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Astronomy & optics

Distance modulus and apparent magnitude

Calculate apparent magnitude from absolute magnitude, distance and specified extinction.

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01

Your inputs

The starting values are an example.

Decimals: 12.5 · Thousands: 1,234.56. Follow the field instructions for lists.

02

Your result

Enter your values and select Calculate.

Your calculation will appear here.

Your result will include the relevant values and units.

Understand the calculation

Formula and example

How it is calculated

m − M = 5 × log₁₀(d/10 pc) + A

Worked example

An object with M = 5 mag at 100 pc, with no extinction, has an apparent magnitude of m = 10 mag.

Things to check

  • Absolute magnitude is the apparent magnitude at a distance of 10 pc.
  • The magnitudes and extinction must refer to the same photometric band. Cosmological corrections are excluded.