la escala de magnitud astronómica.
la escala de abajo se da como una herramienta instructiva, para dar una idea general de cómo funciona la escala de magnitud. La escala de abajo está pensada para ser más o menos visual; la eficiencia de detección del ojo humano (adaptada a la oscuridad) alcanza los picos alrededor de 495 nanómetros, mientras que el pico fotoeléctrico formal V (una banda filtrada destinada a estar cerca de lo visual) es de alrededor de 550 nm; los CCD tienden a alcanzar un pico alrededor de 700 nm., Los ejemplos se dan para los valores de entero no son «exactos», en que los objetos celestes son a menudo medidos a una precisión o magnitud 0.1 o 0.01; por ejemplo,Sirio brilla en V = -1.47 (catálogo de estrellas brillantes de Yale), y el planeta Venus varía en brillo generalmente de magnitud-4.5 a -3.7. Tenga en cuenta que un cometa de magnitud 5 no será tan fácil de ver como una estrella de magnitud 5, porque la misma cantidad de brillo que se concentra en un punto para la estrella se extiende sobre una región del cielo para un cometa difuso con una coma relativamente grande.,
Magnitude Needed to see an object of this brightness* Examples -26 the sun -13 full moon -6 crescent moon -4 naked eye: easy even from large cities planet Venus -2 naked eye planet Jupiter -1 naked eye brightest star, Sirius; totally- eclipsed moon; C/1995 O1 (Hale- Bopp) near peak 0 naked eye: difficult if near bright summer evening star artificial lights but generally Vega; C/1996 B2 visible even from large cities (Hyakutake) at peak +1 naked eye: brilliant as seen from planet Saturn dark, rural areas +2 naked eye: difficult but visible from stars of Big Dipper small cities and suburbs; diffuse Halley's comet in objects such as comets may require 1986 near peak small binoculars from urban areas 3 naked eye: rural, suburban, small city faintest naked-eye binoculars: bright, urban areas stars visible from many smaller cities/inner suburbs; 4 naked eye: (outer) suburbs faintest naked-eye binoculars: cities (stars), suburban stars visible from areas (diffuse objects such as comets) many smaller cities/(outer) suburbs 5 generally binocular objects from urban moons of Jupiter and suburban areas; faintest naked-eye stars visible from "dark" rural areas located some 40 miles (60 km) from major cities 6 binocular objects from suburban areas; planet Uranus faintest naked-eye stars visible from "dark" rural areas located some 100 miles (150 km) from major cities 7 binoculars; faintest naked-eye stars brightest minor visible from "dark" rural areas planet (asteroid) located some 140 miles (200 km) from and about 1-2 major cities and some 30 miles (50 km) comets each year from nearest town of population 5000 or so 8 binocular objects; from urban areas, such planet Neptune objects may only be visible with small telescopes 10 from dark sky, objects visible with at any given 20x80 binoculars; from brighter sites, time, there are a larger telescope is needed usually a couple of comets this bright 11 general limiting visual brightness# of comets with a 15-cm-aperture reflector 12 general limiting visual brightness# of at any given time, comets with a 20-cm-aperture reflector there are usually a half dozen comets this bright 13 general limiting visual brightness# of comets with a 25-cm-aperture reflector 14 general limiting visual brightness# of Pluto at its brightest stars with a 20-cm-aperture reflector 15 general limiting visual brightness# of comets with a 50-cm-aperture reflector 19 general limiting photographic brightness# of comets with a 50-cm-aperture reflector 21 general limiting brightness of stars with a 60-cm-aperture reflector + CCD 22 general limiting brightness# of comets with a CCD and 150-cm-aperture reflector* naked-eye viewing assumes 20-20 vision (corrected or uncorrected)# from a dark, rural site; "visual" as compared to "photographic" or "CCD-detected"; "reflector" means "reflecting telescope"
ICQ