unconditional; not restricted or limited by any conditions; existing independently rather than in relation to something else; (of measurements, etc.) regarding a value based only on a specific standard regardless of external conditions (e.g. absolute temperature, absolute weight)

A measure of the brightness of a star or other celestial body. Lower values represent brighter objects. Common systems include 目视星等 mù​shì​xīng​děng and 绝对星等 jué​duì​xīng​děng.