scara magnitudinii astronomice.
scara de mai jos este dată ca un instrument instructiv, pentru a da o generalidea a modului în care funcționează scara de magnitudine. Scara de mai jos este destinată să fie aproximativ vizuală; eficiența detectării ochiului uman (adaptată la întuneric) atinge vârfuri de aproximativ 495 nanometri, în timp ce vârful fotoelectric v formal (o bandă filtrată destinată să fie aproape de vizual) este de aproximativ 550 nm; CCDs tind să atingă un vârf de aproximativ 700 nm., Exemplele sunt date forinteger valorile nu sunt „exact”, în care obiecte cerești câștiga măsurată cu o precizie sau 0.1 sau 0.01 mărime; de exemplu,Sirius strălucește la V = -1.47 (Yale Stea Strălucitoare Catalog),și planeta Venus variază în luminozitate în general, de magnitudine 4,5 la -3.7. Rețineți că o cometă cu magnitudinea de 5 nu va fi la fel de ușor s-o vada ca o stea de magnitudinea 5, pentru că aceeași cantitate de brightnessthat este concentrată într-un punct pentru steaua este răspândit peste aregion din cer pentru un difuze cometa cu o relativ mare comă.,
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