It is shown that in contrast to a traditional fluorescence spectroscopy with the parallel beams of light, in which the kinetic fluorescence decays are collected at the so-called magic-angle of theta(mag) = 54.7 degrees, in the fluorescence microscopy, the value of the magic-angle depends on the numerical aperture (NA) of a microscope objective and on the refractive index (n) of an immersion liquid used. Two methods enabling the determination of the magic-angle values corresponding to different values of NA/n, are discussed. It is shown that theta(mag) changes from a value of 54.7 degrees at the NA/n -> 0, to a value of 45 degrees with NA/n -> 1. Also in contrast to a traditional fluorescence spectroscopy, in the fluorescence microscopy the term I-parallel to(t) + 21(perpendicular to) (t) does not represent the total fluorescence intensity I-tot(t), because the resulting fluorescence decay I-parallel to(t) + 21(perpendicular to) (t) is contributed by the dynamic evolution of excited fluorophores. A correctly defined total fluorescence intensity solely represents the kinetic evolution of excited fluorophores, and in the fluorescence microscopy it equals I-tot(t) = 3I(mag)(t), where I-mag(t) represents the fluorescence intensity detected at theta(mag) corresponding to a particular NA/n value. If the correct (true) decay of I-mag(t) is substituted into the denominator in the expression for the emission anisotropy r(t), r(t) is a (multi)exponential function of time and it accounts for the high-aperture excitation-detection conditions.