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abstraction > mathematical concept > number > quantity > radiation measurement > magnitude > apparent magnitude

apparent magnitude
subject			fact

apparent magnitude	has definition A measure of how bright a star looks in the sky. The brighter the star, the smaller the apparent magnitude. A star that is one magnitude brighter than another (e.g., +1 versus +2) looks 2.5 times brighter. The brightest star of all, of course, is the Sun, whose apparent magnitude is -26.74, followed by Sirius, whose apparent magnitude is -1.46, Canopus (-0.72), Alpha Centauri (-0.27), Arcturus (-0.04), and Vega (+0.03). Stars of the Big Dipper are fainter, most of them around magnitude +2. On a clear, dark night, the unaided eye can see stars as faint as apparent magnitude +6, and the largest telescopes penetrate to apparent magnitude +30.
	has definition Measure of the observed brightness of a celestial object as seen from the Earth. It is a function of the star's intrinsic brightness, its distance from the observer, and the amount of absorption by interstellar matter between the star and the observer. The mv, of Sun, -26.5 mag. A sixth-magnitude star is just barely visible to the naked eye.
	is a kind of magnitude
radiation measurement	has unit radiation unit
number	has value

Kinds of apparent magnitude :

• infrared magnitude (7 kinds, 25 facts) - The magnitude derived from the observations at an infrared wavelength
• photoelectric magnitude (2 facts) - The magnitude of an object as measured with a photoelectric photometer. (m_pe) (antiquated term)
• photographic magnitude (2 facts) - The magnitude of an object as measured on the traditional photographic emulsions, which are sensitive to a slightly bluer region of the spectrum than is the human eye. (m_ph)(antiquated term)
• photovisual magnitude (2 facts) - The magnitude of an object as measured photographically by filters and emulsions that are sensitive to the same region of the spectrum as the human eye. (antiquated)