💡 Apparent Brightness Calculator

Calculate how bright solar system objects appear from any observation point using the magnitude scale

🌟 Select Object & Observer

Object You're Observing

Observing From

Distance Scenario

Planetary distances vary as objects orbit the Sun

Absolute Magnitude (M): —

Distance: —

Scenario: —

Absolute Magnitude (M)

Brightness at 10 parsecs: Sun = +4.83 · Sirius = +1.42 · Proxima Centauri = +15.5

Apparent Magnitude (m)

Negative = brighter: Sun = −26.74 · Full Moon = −12.74 · Naked eye limit ≈ +6.5

Distance

Custom mode uses the stellar distance modulus — best for self-luminous objects. Use Solar System Objects mode for reflected-light bodies.

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Apparent Magnitude

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Visual Irradiance

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vs Full Moon

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vs Sun from Earth

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Observable With

Longer bar = brighter. Scale runs from Sun (−26.74) on the left to HST limit (+31.5) on the right.

💡

m = M + 5 × log₁₀(d / 10 pc)

m = apparent magnitude (how bright it looks)
M = absolute magnitude (brightness at 10 parsecs)
d = distance from observer in parsecs