#sky survey

• Astrograph — An astronomical refractor or telescope with a wide field of view, specifically designed and optimized for astrophotography, sky mapping, and astrometry. This optical instrument lacks an eyepiece for direct visual observation, instead focusing light directly onto a photographic plate (historically) or a large-scale electronic digital sensor (CCD/CMOS), enabling the precise recording of star and galaxy positions.
• Astrometric — Belonging to astrometry, relating to astrometry; referring to the precise geometric measurement of positions, angular distances, and proper motions of celestial bodies on the celestial sphere. This term defines the methods, coordinate catalogs, instruments (such as scanning telescopes), or satellite data (such as those provided by the Gaia mission) used to establish fundamental star charts.