Observatories on Earth
The telescopes and detectors on the ground that watch the deep sky: giant mirrors on desert mountains, radio dishes in quiet valleys, laser rulers that feel gravitational waves, and ice and water that catch neutrinos. Click any of them on the map.
Around the Earth, now
--:-- · DAY AND NIGHT AS NOWColours: what each one detects. Filled: working · ring: being built · grey: historic. Telescopes for visible light glow while it is night there; radio, gravitational-wave, neutrino and particle detectors work day and night. marks where the Sun is overhead.
How big? How sharp?
What the air lets through
WAVELENGTH, LOG SCALEThe air is clear only in two broad windows, visible light and radio, and in a few narrow ones in the infrared and at millimetre waves, which is why those telescopes climb high and dry mountains. Gamma rays, X-rays and most ultraviolet never reach the ground: they need observatories in space. Ground gamma-ray telescopes see them only indirectly, by the flash they make in the air. Click a row to show those observatories on the map.
Working together
ONE TELESCOPE THE SIZE OF THE EARTHWhy up there?
ALTITUDE · AIR AND WATER VAPOUR ABOVEEvery 8 km up leaves nearly two-thirds of the air below; water vapour, which blocks infrared and millimetre waves, thins out four times faster, so at ALMA's 5,000 m only about a twelfth of it remains overhead. Dark skies matter too: La Palma, Hawaiʻi and Chile protect their night skies by law, and radio telescopes sit in radio-quiet zones (Green Bank, the Karoo, the Murchison).
Years of discovery
CLICK A DOTObservatory facts from each project's own pages (checked 2026-10-30); coordinates checked against the Astropy site registry. Earth: NASA Blue Marble and Earth at Night (Wikimedia Commons). Banner: Deep Sky Monitor.