# Microscope

In reference to a microscope, the minimum distance between two lines at which they are just distinct is called resolving limit (RL) and its reciprocal is called resolving power (RP).

Fig. 38

Î» = Wavelength of light used to illuminate the object,
Î¼ = Refractive index of the medium between object and objective,
Î¸ = Half angle of the cone of light from the point object, Î¼ sin Î¸ = Numerical aperture.

# Telescope

Smallest angular separations (dÎ¸) between two distant objects, whose images are separated in the telescope is called resolving limit. So, resolving limit, and resolving power , where a = aperture of objective.