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Prentice's rule, named so after the optician Charles F. Prentice, is a formula used to determine the amount of induced prism in a lens: = where: P is the amount of prism correction (in prism dioptres) c is decentration (the distance between the pupil centre and the lens's optical centre, in millimetres)
The free-air correction is the amount that must be added to a measurement at height to correct it to the reference level: δ g F = 2 g R × h {\displaystyle \delta g_{F}={\frac {2g}{R}}\times h} Here we have assumed that measurements are made relatively close to the surface so that R does not vary significantly.
Amblyopia. Anisometropia is a condition in which a person's eyes have substantially differing refractive power. [1] Generally, a difference in power of one diopter (1D) is the threshold for diagnosis of the condition . [2] [3] Patients may have up to 3D of anisometropia before the condition becomes clinically significant due to headache, eye ...
It can readily be seen that the formula above for motion along the equator follows from the more general equation below for any latitude where along the equator v = 0.0 and = a r = 2 Ω u cos ϕ + u 2 + v 2 R {\displaystyle a_{r}=2\Omega u\cos \phi +{\frac {u^{2}+v^{2}}{R}}}
After simplifying the final equation is found: F F c = 1 − x F ⇒ F c = F 1 − x F = 1 1 F − x ⇒ F = 1 1 F c + x {\displaystyle {\begin{aligned}&&{\frac {F}{F_{\text{c}}}}&=1-xF\\&\Rightarrow &F_{\text{c}}&={\frac {F}{1-xF}}={\frac {1}{{\frac {1}{F}}-x}}\\&\Rightarrow &F&={\frac {1}{{\frac {1}{F_{\text{c}}}}+x}}\end{aligned}}}
It deviates in the ultraviolet and infrared regions. In optics, Cauchy's transmission equation is an empirical relationship between the refractive index and wavelength of light for a particular transparent material. It is named for the mathematician Augustin-Louis Cauchy, who originally defined it in 1830 in his article "The refraction and ...
Aberration (astronomy) A diagram showing how the apparent position of a star viewed from the Earth can change depending on the Earth's velocity. The effect is typically much smaller than illustrated. In astronomy, aberration (also referred to as astronomical aberration, stellar aberration, or velocity aberration) is a phenomenon where celestial ...
Calculate U 1, U 2 and L, and set initial value of λ = L. Then iteratively evaluate the following equations until λ converges: sin σ = ( cos U 2 sin λ ) 2 + ( cos U 1 sin U 2 − sin U 1 cos U 2 cos λ ) 2 {\displaystyle \sin \sigma ={\sqrt {\left(\cos U_{2}\sin \lambda \right)^{2}+\left(\cos U_{1}\sin U_{2 ...
Stribeck curve. The Stribeck curve is a fundamental concept in the field of tribology. It shows that friction in fluid-lubricated contacts is a non-linear function of the contact load, the lubricant viscosity and the lubricant entrainment speed. The discovery and underlying research is usually attributed to Richard Stribeck [1] [2] [3] and Mayo ...
This equation can be rearranged into the following equation q = − k μ ( 1 + D K μ k 1 p ) ∂ p ∂ x . {\displaystyle q=-{\frac {k}{\mu }}\left(1+{\frac {D_{\mathrm {K} }\mu }{k}}{\frac {1}{p}}\right){\frac {\partial p}{\partial x}}\,.}