Hans Wolter
Encyclopedia
Hans Wolter was a German physicist who designed an aplanatic system of grazing incidence
mirrors that satisfied the Abbe sine condition
(i.e. free of both spherical aberration
and coma
).
Wolter showed such a system could be produced using a combination of a paraboloid
with either a hyperboloid or ellipsoid secondary. The three simplest designs are outlined and are known as Wolter telescope
s of types I, II and III.
Angle of incidence
Angle of incidence is a measure of deviation of something from "straight on", for example:* in the approach of a ray to a surface, or* the angle at which the wing or horizontal tail of an airplane is installed on the fuselage, measured relative to the axis of the fuselage.-Optics:In geometric...
mirrors that satisfied the Abbe sine condition
Abbe sine condition
The Abbe sine condition is a condition that must be fulfilled by a lens or other optical system in order for it to produce sharp images of off-axis as well as on-axis objects...
(i.e. free of both spherical aberration
Spherical aberration
thumb|right|Spherical aberration. A perfect lens focuses all incoming rays to a point on the [[Optical axis|optic axis]]. A real lens with spherical surfaces suffers from spherical aberration: it focuses rays more tightly if they enter it far from the optic axis than if they enter closer to the...
and coma
Coma (optics)
In optics , the coma in an optical system refers to aberration inherent to certain optical designs or due to imperfection in the lens or other components which results in off-axis point sources such as stars appearing distorted, appearing to have a tail like a comet...
).
Wolter showed such a system could be produced using a combination of a paraboloid
Paraboloid
In mathematics, a paraboloid is a quadric surface of special kind. There are two kinds of paraboloids: elliptic and hyperbolic. The elliptic paraboloid is shaped like an oval cup and can have a maximum or minimum point....
with either a hyperboloid or ellipsoid secondary. The three simplest designs are outlined and are known as Wolter telescope
Wolter telescope
A Wolter telescope is a telescope for X-rays using only grazing incidence optics. Visible light telescopes are built with lenses or parabolic mirrors at nearly normal incidence. Neither works well for X-rays. Lenses for visible light are made of a transparent material with an index of refraction...
s of types I, II and III.