Positions come with an epoch
A measured stellar position belongs to a reference time. Proper motion describes how that position changes across the sky; parallax relates to the observer’s changing viewpoint as Earth orbits the Sun.
Gaia made the scale enormous
Gaia DR3 includes astrometric solutions — positions, parallax, and proper motion — for about 1.46 billion sources, with published uncertainty information and quality indicators.
Sources: ESA Gaia — Data Release 3
Catalog version belongs in provenance
A later data release can improve calibration, add sources, or alter measurements. Reproducible rendering therefore means preserving the catalog release or source version used for a chart.
Sources: ESA Gaia — Data Release Scenario · ESA Gaia — Data Release 3