ratios of Galactic globular clusters

We have used Hubble Space Telescope and ground-based photometry to determine total V -band magnitudes and mass-to-light ratios of more than 150 Galactic globular clusters. We do this by summing up the magnitudes of their individual member stars, using colour-magnitude information, Gaia DR2 proper motions, and radial velocities to distinguish cluster stars from background stars. Our new magnitudes confirm literature estimates for bright clusters with $V