ARCHIVE of timing and maser data at Green Bank. FILES of form: YYYY_MM.t0 (e.g., 2001_04.t0) or YYYY_MM.ttac Are hourly data for one month. 1pps offsets of site time (Sigma Tau maser) vs GPS and VLBI formatters. The column labeled "TAC" or "ST-TAC" is Site Time vs. GPS. If offset is positive, Site Time pulse precedes GPS. FILE: "time_gbt.dat" is a summary, updated daily of the "ST-TAC" offset, which is labeled in this file as "NIST-REF". Data earlier than 1995: see files 'MMMYY.TP', and 'README.timer' and 'timer.log' for explanations. STmaser.log : log of adjustments to the Sigma Tau maser. SAOmaser.log : log of adjustments to the SAO maser.