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Engineers in a cleanroom, using CO 2 snow to clean a gold-coated test mirror for the James Webb Space Telescope. Carbon dioxide cleaning (CO 2 cleaning) comprises a family of methods for parts cleaning and sterilization, using carbon dioxide in its various phases. [1]
Testing of the figure is usually done by a Foucault knife-edge test or Ronchi test in amateur telescope making and with very sophisticated null testers on research telescope optics. For large mirrors, ion figuring is often used, in which a neutral atomic beam is used to remove material from the optics in a very controlled way.
Hartmann mask was invented as a tool to check the quality of large optical mirrors. It was especially useful for large non-spherical mirrors for telescopes. [1] For example, the illustration on the right shows the Hartmann mask used to test the Hale Telescope five-meter primary mirror.
The primary mirror in most modern telescopes is composed of a solid glass cylinder whose front surface has been ground to a spherical or parabolic shape. A thin layer of aluminum is vacuum deposited onto the mirror, forming a highly reflective first surface mirror. Some telescopes use primary mirrors which are made differently.
Technicians assemble 6 of the 18 first-surface mirrors used in the James Webb Space Telescope. A first-surface mirror or front-surface mirror (also commonly abbreviated FS mirror or FSM) is a mirror with the reflective surface being above a backing, as opposed to the conventional, second-surface mirror with the reflective surface behind a ...
A deformable mirror can be used to correct wavefront errors in an astronomical telescope. Deformable mirrors (DM) are mirrors whose surface can be deformed, in order to achieve wavefront control and correction of optical aberrations. Deformable mirrors are used in combination with wavefront sensors and real-time control systems in adaptive optics.
Objective: The first lens or curved mirror that collects and focuses the incoming light. Primary lens: The objective of a refracting telescope. Primary mirror: The objective of a reflecting telescope. Corrector plate: A full aperture negative lens placed before a primary mirror designed to correct the optical aberrations of the mirror.
This third telescope had the mirror damaged in 1694 by Newton while trying to clean it. It is thought that the mirror was later refigured by restorers accounting for its plugged eyepiece hole at an appropriate distance for a 6.25 inch focal length mirror and the new eyepiece position for the current mirror focal length of 8.5 inches.