Magnitude of eclipse

The magnitude of eclipse is the fraction of the angular diameter of a celestial body being eclipsed.^[1] This applies to all celestial eclipses. The magnitude of a partial or annular solar eclipse is always between 0.0 and 1.0, while the magnitude of a total solar eclipse is always greater than or equal to 1.0, and has a theoretically maximum value of around 1.12.

This measure is strictly a ratio of diameters and should not be confused with the covered fraction of the apparent area (disk) of the eclipsed body. Neither should it be confused with the astronomical magnitude scale of apparent brightness.