Numeric aperture | definition of numeric aperture by Medical dictionary
nu·mer·ic ap·er·ture (N.A.),
defined by the formula n sine a, where n is the refractive index of the medium between the object and objective lens and a is the angle between the central and the marginal rays entering the objective.
References in periodicals archive
With the addition of the Bioptechs Objective Heater system for high numeric aperture
applications, the FCS2 has become the prime micro-environmental system for long-term time-lapse studies, such as those Latimer's lab performs.