Description: Resolution, or angular resolution is the smallest angle between two close point-like objects that can be seen as just separated. It can also be thought of as the spread of a point-like object (such as a star), that is mainly due to optics of the telescope. This is a very important characteristic of telescopes, as telescopes with higher angular resolution enable us to visually separate stars seen very close to each other as well as to see finer details in extended objects such as nebulae and galaxies. Two stars with angular separation smaller than the resolution will appear as a single object. The resolution of a telescope can be improved by increasing the size of its light collecting mirror or lens. It also depends on the wavelength and becomes poorer as the wavelength increases.

Related Terms:

• Telescope
• 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".