Glossary term: Angular Resolution
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:
See this term in other languages
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".
If you notice a factual error in this glossary definition then please get in touch.
In Other Languages
- Arabic: الدفة الزاوية
- Bengali: কৌণিক বিভেদন
- German: Auflösungsvermögen
- Spanish: Resolución Angular
- French: Résolution angulaire
- Italian: Risoluzione angolare
- Japanese: 角分解能 (external link)
- Nepali: कोणीय विभेदन
- Brazilian Portuguese: Resolução angular
- Simplified Chinese: 角分辨率
- Traditional Chinese: 角分辨率
Related Media
A binary brown dwarf system revealed
Caption: This image presents a nearby system of brown dwarfs, objects that fall between planets and stars in mass and do not sustain long-term nuclear fusion in their cores. Located about 6.5 light-years from Earth, this system (known as Luhman 16) is the third closest system to the Solar System after the Alpha Centauri system and Barnard's Star. It was initially observed as what seemed to be a single faint source of infrared light. Brown dwarfs are often difficult to study because of their low brightness, especially in visible light. However they shine brighter in infrared light due to their cooler effective temperatures.
The comparison highlights the importance of observational resolution. The image at the center, taken by NASA’s Wide-field Infrared Survey Explorer (WISE), shows the system as a single blurred object due to its lower resolution (WISE has a resolution of roughly 6 arcseconds). A highlighted zoomed-in view from the Gemini South Observatory in Chile reveals that this “single” source is actually a binary system of two brown dwarfs. The improved angular resolution (roughly 0.6 arcseconds) allows astronomers to separate the two objects clearly, demonstrating how higher-resolution observations uncover hidden structures in the universe. While the Gemini telescope is situated on the Earth and thus is affected by the blurring effects of the Earth's atmosphere, it has a substantially larger mirror than the WISE telescope (8m wide vs. 40cm wide) meaning it can achieve much higher resolutions.
Credit: NASA/JPL/Gemini Observatory/AURA/NSF
credit link
License: PD Public Domain icons
