Data and Screen Photographs for an Instrument-Limited Two-Watch Chronometry Case Study

This dataset contains the raw observation records and timegrapher screen photographs underpinning an instrument-limited, two-watch chronometry case study. It includes 128 measurements from an Omega Calibre 8912 and a Victorinox Airboss 241506, recorded across four experimental cycles at four static positions and two winding states. Cycle 1 is retained as preliminary data. Cycles 2 to 4 followed the locked standardised protocol, using a five-minute settling interval, 60-second acoustic measurements, and immediate 60-second technical repeats. The archive includes a machine-readable CSV dataset, a data dictionary, a file manifest with SHA-256 checksums, all 128 screen photographs, and a convenience Excel workbook. The data include acoustic rate, displayed amplitude, beat error, positional condition, winding state, measurement timing, reference offsets, and instrument settings. Amplitude values for the Omega co-axial movement should be interpreted cautiously as exploratory timegrapher readings. This deposit is intended to support transparency, inspection, and reproducibility of the descriptive analysis reported in the associated manuscript.