How we observe the universe
From mountaintop optical giants to space telescopes and gravitational-wave detectors — 61 observatories and telescopes across 108 interconnected entities, spanning every band of the electromagnetic spectrum and beyond.
18 observatories · 25 telescopes · 18 space telescopes · 11 instruments · 10 sky surveys · 12 observing bands · 3 observing sites · 11 organizations
Largest telescopes
See all →FAST
Radio dish · 500 m
FAST, the Five-hundred-metre Aperture Spherical Telescope in China, is the world's largest single-dish radio telescope, used to study pulsars and fast radio bursts.
Green Bank Telescope
Radio dish · 100 m
The Robert C. Byrd Green Bank Telescope in West Virginia is the world's largest fully steerable radio telescope, with a 100-metre dish.
Extremely Large Telescope
PlannedOptical / infrared reflector · 39.3 m
ESO's Extremely Large Telescope, under construction in Chile, will be the world's largest optical/infrared telescope with a 39-metre segmented mirror. It is not yet operational.
Thirty Meter Telescope
PlannedOptical / infrared reflector · 30 m
The Thirty Meter Telescope is a planned 30-metre optical/infrared telescope; its site remains the subject of ongoing decisions. It is not yet operational.
James Clerk Maxwell Telescope
Submillimeter dish · 15 m
The James Clerk Maxwell Telescope on Mauna Kea is a 15-metre submillimeter telescope and a station of the Event Horizon Telescope.
Atacama Pathfinder Experiment
Submillimeter dish · 12 m
APEX is a 12-metre submillimeter telescope in the Atacama Desert, a pathfinder for ALMA studying cold dust and gas.
Southern African Large Telescope
Optical spectroscopic reflector · 11 m
SALT in Sutherland, South Africa is the largest single optical telescope in the Southern Hemisphere, a sibling of the Hobby–Eberly design.
Gran Telescopio Canarias
Optical / infrared reflector · 10.4 m
The Gran Telescopio Canarias on La Palma is one of the largest single-aperture optical telescopes in the world, with a 10.4-metre segmented mirror.
Keck I
Optical / infrared reflector · 10 m
Keck I is one of two 10-metre Keck telescopes on Mauna Kea, using a segmented primary mirror of 36 hexagonal segments.
Discover
All Observatories
Every observatory facility in the encyclopedia.
Ground-Based Observatories
Observatory facilities on the Earth's surface.
Space Telescopes
Observatories that operate from orbit and beyond.
Optical Telescopes
Telescopes that gather visible light.
Radio Telescopes
Telescopes and arrays that observe radio waves.
Infrared Telescopes
Telescopes that observe heat — infrared light.
X-ray Telescopes
Observatories of the high-energy X-ray universe.
Gamma-ray Telescopes
Observatories of the most energetic light.
Solar Observatories
Telescopes and missions that study the Sun.
Survey Telescopes
Facilities that map large areas of the sky.
Sky Surveys
Systematic surveys mapping the cosmos.
Astronomical Instruments
The cameras and spectrographs that gather the data.
Largest Telescopes
The biggest light-collecting apertures in the world.
Historic Telescopes
The instruments that founded modern astronomy.
Future Telescopes
Observatories under construction — not yet operational.
Gravitational-Wave Observatories
Detectors that sense ripples in spacetime.
Neutrino Observatories
Detectors that catch ghostly cosmic particles.
Multi-Messenger Astronomy
Observatories that combine light, waves, and particles.
Data & provenance
The observatories encyclopedia is curated from authoritative public sources — NASA, ESA, ESO, NOIRLab, NSF, NRAO, NAOJ, STScI, and observatory pages. Apertures, altitudes, first-light dates, operators, and instruments are well-established public facts; uncertain values are omitted, and future facilities are clearly marked as not yet operational. See the source quality page.