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Observing / Telescopes

Ground-based telescopes

Interactive map of major ground-based observatories, night-sky webcams and real-time public data.

Filter by type:40 observatories
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Explore the map

Click a marker to discover a ground-based observatory, its webcams, latest observation images and major discoveries.

Outreach / Understand

Cosmic messengers

The universe doesn’t only send us light. It also emits gravitational waves, neutrinos and cosmic rays, distinct “messengers” that need different instruments to capture. Here is a no-jargon tour to understand how we “listen” to the cosmos.

The electromagnetic spectrum

All the light we capture is an electromagnetic wave. But its wavelength spans 17 orders of magnitude: from ultra-energetic gamma rays (smaller than an atom) to radio waves of several kilometres. Each band reveals a different universe, and every telescope is specialised in a particular window.

10-1210-1010-810-610-410-2100102104WAVELENGTH (m): LOG SCALEγX-raysUVVis.InfraredMicrowavesRadioFERMICHANDRAHUBBLEVLTJWSTALMAPLANCKFASTLOFAR
Fermi (γ)Chandra (X)Hubble (UV/Vis)VLT (optical)JWST (IR)ALMA (mm)Planck (CMB)FAST (radio)LOFAR (radio)
Gamma rays
< 10 pm

The most energetic photons. Emitted by gamma-ray bursts, black holes and the most violent events in the universe.

X-rays
10 pm – 10 nm

They reveal ultra-hot gases (millions of °C) around black holes and in galaxy clusters. Observed by Chandra, XMM-Newton.

Ultraviolet
10–400 nm

Ultraviolet light shows the hottest stars and star-forming regions. Hubble excels here.

Visible
400–700 nm

The only band our eyes see. This is the human eye, the camera, and classic optical telescopes (VLT, Keck, ELT).

Infrared
700 nm – 1 mm

Pierces cosmic dust to see newborn stars and exoplanets. JWST’s specialty.

And the human eye in all this?

Our eye sees only a tiny band of the spectrum: between 400 and 700 nanometres (from violet to red). That is why telescopes were invented for every other wavelength, each instrument opening a new “colour” of the invisible universe.