0 Assigned ID: 392 ----- Attempting Submission 1 (Fri Apr 10 07:13:18 GMT 2015) ----- Tip of the red giant branch (TRGB) distance measurements with HST constitute a foundational component of the Cosmicflows compilation of extragalactic distances. Cosmicflows is a program to determine the Hubble Constant, map peculiar velocities, and recover the underlying matter density field. With ACS on HST, TRGB distances can be established with rms 5% accuracy for essentially any galaxy within 10 Mpc. Presently between our observations and archival material from past years we have TRGB results for 384 galaxies. In cycle 22, 68 additional galaxies are being observed. Another half dozen complicated cases from earlier years await exploitation. While most of this material will have been reasonably treated by others, we argue that it is important that the ensemble be analyzed in a consistent manner to minimize systematics in the measurement of distances. The Pop II based absolute scale of the TRGB distances will be reviewed. The full collection of HST material related to TRGB observations for almost 500 galaxies will be ported to the Mulkulski Archive for Space Telescopes. RESOLVED STELLAR POPULATIONS 0 Regular false false false false false SUPPORTED