Search results
Results from the WOW.Com Content Network
A dioptre ( British spelling) or diopter ( American spelling ), symbol dpt, is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, 1 dpt = 1 m−1. It is normally used to express the optical power of a lens or curved mirror, which is a physical quantity equal to the reciprocal of the focal length ...
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)
Prism spectacles with a single prism perform a relative displacement of the two eyes, thereby correcting eso-, exo, hyper- or hypotropia. In contrast, spectacles with prisms of equal power for both eyes, called yoked prisms (also: conjugate prisms, ambient lenses or performance glasses) shift the visual field of both eyes to the same extent.
Hygrometer. Dry / Wet-bulb temperature. v. t. e. Psychrometrics (or psychrometry, from Greek ψυχρόν (psuchron) 'cold', and μέτρον (metron) 'means of measurement'; [1] [2] also called hygrometry) is the field of engineering concerned with the physical and thermodynamic properties of gas - vapor mixtures .
In optics, spherical aberration ( SA) is a type of aberration found in optical systems that have elements with spherical surfaces. This phenomenon commonly affects lenses and curved mirrors, as these components are often shaped in a spherical manner for ease of manufacturing. Light rays that strike a spherical surface off-centre are refracted ...
The calculated air mass reaches a maximum of 11.13 at 86.6°, becomes zero at 88°, and approaches negative infinity at the horizon. The plot of this formula on the accompanying graph includes a correction for atmospheric refraction so that the calculated air mass is for apparent rather than true zenith angle.
In astronomy, the bolometric correction is the correction made to the absolute magnitude of an object in order to convert its visible magnitude to its bolometric magnitude. It is large for stars which radiate most of their energy outside of the visible range.
The Taylor knock-out factor, also called Taylor KO factor or TKOF, is a formulaic mathematical approach for evaluating the stopping power of hunting cartridges, developed by John "Pondoro" Taylor in the middle of the 20th century. Taylor, an elephant hunter and author who wrote two books about rifles and cartridges for African hunting, devised ...
In physics, Hooke's law is an empirical law which states that the force (F) needed to extend or compress a spring by some distance (x) scales linearly with respect to that distance—that is, F s = kx, where k is a constant factor characteristic of the spring (i.e., its stiffness), and x is small compared to the total possible deformation of ...
K correction converts measurements of astronomical objects into their respective rest frames. The correction acts on that object's observed magnitude (or equivalently, its flux).