Description: Optics is the science of light and its interactions with matter, and the art of constructing instruments that make use of the general principles of light–matter interactions. In astronomy, the "optics" of a telescope or instrument are those parts that guide light towards a detector, notably mirrors, lenses, masks, slits, or waveguides where visible light is concerned, as well as dispersive elements such as prisms and gratings that produce spectra. Active optics is the term for a mirror kept in the correct shape by active mechanical elements ("actuators"), while adaptive optics is a system whereby a mirror is quickly deformed in just the right way to counteract atmospheric disturbances (the "twinkling" of stars). The adjective "optical" is also used to refer to astronomy using visible light.

Related Terms:

• Reflecting Telescope
• Refracting Telescope
• Telescope
• Adaptive Optics
• Lens
• Mirror

Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".