🔭 Apparent Size Calculator

Calculate how large solar system objects appear in the sky from any observation point

🪐 Select Object & Observer

Object You're Observing

Observing From

Distance Scenario

Planetary distances vary as objects orbit the Sun

Object Diameter: —

Distance: —

Scenario: —

Object Diameter

Distance to Object

Apparent Size (Angular Diameter)

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Angular Diameter

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Degrees (°)

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Arcminutes (′)

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Arcseconds (″)

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Radians

Full Moon (31.1′)

Your Object

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δ = 2 × arctan(d / 2D)

δ = angular diameter (apparent size)
d = actual diameter of the object
D = distance from observer to object center