# combined magnitude

Combined magnitude is the total brightest of two or more celestial objects, such as the stars
of a binary system that appear as a single
point to the naked eye. Unfortunately, this can't be found simply by adding
the separate magnitudes, *m*_{1} and *m*_{2},
because the magnitude scale is logarithmic.
Instead the combined magnitude, *m*, has to be calculated from the
formula:

*m* = *m*_{1} - 2.5 log {1 + antilog [-0.4 (*m*_{2} - *m*_{1})]}.