| Abstract | A review of large-scale investigations of the determination of H is presented. The infrared period-luminosity relation of Cepheids gives distances accurate to about 2 percent to nearby galaxies. Based on the distances of M31, M33, N300 and N2403, a DM of 31.30 + or - 0.20 has been derived to the nearby Virgo cluster from the TF relation of spirals at four wavebands. Distances to more distant clusters extending up to a redshift of about 10,000 km/s give a value of H of 71 km/s/Mpc when these distances are normalized to a Virgo DM of 31.30. The magnitude limited all-sky samples of galaxies also give a value of H near 70 km/s/Mpc once the data are corrected for Malmquist bias. The best value of the global Hubble constant obtained from the redshift-distance data of Virgo and farther clusters, as well as the magnitude limited samples involving various methods of determining distances by different observers, is 73 km/s/Mpc. |
