Enter the observed irradiance and the reference flux into the Calculator. The calculator will evaluate the Apparent Magnitude.

## Apparent Magnitude Formula

M = -5*log(10) (Fx/Fx0)

Variables:

- MI is the Apparent Magnitude (())
- Fx is the observed irradiance
- Fx0 is the reference flux

To calculate Apparent Magnitude, divide the observed irradiance by the reference flux, take the log of the result, then multiply by -5.

## How to Calculate Apparent Magnitude?

The following steps outline how to calculate the Apparent Magnitude.

- First, determine the observed irradiance.
- Next, determine the reference flux.
- Next, gather the formula from above = M = -5*log(10) (Fx/Fx0).
- Finally, calculate the Apparent Magnitude.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

observed irradiance = 101

reference flux = 6