corrector plate

corrector plate

[kə′rek·tər ‚plāt]
(optics)
A thin lens or system of lenses used to correct the spherical aberration of a spherical lens or the coma of a parabolic lens; used particularly in telescopes such as the Schmidt telescope. Also known as correcting plate.
References in periodicals archive ?
In common with SCTs, Schmidt cameras brought light to a focus using a catadioptric combination of a refracting corrector plate followed by a spherical short-focal-length primary mirror.
The process of converting an amateur f/10 SCT into an f/2 Schmidt camera required the secondary mirror and its mounting to be completely removed from the centre of the corrector plate, and replaced with a new assembly which could be clamped in its place.
If this was not done, any snag in the cables would put force directly onto the camera, and thence onto the thin corrector plate onto which it was clamped.
The corrector plate had to be removed from the front of the tube, and the secondary mirror and its holder unscrewed from the plate's centre.
Once the corrector plate was isolated, a new assembly could be clamped in place of the old secondary mirror holder; this new assembly could receive either a HyperStar unit, or a new replacement for the old secondary mirror holder.
The Schmidt optic corrector plate is suspended from its mounting ring 3-meters (10 feet) above the telescope's primary mirror, and will be used to correct spherical aberration after the telescope is on-orbit.
The project soon ran into technical difficulties, partly because the astronomers wanted to build two telescopes in one--a Schmidt camera for wide-angle photography, which could be converted into a conventional Cassegrain reflector for spectroscopy when the giant corrector plate was removed.
In addition, many Barlow lenses (used for necessary focal extension) and corrector plates are coated with anti-reflection (AR) coatings that significantly reduce UV throughput.