Astro*Dictionary
by Michael Erlewine

3 articles for
"Magnitude"

Magnitude [Astro*Index]

An indication of size or influence according to an agreed upon standard.

 

See also: ♦ Absolute Magnitude ♦ Apparent Magnitude ♦ Bolometric Magnitude ♦ Photographic Magnitude ♦ Stellar Magnitude

 

Magnitude [Munkasey M.]

There are three brightness measurements of a celestialbody, and these are: Apparent Magnitude: This value depends both on the body's intrinsic brightness and its distance from the viewing observer. Absolute Magnitude: The Apparent Magnitude of a body as observed from 10 parsecs. Luminosity: The total energy of a body expressed as a multiple of the Sun's output.

 

See also: ♦ Absolute Magnitude ♦ Apparent Magnitude ♦ Bolometric Magnitude ♦ Photographic Magnitude ♦ Stellar Magnitude

 

Magnitude [DeVore]

An adopted arbitrary geometric scale whereby to indicate the brightness of a celestial object; according to which an increase of 5 magnitudes corresponds to 100-fold decrease in brightness.

Apparent Magnitude
As it actually appears — ranging from -26.7 for our Sun to + 20 for the faintest stars which can be photographed by the largest telescope.

Absolute Magnitude
As it would be perceived if removed to a point from which its parallax would be 0.1" of arc — ranging from -5 for the brightest of stars to +15 for the faintest, with our Sun about +5. The faintest star visible to the unaided eye is of the sixth magnitude. Since greenish yellow registers best on the eye and blue-violet registers best on the photo-plate, magnitudes vary somewhat according to the method of observation employed.

 

See also: ♦ Absolute Magnitude ♦ Apparent Magnitude ♦ Bolometric Magnitude ♦ Photographic Magnitude ♦ Stellar Magnitude