(mv) The apparent magnitude of a star as estimated by the human eye. The eye is capable of ranking stars in order of brightness and estimating equality between two stars, or a star and an artificial source. These were the only ways to measure visual magnitudes until the advent of the photovisual magnitude technique and photoelectric photometry. Now that magnitudes are measured precisely by photometers, it is more usual to use the apparent V magnitude.
Subjects: Astronomy and Astrophysics.