#astronomical instrument

• Almucantar — A terminological variant for almucantar, designating a small circle on the celestial sphere parallel to the horizon where all points share the same altitude; the term is also used to name a special astronomical instrument (a modified meridian transit circle) designed to measure time and stellar coordinates as they cross the same parallel of altitude.
• 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.
• Astroscope — A simplified optical instrument or astronomical device used historically or for educational purposes for the direct observation, visual examination, and projection of star charts onto the night sky. In older technical terminology, it defined a device equipped with interchangeable discs that aided in the rapid identification of constellations and planetary positions, functioning as a mechanical precursor to modern portable planetariums.