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Gravitational Lensing Deflection Angle Calculator

α = 4GM/(c²b) — light deflection in gravitational field.

Calculates the gravitational deflection angle of light passing a mass M at impact parameter b using the general-relativity weak-field formula α = 4GM/(c²b).

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Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

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  1. Fill in the inputs above using the units you already have.
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  3. Hover any result row for the underlying formula and intermediate values.

Formula

α (rad) = 4·G·M / (c²·b)

In depth

Calculates the gravitational deflection angle of light passing a mass M at impact parameter b using the general-relativity weak-field formula α = 4GM/(c²b).