Star Flux

Flux Apparent Magnitude

Luminosity Formula

F=L/4πd2

  • F = Flux (watts/square meter)
  • L = Luminosity (watts)
    • Watts = Joules/Second
  • D = Distance from star (meters)

Apparent Magnitude

Apparent Magnitude - Wikipedia

The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of {\displaystyle {\sqrt[{5}]{100}}}, or about 2.512.

m2-m1 = -2.512 log(B2/B1)

  • m = magnitude of object
  • b = actual brightness of object

With B1 being the brightness of the sun, being a brightness of 1, and B2 being the brightness of the star generated in this calculator, the formula can be rewritten as:

mstar-(-26.74) = -2.512 log(Bstar)

Apparent magnitude of the Sun from Earth: -26.74

How to use this calculator

  1. Enter two of the following values (leave the third value blank):
  2. Press the "Generate" Button to calculate the missing value.

The Sun generates 3.828 x 1026 joules of energy per second. (Source)

The Astronomical Unit (AU) is 1.495978707×1011 meters, the distance between the Earth and the Sun.

Luminosity Distance Flux Apparent Magnitude
Joules/Second Suns Meters AU Watts/m2 Suns